# Thumper--a 1 3/8" bore i.c. engine



## Brian Rupnow (Feb 27, 2020)

I have developed the concept and plans  for this engine over the last couple of days, under a thread titled "A different engine configuration".  Now that the plans are 95% blocked out, I am going to create this new thread dealing with the actual fabrication of the engine. You are all invited to follow along, and assuming this engine is a success, I will be selling the plans after I am finished.---Brian Rupnow


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## Ghosty (Feb 27, 2020)

Brian, I will be watching along with this build, cheers


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## Brian Rupnow (Feb 27, 2020)

Just so ya know----I'm going a bit beyond my comfort zone here. I haven't made an engine over 1" bore before. All rotating shafts will be on sealed ball bearings except the big and small end of the con rods (both of them).  I'm done with bronze bushings. The Rockerblock style is tried and proven on one of my previous builds. I will be using purchased cast iron rings (because I really suck at making them). My ignition will be the old tried and true Chrysler ignition points, and my CM6 sparkplug has a 10mm threaded end and can be purchased at an auto parts store. The cylinder will be made from grey cast iron, and virtually everything else except the shafts will be made from bar stock aluminum. The flywheels will be fabricated from mild steel, and I hope to make them using my new TIG welder that I bought this week. My ultimate goal is to build an engine powerful enough to drive my edger. A piston of 1 3/8" diameter has almost twice the surface area that a 1" diameter piston has.


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## Brian Rupnow (Feb 28, 2020)

This morning's work was to add in all the other things you need to have with an i.c. engine, namely the gas tank and a way to support it, some shafts, and a whole bunch of drilled and tapped holes with matching counterbored holes. There are more elegant ways to support a gas tank, but this is simple and gives you the capability of raising or lowering the gas tank. (which can have an effect on the way the engine runs).


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## Brian Rupnow (Feb 28, 2020)

I've spent most of the afternoon making detail drawings of the new engine. It has snowed here for the last 48 hours and it's still snowing. It's the biggest snowstorm I've seen in years. There is a rather zen like peacefulness in making detail drawings. All of the heavy lifting gets done during the in initial design process. I have to go down street Monday and buy material. My new welder  hasn't showed up here yet, so I guess I won't see it until Monday. I've spoken to the people at Canadian Bearings in Barrie and the have the two sizes of sealed ball bearings that I need---Monday. I've spoken to the fellow who makes rings for model engines and he has the piston rings I need for $5 each, and I'll probably order them on Monday.---Monday may be a busy day!!!


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## Brian Rupnow (Feb 28, 2020)

I just snapped this picture of my truck in the driveway--I'm waiting for the plow to come. They are calling for more snow tonight, tomorrow and tomorrow evening.


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## CFLBob (Feb 28, 2020)

Count me following, too, Brian.  The way I figure it, that's 2.0 cubic inches, and I think that should be able to do useful work.  

It seems that getting above 1 HP is where that becomes realistic.

*EDIT to add:*  Will the flywheels be set up to blow air across the engine?  Will they both have to move air in the same direction?


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## Brian Rupnow (Feb 29, 2020)

Yes, they will both be set up to flow air in the same direction. If they blew air towards each other or away from each other, I don't really know what the air flow would be like. If they both blow air the same direction, then I can be sure that they push/pull the air in the same direction, over the cylinder.


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## Brian Rupnow (Feb 29, 2020)

The design is complete and the detail drawings are all finished. The only parts not shown on the drawing are the valve springs. I will root around in my stockpile of odds and ends to see what I actually have to start working on, knowing that I will buy the bulk of the material on Monday to really get into this.


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## a41capt (Feb 29, 2020)

Brian,
Another beautiful design, and I will be following and looking forward to the first run!

Since you announced that you’ve purchased a TIG machine, I thought it would be used to weld the aluminum engine components (such as the frame) rather than bolt them together.  Is there a reason for not welding in your design?  As a budding model engineer, this concept is of interest to me.

Thanks so much for your contributions. To a relative newbie such as myself, they’re very inspirational and get my own creative juices flowing!

John W
Camp Verde, AZ USA


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## Brian Rupnow (Feb 29, 2020)

Yes, there is  very good reason for not welding the frame together. I build these engines and then sell the plans all over the world. Most of the people who buy my plans have a small lathe and mill, and not much else in the line of fabrication equipment. Even the flywheels, which I will fabricate with the tig welder can be made from simple discs of steel or brass.If you need a tig welder to make my engines, nobody would buy the plans.


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## a41capt (Feb 29, 2020)

Brian Rupnow said:


> Yes, there is  very good reason for not welding the frame together. I build these engines and then sell the plans all over the world. Most of the people who buy my plans have a small lathe and mill, and not much else in the line of fabrication equipment. Even the flywheels, which I will fabricate with the tig welder can be made from simple discs of steel or brass.If you need a tig welder to make my engines, nobody would buy the plans.



Ahh, excellent reason indeed!  As a fairly accomplished TIG welder, I was thinking too small!

Now, if I could be a “fairly accomplished” machinist as well...

Thanks again, and I can’t wait to see the work progress on yet another masterpiece!

John W
Camp Verde, AZ. USA


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## LorenOtto (Feb 29, 2020)

Brian Rupnow said:


> I have developed the concept and plans  for this engine over the last couple of days, under a thread titled "A different engine configuration".  Now that the plans are 95% blocked out, I am going to create this new thread dealing with the actual fabrication of the engine. You are all invited to follow along, and assuming this engine is a success, I will be selling the plans after I am finished.---Brian Rupnow


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## LorenOtto (Feb 29, 2020)

I will take much pleasure in watching you develop this unique design.


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## Brian Rupnow (Feb 29, 2020)

So what do you do when it's the middle of winter and you don't want to go and play outside?--Well of course, you make parts!!! I've rootled thru all of my scraps and came up with enough material to make the main rocker, the two cross pins for the ends of it, and the two spacers that keep the rocker centered in the frame. I have to buy a bunch of aluminum plate, but I've got enough odds and ends of material here to keep me busy over the weekend.


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## Brian Rupnow (Mar 1, 2020)

Today was connecting rod day at my house. My, but there is a lot of work in one lousy connecting rod---and it isn't finished yet. I still have to turn 0.031" off each side and leave a boss at both ends. Also, I've added a shot of the biggest icicle in the world. It's hanging off the eves over my back deck. I don't think I have ever seen an icicle this big. It's over six foot long!!!


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## Ghosty (Mar 1, 2020)

Brian,
A tad cool at your place, opposite here today, it was 25deg C(77 F) at 5:30 this morning, almost 30deg C(86 F) @ 9:30am


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## Brian Rupnow (Mar 1, 2020)

Yes Ghosty---It's easy to tell that we live at opposite ends of the world.--


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## werowance (Mar 2, 2020)

just subscribing to the thread so I can follow along.  looking good Brian.


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## Brian Rupnow (Mar 2, 2020)

Just got back from running around town. In one picture you see all of the material and bearings for Thumper ($98.00) in the other you see my new TIG welder, so new I haven't got it out of the box yet.


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## Brian Rupnow (Mar 2, 2020)

And what's better than having one connecting rod?---Well of course, it's having two connecting rods. Now I have to go and chase down bearings and plates. Somehow I managed to get my posts out of order here, but that's okay.


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## a41capt (Mar 2, 2020)

Enjoy your new welder Bryan!

John W


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## Brian Hutchings (Mar 3, 2020)

Someone mentioned subscribing so that they can keep up to date; how does one do that?
Brian (neither hot nor cold)


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## werowance (Mar 3, 2020)

Brian Hutchings said:


> Someone mentioned subscribing so that they can keep up to date; how does one do that?
> Brian (neither hot nor cold)



by just posting to the thread. that's all it takes then you get email notices / alerts on this site in the upper right corner of the page when someone replies or adds new stuff to the thread.

when you posted it subscribed you to the thread automaticly.  so that's why I posted so I would know when new info was posted.

   cold and rainy here........


edit - I think its called "watched" threads not subscribed which is what I called it.


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## Brian Hutchings (Mar 3, 2020)

Many thanks.
Brian


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## awake (Mar 3, 2020)

Brian, I look forward to hearing about your experience with the new TIG welder. I recently upgraded from a fairly simple DC-only TIG welder to an AC-DC with all sorts of settings available - and some of those, especially pulse, have been very useful already, though I still have a long ways to go in learning the best way to set it up for various tasks.

As an example of how pulse can help, I tried TIG welding a broken bandsaw blade with the new welder. In the past, I've occasionally been able to do that, but more often than not have blown out a piece of the blade. With the new welder, using pulse, it was easy-peasy.

Is your welder one that uses all-digital control for the various settings, or does it use analog knobs? Mine is the latter ... and I'm still debating whether I wish I would have spent the extra money for the former. The downside of the digital-only controls, from what I can tell, is that you have to cycle through all of the settings to see what they are; the upside is you get precise control. The downside of the analog controls is that it is a bit of guesswork to get the exact setting you want, but you can see how everything is set by glancing at the various knobs.


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## Brian Rupnow (Mar 3, 2020)

My new welder has analog controls. I haven't used it, just unpacked it, made sure nothing was broken or missing, read all the instructions, and watched "how to" videos on YouTube. I have to check out my electrical supply. I have one 220 volt outlet in my garage, that runs either my air compressor or my old Lincoln tombstone welder. Apparently this new welder can do TIG or plain stick welding.  I may sell the old Lincoln tombstone and the helmet that goes with it, just to free up some room in my garage. It is still heavy winter here and my garage isn't heated.


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## a41capt (Mar 3, 2020)

awake said:


> Brian, I look forward to hearing about your experience with the new TIG welder. I recently upgraded from a fairly simple DC-only TIG welder to an AC-DC with all sorts of settings available - and some of those, especially pulse, have been very useful already, though I still have a long ways to go in learning the best way to set it up for various tasks.
> 
> As an example of how pulse can help, I tried TIG welding a broken bandsaw blade with the new welder. In the past, I've occasionally been able to do that, but more often than not have blown out a piece of the blade. With the new welder, using pulse, it was easy-peasy.
> 
> Is your welder one that uses all-digital control for the various settings, or does it use analog knobs? Mine is the latter ... and I'm still debating whether I wish I would have spent the extra money for the former. The downside of the digital-only controls, from what I can tell, is that you have to cycle through all of the settings to see what they are; the upside is you get precise control. The downside of the analog controls is that it is a bit of guesswork to get the exact setting you want, but you can see how everything is set by glancing at the various knobs.



I own the Everlast PowerTIG 250ex and it has the best of both worlds in a main power knob with an LED display, and analog knobs for pulse, peak and frequency knobs, as well as analog for the remaining spot timer, up current down current, etc.

My TIG education was on a Lincoln IdealArc transformer welder back in 1972, and this new IGBT technology with adjustable frequency control is nothing short of miraculous! Back in the day, you had no control over arc wander and penetration, 60Hz was it.  Now I have an almost infinite control over electrode positive and negative balance, and dialing in penetration vs. cleaning on aluminum makes for great welding.

I’ll have to try using it for welding a broken bandsaw blade as suggested. Problem is, I tend to wear them out before they break!

Now, back on topic.  Brian, will you be using cast iron rings on this engine?  If so, are you making your own or buying pre-made?

Thanks for the great project!
John W
Camp Verde, AZ USA


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## billco (Mar 3, 2020)

Brian Hutchings said:


> Someone mentioned subscribing so that they can keep up to date; how does one do that?
> Brian (neither hot nor cold)



I will also be watching 
Thank you for your great posts 
So much to learn


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## awake (Mar 3, 2020)

a41capt said:


> I own the Everlast PowerTIG 250ex and it has the best of both worlds in a main power knob with an LED display, and analog knobs for pulse, peak and frequency knobs, as well as analog for the remaining spot timer, up current down current, etc.



The machine I upgraded to is also an Everlast, and has nearly identical controls to your PowerTIG 250ex, but it is a three-in-one (plasma, stick, TIG): https://www.everlastgenerators.com/product/multi-process-tig-stick-plasma/powerpro-205si. The only difference I can see in the controls is the air pressure regulator instead of the spot welder control. Mine also tops out at 200 amps rather than 250, but that is as much as I have ever needed. And I got it on an incredible Black Friday sale, so saved a couple of hundred off of the regularly-discounted price!

Brian, I tried to look up the welder you bought; I'm not entirely sure I have found the right one, but it looks like you may not have all of the bells and whistles that a41capt and I are talking about. It does look like there is a switch that enables some sort of pulse, with either one or two fixed settings; I can't find any information on what those settings might be. It will be interesting to hear how useful this is without the ability to adjust the on/off percentages, background amps, and so on. But all that said, I did quite nicely for years with my DC-only TIG welder that lacked even a fixed-setting pulse control. Just having the ability to adjust as you go with the foot pedal is a game-changer. The only reason I upgraded to my new machine was the need for AC in order to weld aluminum.

I predict you will get lots and lots of use and enjoyment out of the new welder. Before you sell the tombstone, check the duty cycle for the new welder and for the old tombstone - I keep a massive old Marquette transformer machine on hand purely for those times when I need to lay down a lot of weld (stick welding) and don't want to worry about duty cycle.

BTW, as far as electrodes, I wouldn't bother with switching between various types for DC vs. AC; that used to be needed when the only choices were thoriated and pure, but these days you can do very nicely using 2% lanthanated electrodes for everything you do.


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## a41capt (Mar 3, 2020)

Brian,

If you’ve got the room, keep your Lincoln BuzzBox as a backup so you don’t have to tear down your TIG unit for a quick AC stick weld job. I kept my Miller Thunderbolt for the same reason when I upgraded, and while a DC welder is preferable for mild steel stick welding work, the convenience of plugging in and running a bead is a lot like having multiple lathes!

John W


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## Brian Rupnow (Mar 3, 2020)

In keeping with my "Make at least one part a day" policy, here is todays part. It is the cylinder mounting plate. Nothing really fancy here, but quite a few holes in different places. Thank God for DRO's.


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## Brian Rupnow (Mar 3, 2020)

I am going to buy the cast iron rings for this engine. I really suck at making rings, I only need two, and they are only $5 each---


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## L98fiero (Mar 4, 2020)

Brian Rupnow said:


> My new welder has analog controls. I haven't used it, just unpacked it, made sure nothing was broken or missing, read all the instructions, and watched "how to" videos on YouTube. I have to check out my electrical supply. I have one 220 volt outlet in my garage, that runs either my air compressor or my old Lincoln tombstone welder. Apparently this new welder can do TIG or plain stick welding.  I may sell the old Lincoln tombstone and the helmet that goes with it, just to free up some room in my garage. It is still heavy winter here and my garage isn't heated.


Brian, I too have the Everlast 250ex, great welder and Duncan at Everlast is super to deal with. If you are replacing your helmet, Princess Auto has a great auto-darkening helmet, it's a lot more expensive than the old style green ones but the view has nearly no color until the arc is struck, I got mine on sale for about $150 and well worth the price.


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## Brian Rupnow (Mar 4, 2020)

Actually, I lucked out. As part of the promotion for this welder, I got a free auto darkening adjustable power welding helmet.


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## awake (Mar 4, 2020)

Auto-darkening helmets - what a great invention! Great that you got one with the welder.


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## Brian Rupnow (Mar 4, 2020)

This mornings work yielded up a finished baseplate and a muffler. Neither were difficult parts to make. I have to head downtown to the nut and bolt shop now, and do a bunch of searching for the correct receptacle box to plug my new tig welder into.


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## werowance (Mar 4, 2020)

on your mufflers,  I notice some similarity with ones on your other engines.  is there packing material or holes drilled on an internal pipe or is it just a straight pipe?   didn't know if its one piece or multi piece with some sort of silencing effect?


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## Brian Rupnow (Mar 4, 2020)

Nah, its solid aluminum with a hole through the center. It's cosmetic only.


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## awake (Mar 4, 2020)

Okay, for a minute there I was confused - wouldn't a solid aluminum piece block all of the exhaust gas?!? Then I read it again and saw the "hole through the center." Whew!


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## Brian Rupnow (Mar 4, 2020)

I actually did build a working muffler with baffles, etcetera for one of my engines. It did quiet the engine down quite considerably. It was just one of the ten thousand things I like to try to see "what if".


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## Brian Rupnow (Mar 4, 2020)

Tomorrow I will designate as "Side plate day". The side-plates are pretty well identical, except that the counterbored holes make them right and left hand. It is much less work if I can do all of the profile work on both plates at the same time. I will bolt the plates together , putting the connecting holes somewhere in the center area that gets milled away as a "last step". One plate will be drilled and tapped, the other will have countersunk or counterbored holes in it so it will lay flat. even the counterbored holes can be put in---When I separate the plates the bottom plate can be flipped over and counterbored.


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## a41capt (Mar 5, 2020)

Brian Rupnow said:


> Tomorrow I will designate as "Side plate day". The side-plates are pretty well identical, except that the counterbored holes make them right and left hand. It is much less work if I can do all of the profile work on both plates at the same time. I will bolt the plates together , putting the connecting holes somewhere in the center area that gets milled away as a "last step". One plate will be drilled and tapped, the other will have countersunk or counterbored holes in it so it will lay flat. even the counterbored holes can be put in---When I separate the plates the bottom plate can be flipped over and counterbored.



I’ve been doing similar stuff  lately with components that are mirror images of each other, and have a lot of success using super glue as the bonding agent.  When I’m done with the work, I either use a heat gun to separate the pieces if large, or an acetone soak for pieces that fit into one of my small tubs.

One way or another, they all get an acetone cleaning to remove the last traces of the glue.  I guess I’ve been lucky so far in that they’ve all held together and didn’t separate during machining.  Probably wouldn’t work well if there was higher heat.

John W


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## Brian Rupnow (Mar 5, 2020)

I came downstairs this morning with my cup of coffee and began laying out my side-plates. At this point I will join two pieces of material  together, so all of the drilling and cutting applications ca be done at once on both plates. I trust my DRO's completely, but still lay everything out beforehand, just to be sure my layout makes sense and to give me assurance that I have the DRO in the places I really want to be.


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## Brian Rupnow (Mar 5, 2020)

Here we are with all of the major holes drilled. Eventually, all the center has to be cut out/machined away, and the outer profile machined. You can see the heads of the two 1/4" bolts which are holding the plates together.


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## werowance (Mar 5, 2020)

maybe 1 hole for the outside radius not drilled?


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## Brian Rupnow (Mar 5, 2020)

This pretty much covers the work that can be done with the two plates still bolted together. The exterior profile is completely machined, and a good portion of the inner profile. And it comes close to my own limits for the day. Tomorrow I will separate the plates and mill away what is left of the inner profile, and add some counterbores and some tapped holes.


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## Brian Rupnow (Mar 5, 2020)

Werowance--thanks for the reminder. I actually thought of that while eating my lunch. I'm glad that I hadn't torn down the set-up.---Brian


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## werowance (Mar 6, 2020)

whats your plan of attack to cut this radius?  freehand, rotary table or ??


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## Brian Rupnow (Mar 6, 2020)

After I get the rest of the inside profile cleaned out (within the next half hour) I will stand a short 1/2" diameter dowel vertically into the mill vice with about 3/4" protruding above the vice jaws. Then set a thick washer over the post, then set the 1/2" plate over the dowel. Bring the milling cutter down to a points where it is lined up with the underside of the plate, and start the mill on it's lowest speed. Then when I am sure it isn't going to "grab", I manually turn the plate on the 1/2" dowel, forcing the uncut plate into the cutter. This cuts a perfect radius, and is definitely not recommended as a safe practice.


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## Brian Rupnow (Mar 6, 2020)

Today seen the completion of the side plates and first assembly of the overall frame. Everything goes together and everything clears. I will now order my piston rings. I don't want to make the piston until I have the rings and I don't want to make the cylinder until I have the piston. While I wait for the rings I will make the next part which sets on top, where the bearing caps would usually go.


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## Brian Rupnow (Mar 6, 2020)

The next part that sets where the bearing caps would normally go is going to make my old heart go Pitter-Patter!! It is going to be a cam box, which has the camshaft bearings, camshaft and cams in it. The bolts which thread into the rest of the frame on each side of the main bearings pass thru this in clearance holes. The "window" cut into the side allows me access to the cams to set them at the proper rotational aspect.


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## Brian Rupnow (Mar 7, 2020)

Today I machined the cam box. It is finished except for the bores for the camshaft and bearings and the recess and clearance for the crankshaft bearings. I'm not sure if I can get #10 bolts that are long enough, but if I can't, then studs and nuts will work.


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## Brian Rupnow (Mar 8, 2020)

Something fishy is going on. I use ImageShack to post my photos on this forum. It automatically resizes my pictures to a size which is compatible with posting on the forum. Suddenly about half my posted pictures are HUGE on this forum only. Is anybody else seeing that with the pictures I post?--Brian


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## CFLBob (Mar 8, 2020)

The first thing I noticed was the picture I got in the email was full-sized while the one on here was regular size.  That was a few days ago.   Within the day that turned into both the picture in the email and the copy here were both bigger. 

I always cut my pictures down in size manually before I put them up, but I thought they'd end up a bit smaller than I'd post.  I do that here with the "upload a file" button, not a place like ImageShack.


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## dsage (Mar 9, 2020)

They all look fine to me Brian. I went back right to the beginning. Some pictures have the "click here to enlarge the picture" click box at the top. (which makes them zoom about 10x - sort of useless). So maybe those were too big to fit. But they look ok in the post.
The photos I'm posting on my build are fine. But I just shoot them in 3Meg mode on my crappy camera and simply copy and paste them while I'm editing my post. I don't bother editing them before posting. They seem to fit and don't have the "click to enlarge" option. Dumb luck on the file sizing I guess.

https://www.homemodelenginemachinis...ngine-making-it-work.31960/page-2#post-335245


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## Brian Rupnow (Mar 9, 2020)

I was able to buy #10-24 shcs x 3" long today, and shortened them to 2 3/8". They worked fine and had enough thread that I didn't need to extend the thread with my #10-24 die. I've had some other stuff going on today, so didn't get any real machining time in on my project. Tomorrow I will set everything up on my milling machine and drill/bore the clearance for the crankshaft and the recessed bore for the crankshaft bearings, as well as the bores for the camshaft and bearings.


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## Brian Rupnow (Mar 10, 2020)

This morning was time to bore the cam box. I have learned thru experience, that this should be done with the cam box attached to the engine. First step was to attach the entire engine to an angle plate, set up square to the mill bed. The cam box was removed, and the bearing which sets in the sideplate recess was loctited to a piece of 1/2" shaft and held in the mill chuck. This allowed me to move the mill bed in both the x and y axis until the bearing was an exact fit into the recess cut for it. the DRO was set to "0" and the cam box was securely bolted in place. That allowed me to put in both the clearance hole for the crankshaft and the bore in the exact place it should be.  Then it was time to move the mill table the required amount to put in the clearance hole in the cam box for the camshaft and cam bearing. I will now flip the engine over and repeat for the far side holes. I had to use a boring head to prepare the recess for the crankshaft. I got lucky and had an endmill of the exact size I needed for the camshaft bearing recess.


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## Brian Rupnow (Mar 10, 2020)

And here we are with all of the ball bearings and dummy shafts in place.


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## Brian Rupnow (Mar 10, 2020)

I can't reach Dave Reed at Ringspacers.com. I have emailed him and tried to telephone him, but nada. I want to buy a set of two rings for this engine I'm building but I can't reach Dave, who I've dealt with before. Are there any other reputable dealers that sell 1 3/8" dia x 3/32" thick piston rings for a 4 cycle i.c. engine?---Brian


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## awake (Mar 10, 2020)

Brian, the engine is progressing nicely!

Sorry to hear that you are having trouble ringing Dave. I mean, getting rings from Dave. Or both. Wait, now I've confused myself ...


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## Brian Rupnow (Mar 10, 2020)

Regardless of whether I go with 1 3/8" bore or have to change over to a metric semi equivalent 35 mm (in order to get rings), the gears won't change. I have the material on hand to make the small gear from mild steel, and the large gear from cast iron. I would rather make the large gear from brass, but it's gotten too spendy $$$ for my blood.


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## dsage (Mar 10, 2020)

Try Debolt Machine. You didn't specify the thickness (or whatever way your looking at it - the ring depth).
These are 1-3/8 x 3/32 x .060
A good company to deal with. Always at the NAMES show in Detroit.

https://www.deboltmachine.com/products/1-3-8-piston-ring


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## Brian Rupnow (Mar 10, 2020)

I just sent an inquiery to Debolt about his rings. There is nowhere on his order form to say that you are Canadian, so I sent him an email.


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## dsage (Mar 10, 2020)

On the link I sent I think it says to go to the home page for info on "International" orders but there it says for overseas orders. I'm sure he'll get you straightened out with the correct shipping. Call if he doesn't answer the email.
Keep us posted.


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## Brian Rupnow (Mar 11, 2020)

I've just had one of those King Midas in Reverse days.---Everything I touched today has turned to crap!!! As a consequence, I don't have any nicely machined gears to show you.--On the plus side of things, I found a nasty old chunk of brass that was big enough to make the blank for the large gear. I have company coming to my little shop tomorrow, so I have to stop machining for the day and go into housekeeping mode. My shop and office look like a rats nest caught in a hurricane.


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## Brian Rupnow (Mar 12, 2020)

Today was a much more satisfying day than yesterday. This morning I hosted a meeting of myself and two other gentlemen who's interests lay roughly in the same direction. One fellow is an engineer who operates a steam excursion train out of Huntsville in the summertime (about 70 miles north of where I am), and the other chap is from Wasaga beach and has a background in model trains and all things electronic. A fourth guy lives in Toronto and couldn't make it up to Barrie today. After they left, I set yesterdays gear blanks up on the mill and turned them into real gears. They seem to fit just fine where they are intended to.---In other news---Barrie got it's first case of Corona virus today, a man in his fourties who just returned from a trip to Germany. This scares me.  They say it kills mostly old guys. Damn---that's me. I'm an old guy!!!


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## Brian Rupnow (Mar 12, 2020)

I decided today to make the support which is the pivot for the rocker arms a different way. I have changed it to a flat plate with two guide bushings for the lifters, and made up a different piece (colored grey in the picture) which attaches to the top of the cylinder head with three of the head bolts.


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## awake (Mar 12, 2020)

Brian, good work on the gears. Meanwhile, what led to the change on the rocker arm support - easier to make, or better action, or ???


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## Brian Rupnow (Mar 12, 2020)

The way I had it originally, it was made totally from aluminum, and would have required a ton of machining. I do not currently have anything set up to weld aluminum. The way I have it now it is just a piece of flat plate with some holes in it. The new support I show can be made from 2 parts silver soldered together, using either brass or mild steel, or a combination of the two materials.


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## awake (Mar 12, 2020)

I had wondered if you were planning to mill the original all from one piece - that would definitely be a lot of work and a lot of swarf. As for welding aluminum ... my new welder can do it (as can yours, I think?), but my first few attempts have been, shall we say, not yet ready for prime time!


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## a41capt (Mar 13, 2020)

awake said:


> I had wondered if you were planning to mill the original all from one piece - that would definitely be a lot of work and a lot of swarf. As for welding aluminum ... my new welder can do it (as can yours, I think?), but my first few attempts have been, shall we say, not yet ready for prime time!



Remember that aluminum requires 10 to 30 percent more heat to weld it.  Additionally, even one day’s worth of oxidation can wreak havoc with your welding, as the melting point of the oxide is higher than the melting point of the aluminum itself, which means you could blow out your aluminum before the oxide melts!

As a fantastic conductor of heat, that increased amperage is necessary because the heat runs away faster than a Tokyo resident fleeing Godzilla!  Keep your arc as short as you comfortably can, keep the cleaning (electrode positive) to about 35% and 65% penetration (electrode negative) and scrub the weld site with a new (dedicated) stainless steel brush as late in the prep process as possible before welding!

Before you move to pulse welding, get used to controlling your heat with the pedal, and remember that “stacking dimes’ is pretty, but not necessarily the best penetrating or strongest weld.

Good luck, and the only way you get better is burning rod and laying down beads.

John W


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## awake (Mar 13, 2020)

Thanks, John. I know the theory, but always good to be reminded. The part that is sorely lacking for me is the very last sentence - I need lots of "hood time"!


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## dsage (Mar 13, 2020)

Brian:
Now that you have your  new TIG machine give TIG brazing a try. It takes a lot less heat than silver soldering (no need to get the whole part red hot - heat is confined to the work area) and no clean up of the tough flux. It takes a bit of practice to not melt the part metal (as you do with welding). I used Silicon Bronze rod which is a bit pricey but cheaper than silver solder.


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## awake (Mar 13, 2020)

TIG brazing is something else that I still need more practice on. Mind you, I have done it successfully, particularly on a couple of cast iron repairs, but in both cases I got a bit hot and melted some of the CI into the braze. The result was hard as a rock, but I was lucky enough not to have any cracks.

One thing to be aware of - maybe obvious to others, but at first I thought it would be like regular brazing or like soldering, where the braze / solder will wick into the joint. That is not the case with TIG brazing - it lays on the surface and makes a strong joint, but does not wick into the joint.


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## Brian Rupnow (Mar 13, 2020)

Today yielded a new top plate which bolts to the top of my cam box, and a 1 3/8" diameter piston. The piston has had everything done on it that can be done on my lathe. Tomorrow it will spend a bit of time with my mill and rotary table to get finished up.


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## Brian Rupnow (Mar 14, 2020)

Today was cylinder day. The cylinder is made from cast iron. The piston does fit the bore---with a little persuasion. That is exactly what I wanted. Tomorrow I will run my brake cylinder hone thru the bore of the cylinder, and if I need to, will coat the piston with a bit of aluminum oxide #600 paste and lap the piston into the cylinder. I have ordered two compression rings from Debolt in USA.


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## CFLBob (Mar 14, 2020)

Brian, did you ever get the piston rings you needed?


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## Brian Rupnow (Mar 15, 2020)

Yes, as I said in the previous post, I ordered a set of two rings from Debolt in USA.


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## dsage (Mar 15, 2020)

Brian: Unless you have received the rings already you have the cart before the horse.
The cylinder needs to be EXACTLY the diameter of the OD of the rings. So you should be waiting until you know what that diameter needs to be (measured). Otherwise the rings will not be round when they are inserted in the cylinder (little to no compression).
Also the piston work should be down the road a bit since you are buying rings. I see you have cut the ring grooves already. Those should be cut with a depth according to the rings ID for  a few thou clearance at the back. And a width within about 1 thou of ring width (thickness?)
Then the piston should be a few thou less than the diameter of the cylinder since the aluminum will expand faster than the cast iron. (possible seize up). Not lapped to fit.
I'm just mentioning it because this may be the reason you have had problems with compression in the past.


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## a41capt (Mar 15, 2020)

Brian Rupnow said:


> Yes, as I said in the previous post, I ordered a set of two rings from Debolt in USA.



Brian, et. al.,

I am about 3/4 of the way through my building of the Henry Ford kitchen sink engine (my first IC engine from Mr. Ridenour’s plans) and already considering a design of my own.

My question to Brian, who has a significant amount of design experience is, does there exist a formula for determining top and bottom clearance in piston ring grooves for cast iron rings?

Just thinking ahead, and knowing of your successes, I thought if anyone knew, it’d be you! 

Thanks in advance,
John W


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## Brian Rupnow (Mar 15, 2020)

The ring grooves cut into the piston were recommended by the person I bought the rings from. I have not had compression issues caused by rings in the past. Valves, yes, rings, no. I will let you know how my piston/cylinder sizing works out. This is only the second set of rings I have ever purchased. The first set went onto a lapped aluminum piston in a cast iron cylinder on my vertical hit and miss engine. Granted, hit and miss engines don't get very hot.  I hear you. Your concern has ben registered.---Brian


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## Brian Rupnow (Mar 15, 2020)

a41capt---I don't personally know of a formula. I use the ring groove recommended by the manufacturer of the rings. Many of my engines have used a 1/16" cross section Viton o-ring.  The piston groove for those would be 0.094" wide x 0.057" deep, and use only one ring per piston.


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## a41capt (Mar 15, 2020)

Brian Rupnow said:


> a41capt---I don't personally know of a formula. I use the ring groove recommended by the manufacturer of the rings. Many of my engines have used a 1/16" cross section Viton o-ring.  The piston groove for those would be 0.094" wide x 0.057" deep, and use only one ring per piston.



Thanks Brian, that’s what I’m currently using from Leon Ridenour’s instructions. With a two ring setup, I’m hoping my minor deviation in ring groove width on the bottom ring (.002” oversized) won’t impact the compression enough to impact my getting it to run.

John W


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## Brian Rupnow (Mar 16, 2020)

Today we have a cylinder head.--And trust me, lads, there are some strange and wonderful set-ups involved with making this part. Everything came out like the drawing asked for, but there was a bit of tongue biting and butt clenching involved!!!


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## Brian Rupnow (Mar 16, 2020)

-Today I drilled and tapped both ends of the cylinder for #8-32 bolts, and happily everything bolts together properly.  I honed the cylinder with my 3 stone brake hone, a total of 50 slow strokes end to end. I hone it dry with no lubricant. The piston was quite happy to start into the cylinder for about half it's length, then started to tighten up. I coated the piston with #600 grit aluminum oxide paste, and mounted the cylinder in the three jaw chuck on my lathe. I have a temporary handle which fits into the piston and is locked there by the wrist pin. With the lathe on it's lowest speed I began slowly working the piston into the cylinder about 1/8" at a time, ready to let go immediately if it "grabbed". When it started getting "grabby" I squirted a little #30 oil onto the piston and kept working it back and forth until it started to come out the other end of the cylinder. At that point I stopped, cleaned piston and cylinder with laquer thinners, then gave both a scrub with an old toothbrush and some dish detergent. When dry, the piston will fall thru the cylinder. If I put my hand over the end to seal it, the piston stops. This did NOT give a tight enough seal for the engine to run without rings. To run without rings, as my marine engine does, takes a much tighter fit and a much longer time lapping. I'm happy with the days work. I've had to give up taking my "Fat man's walk" in the local mall because of the virus. Yesterday I returned to my solitary walk in the woods for exercise. It is beautiful there, but we still have about a foot of snow in the bush, ---I'll be glad to see spring come.---Brian


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## WOB (Mar 17, 2020)

Brian Rupnow said:


> Today was cylinder day. The cylinder is made from cast iron. The piston does fit the bore---with a little persuasion. That is exactly what I wanted. Tomorrow I will run my brake cylinder hone thru the bore of the cylinder, and if I need to, will coat the piston with a bit of aluminum oxide #600 paste and lap the piston into the cylinder. I have ordered two compression rings from Debolt in USA.


Fatal error.  Do not lap the cylinder with the piston.   The piston surface is now contaminated with lapping compound and it cannot be removed without removing metal.  The piston dia. should be about 2 thou. less than the cylinder dia. except for the piston head above the top ring which should be about 3 thou. less. to allow for thermal expansion.   So, you might be able to salvage the piston by reducing the dia. on the lathe.   However, not having the rings on hand makes it impossible to cut the ring grooves correctly unless you just lucked out.  Dsage has it right.  

WOB


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## werowance (Mar 17, 2020)

looking good Brian.

WOB,  Brian usually laps most of his pistons in (as far as I know from watching his other builds).  but I don't think he uses diamond lap to do it.  I think he has some clover which ill let him answer for sure but is just aluminum oxide (like sand paper sand) suspended in grease which I don't believe embeds (and I might be wrong) like the diamond lapping compound. 

but I will let the experts correct me on all this.  shoot I'm still learning to cut my first real cams (cheated on the Webster cam I built) so what do I know


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## Brian Rupnow (Mar 17, 2020)

Not one of my better days today. I had planned on making the rocker arm support. It is going to be made from two pieces of steel silver soldered together. I made the base first, then bolted it into position on top of the cylinder head to check the fit. Then things went astray---I picked out a piece of steel flat-bar, proceeded to shape it, drill it, mill it---and then I discovered that I was working with a piece of 1" wide bar, not 1 1/4". Misread my own drawing. Bah!!  Humbug!!  Will try that piece again tomorrow.


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## werowance (Mar 18, 2020)

time to break out the metal stretcher


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## awake (Mar 18, 2020)

werowance said:


> time to break out the metal stretcher



My motto is, "if at first it is too short, cut, cut, cut again!"


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## Brian Rupnow (Mar 18, 2020)

Perseverance pays off.--A new day, a new part. It isn't welded yet. This is one of those situations where alignment is going to be very critical. I'm going to have to build a welding fixture to perfectly align the parts. The welding fixture may be more complicated than the part.


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## Brian Rupnow (Mar 18, 2020)

Kind of a cheap and nasty welding fixture, but it will work to hold the parts in alignment while I silver solder them. I had designed something a lot fancier, but decided to go with something quick and nasty. Why didn't I bolt the pieces together?---Because I never thought of it. Where am I at with my TIG welder--I took it out of the box, had a look at it, seen that al the parts were there, read the manual, and sussed out a way to plug it into my existing 220 volt outlet. It is still winter here, and my main garage is not heated, so I've been deferring anything to do with the TiG until the weather breaks a little.


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## a41capt (Mar 18, 2020)

Brian Rupnow said:


> Kind of a cheap and nasty welding fixture, but it will work to hold the parts in alignment while I silver solder them. I had designed something a lot fancier, but decided to go with something quick and nasty. Why didn't I bolt the pieces together?---Because I never thought of it. Where am I at with my TIG welder--I took it out of the box, had a look at it, seen that al the parts were there, read the manual, and sussed out a way to plug it into my existing 220 volt outlet. It is still winter here, and my main garage is not heated, so I've been deferring anything to do with the TiG until the weather breaks a little.



Simple is smart!

John W


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## Brian Rupnow (Mar 18, 2020)

That turned out very well. The alignment seems to be about perfect. You can see in the bottom of the picture that I am working on the gas tank. I have to solder in a filler neck and j.b. weld the ends into it.


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## a41capt (Mar 18, 2020)

Brian Rupnow said:


> That turned out very well. The alignment seems to be about perfect. You can see in the bottom of the picture that I am working on the gas tank. I have to solder in a filler neck and j.b. weld the ends into it.



Brian, a quick question if you have time.  What carburetor design do you most commonly use?  I’ve been looking at Chuck Fellowes’ design for an upcoming project, and wondered if you have an opinion?

thanks in advance,
John W


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## Brian Rupnow (Mar 18, 2020)

And, with the gas tank filler neck soldered into place, that is enough for today.


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## Brian Rupnow (Mar 18, 2020)

a41capt--The carb that Chuck Fellows designed works fine. It's a bit awkward if you want to change throttle settings because you have to turn the bolt in or out to do so. I took Chucks design and changed the throttle area a bit so you can go from idle to wide open in a 1/4 turn. I am attaching the change I made to chucks carb, and also a download for a carburetor that was designed by George Britnell---Brian
http://www.mediafire.com/file/cjgmg9kj2vcgy70/RUPNOW-BRITNELL_CARB.zip/file
http://www.mediafire.com/file/lflytaolejtjd5f/CHUCK_FELLOWS_CARB.zip/file


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## a41capt (Mar 18, 2020)

Brian Rupnow said:


> a41capt--The carb that Chuck Fellows designed works fine. It's a bit awkward if you want to change throttle settings because you have to turn the bolt in or out to do so. I took Chucks design and changed the throttle area a bit so you can go from idle to wide open in a 1/4 turn. I am attaching the change I made to chucks carb, and also a download for a carburetor that was designed by George Britnell---Brian
> http://www.mediafire.com/file/cjgmg9kj2vcgy70/RUPNOW-BRITNELL_CARB.zip/file
> http://www.mediafire.com/file/lflytaolejtjd5f/CHUCK_FELLOWS_CARB.zip/file



Thanks Brian, looking forward to your newest completed project running video!


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## Brian Rupnow (Mar 19, 2020)

I've reached the point where I'm running out of big parts to make. Today I will finish the gas tank. This leaves me with a handful of small parts---valves, valve cages, cams, lifters, lifter bushings, exhaust and intake elbows and ignition cam. Of course the one big part waiting in the background is the crankshaft. I haven't decided yet whether to make it a one piece  or a "built up" style. I think I will make the rest of the pieces in order of "easiest first, most complicated last".  I think the time has also arrived to make a new "George Britnell valve seat cutter". the one I made a few years ago has been just marvelous, but it is getting old and dull, and the valves on this engine are larger than any I've made before. Goodwife and I are self isolating, but this is going to wear pretty damned thin  after a couple of weeks.


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## awake (Mar 19, 2020)

Brian, I'd like a review on how you are making the gas tank. Looks to be a steel body, yes? Soldered on filler and outlet, I presume? But here's my main question: you mention putting the ends in using JB Weld. What are you using for the sight glass (glass, acrylic, or ??), and what type of JB Weld are you using? Sight glass at both ends, or a solid cap at one end?

I have to confess that, on my nearly-finalized Webster, the gas tank and its mount turned out to be the most time consuming and frustrating parts to make. That undoubtedly had something to do with my overly complicated design, plus my poor execution ...


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## Brian Rupnow (Mar 19, 2020)

Awake--Drilled and reamed 3/8"hole in center of tank. (tank is steel seamless tubing 1 .765" o.d. x 1.213" i.d.) Took a piece of 1/2" diameter cold rolled and turned one end down to 3/8" dia. x 5/16" long. Why?---Because it will hold the mount square and true to the tank body. Counterbored both ends of tank body to 1 1/2" diameter x 1/8" deep. Silver soldered the mounting rod in place. Held the mounting rod in 3 jaw lathe chuck and drilled a 3/4" hole in opposite side of tank from mounting rod, then bored the hole out to .825" diameter x approximately 3/16" deep from outside of pipe body. Took a 1/2" standard pipe nipple and turned one end of it to 3/4" diameter. Fitted it into 3/4" hole in tank and silver soldered it in place. Turned a couple of pieces of 1/4" aluminum plate to 1 1/2" diameter. Drilled and tapped one of these with a 1/8" npt thread. You can buy a fitting at the hardware store to screw into this hole. Loaded both recesses which were counterbored into the pipe ends with original J.B. Weld, set the round aluminum plates into the recesses and put the tank into my 4" mill vice to set up for 24 hours. You can buy a "J.B.Quickweld that sets up quicker, but I find that it doesn't hold as well as the original J.B. Weld. The pretty brass cap is turned from a 1/2" standard pipe cap. Now you can tell me, this is ridiculous---Why make a gas tank so strong that a Sherman Tank could run over it without damaging it.---Because it works!!  Fooling around with thin wall tubing makes me crazy. Once the tank is all assembled, nobody knows that the tank has a wall .27" thick.


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## awake (Mar 19, 2020)

Brian Rupnow said:


> Awake--Drilled and reamed 3/8"hole in center of tank. (tank is steel seamless tubing 1 .765" o.d. x 1.213" i.d.) Took a piece of 1/2" diameter cold rolled and turned one end down to 3/8" dia. x 5/16" long. Why?---Because it will hold the mount square and true to the tank body. Counterbored both ends of tank body to 1 1/2" diameter x 1/8" deep. Silver soldered the mounting rod in place. Held the mounting rod in 3 jaw lathe chuck and drilled a 3/4" hole in opposite side of tank from mounting rod, then bored the hole out to .825" diameter x approximately 3/16" deep from outside of pipe body. Took a 1/2" standard pipe nipple and turned one end of it to 3/4" diameter. Fitted it into 3/4" hole in tank and silver soldered it in place. Turned a couple of pieces of 1/4" aluminum plate to 1 1/2" diameter. Drilled and tapped one of these with a 1/8" npt thread. You can buy a fitting at the hardware store to screw into this hole. Loaded both recesses which were counterbored into the pipe ends with original J.B. Weld, set the round aluminum plates into the recesses and put the tank into my 4" mill vice to set up for 24 hours. You can buy a "J.B.Quickweld that sets up quicker, but I find that it doesn't hold as well as the original J.B. Weld. The pretty brass cap is turned from a 1/2" standard pipe cap. Now you can tell me, this is ridiculous---Why make a gas tank so strong that a Sherman Tank could run over it without damaging it.---Because it works!!  Fooling around with thin wall tubing makes me crazy. Once the tank is all assembled, nobody knows that the tank has a wall .27" thick.



Very helpful, thanks! So there is no sight glass, right? That is a major reason that my tank design was so involved - trying to include a sight glass, which required a flange with an o-ring and a screw-end end piece to trap it together. I still wound up with a tiny leak, so I tried to plug it with a JB Weld branded product - but it was not the epoxy; rather a high-temp gasket product. Which turned out NOT to be resistant to gasoline.


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## Brian Rupnow (Mar 19, 2020)

A sight glass is a great thing. I have one in the gas tank for my Atkinson engine. They add another level of complexity to something that you really don't want leaking.


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## awake (Mar 19, 2020)

Wait - it's not supposed to leak? Darn - back to the drawing board ...



I had thought I was going to have to remake the tank a different way, and that would probably have been a good thing, giving me a chance to improve on some of the sloppy execution on the first go-round. But after I stripped out the JB Weld-branded non-fuel-resistant sealant, I used some actual fuel-resistant sealant instead (who knew that they made such a thing?!), and it seems to be working. So for the moment I'll live with the ugly execution - I'll try to improve on the next engine I make.


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## Brian Rupnow (Mar 19, 2020)

This afternoon seen two tappet guide bushings machined and pressed into place. I don't know exactly what grade that stick of bronze is, but it is miserable stuff to machine. All my turning was done with inserted carbide tooling. It seemed to be even harder to work with than 1018 cold rolled stock.  The gas tank still requires a little work, but I will give the j.b. weld 24 hours to set up before I do any further machining on the tank.


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## Brian Rupnow (Mar 20, 2020)

This morning we have valves. I haven't parted off the large diameter yet, as I will use it for a handle when lapping the valves into the valve cages. Now I have an admission to make--Last week when I was machining the pivot pins for the main rocker, I ended up with about 3" of brass rod left. I said to myself "Ah-ha--I'll keep this bit of brass to make valve cages from. I have looked hi and lo all day yesterday for that piece of brass, and it has disappeared. I think the fairies have been to my shop. I do have a piece of 3/4" brass that I can use, but it just kills me turning so much uber expensive brass into chips!!!


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## awake (Mar 20, 2020)

Oh, I hate it when that happens ... and it happens all too often! I'm still looking for one piece of material from months ago, except that now I've forgotten what it was. But I'm sure I'll recognize it when I finally do stumble across it!


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## Brian Rupnow (Mar 20, 2020)

The gas tank is finished and the valve cages have been made. I have to make a new valve seat cutting tool because I want to put the chamfer into the valve cages before I press and Loctite them into the cylinder head. The hole thru the side of the cages will be drilled thru the cylinder head and the cages after they have been assembled together.


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## Ghosty (Mar 20, 2020)

(I ended up with about 3" of brass rod left. I said to myself "Ah-ha--I'll keep this bit of brass to make valve cages from.)
It's OK Brian, you will find it tomorrow


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## dsage (Mar 20, 2020)

Hey Brian:
You might want to look this guy up. He's a Youtuber in / around Barrie as well and is looking for some help operating his new machines from Craftex from Busy Bee. He runs a small engine repair shop. He might be a good source of info and  perhaps small parts for your engine builds.


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## Brian Rupnow (Mar 20, 2020)

dsage--Normally I would jump on this and try to find the guy to help him. However, with this current virus scare, wife and I are locked down and self isolating. Wife has high blood pressure and I am an old guy, so we are trying really hard not to get exposed to any potential virus threats.---Brian


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## dsage (Mar 20, 2020)

Yes. I thought of that after posting. But maybe for future reference then. If you get his contact info you could call him if you need something. He seems  a pretty friendly and knowledgeable guy.


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## Brian Rupnow (Mar 20, 2020)

I'm getting right down to the short strokes on this engine. Have to machine a crankshaft and a couple of cams (which are the same). It's been so long since I machined a cam that I will have to study notes I made on cutting a cam using the Chuck Fellows method. Right now I'm undecided about the crankshaft, whether to machine from solid or make a "built up" crank. Looking at the engine, I see that I also need rocker arms and tappets, and the two 90 degree elbows that screw into the cylinder head. I would like to make the elbows from brass, but I don't have any brass stock to make them from. The flywheels are going to be something "special", and right at the moment I don't have any stock to make them from. It's plain that after my two weeks of  "social distancing" I'm going to have to risk it and go see my metal supplier.


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## dsage (Mar 21, 2020)

Brian:
Your stick of bronze appears (to me) to be 660 "bearing bronze". I say that because it looks to have that spiral greyish mark the length of it on the outside. Not sure why it has that and my only reason for saying that is that I've been getting it for years like that from Metal Supermarket. BUT recently I went to get some more and they seem to have stopped stocking Bronze all together at my go-to outlet. They had a small piece about 10" long left on their cutoff shelf but it was labelled Aluminum Bronze. From my experience I think it was mis-labelled. They often mislabel short ends of stuff at that store.
In any case 660 is ideal for bushings and is quite "crunchy" and small chips jump off it when machined with a sharp tool.


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## Brian Rupnow (Mar 21, 2020)

A few years ago when I built the Rockerblock engine, I did some serious studying on how to cut a cam in my milling machine. This is not the incremental version  as used by Malcolm Stride, but a totally different method based on a how to video posted by chuck Fellows. It does incorporate all of the math from the cam drawing, but uses a combination of rotary table and full depth plunge cuts with the milling machine. It is very fast and simple if you can get your head around how the set-up works. This morning I opened an old thread I had created about using this method of cutting a cam, and read a bunch of notes I made about it at the time. I set up everything according to the notes I had made and began to cut. About half way thru, my set-up slipped and I lost my reference point. I decided to continue to the end and see what conclusions I could draw from the way I had my set up. The cam was truly screwed up, but there is enough to show that if my set-up hadn't slipped, it would have given a properly shaped cam with radiused cam flanks.


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## gartof (Mar 21, 2020)

There are opportunities to learn every where.


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## Brian Rupnow (Mar 21, 2020)

And--Voila!! When your set-up doesn't slip, you get a perfect cam with the proper flank radius. Now I get to do it one more time because I need two good ones.


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## CFLBob (Mar 21, 2020)

gartof said:


> There are opportunities to learn every where.



You know that saying, "you learn something new every day?"  I always add, "if you're lucky." 

Relevant part: Brian, back to piston rings a sec.  You said you tried Dave Reed and never got an answer by email.  I was concerned he was gone as a source, but I emailed him about getting replacements for my Webster rings that I broke and he answered right away.  They're on order.


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## Brian Rupnow (Mar 21, 2020)

I tried to phone him, and I emailed him, and got no response at all. I ended up buying rings from Debolt.


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## Bill Lawson (Mar 22, 2020)

That bar does look like 950 bearing stock.  I also got piston rings from Otto Gas Engine Works.


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## L98fiero (Mar 22, 2020)

dsage said:


> Brian:
> Your stick of bronze appears (to me) to be 660 "bearing bronze". I say that because it looks to have that spiral greyish mark the length of it on the outside.


Aluminum bronze often has a similar finish but is 'whiter'/not as brassy yellow as 660 and being tough to machine is also a good indication it's not 660, if your tool is not sharp, it will just rub if your machine isn't rigid.


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## Brian Rupnow (Mar 22, 2020)

Today I made two cams and two tappets and a larger valve seating tool from 01 steel, and flame hardened them, then quenched them in some dirty old motor oil I keep  just for that purpose.  It certainly doesn't look like much, but I spent most of the day doing it. The two cams are positioned on the cam-shaft, in the cam box, and the two lifters are "posed" in the top of the bronze lifter bushings. You are not going to see the larger valve seating tool because it is really, really ugly.--but it does the job I needed it for.


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## Brian Rupnow (Mar 23, 2020)

I spent this morning working on things that mostly don't show. I lapped the valves into their seats in the valve cages, and cut off the "handles" so that the valves are now finished. I opened up a bit more clearance on the inside floor of the cam box to let both cams fully rotate without hitting something. It doesn't show in the picture, but I realized that I needed to make a shaft collar for the far end of the camshaft to keep it from floating longitudinally. I drilled and tapped both gears for set screws. I had painted the gas tank and the rocker pivot support with "semi-gloss" black paint for a little contrast, and reassembled them. I have enough brass to make a pair of nice rocker arms. I was going to drive across town and buy some 1/2" brass bar to make the large elbows that screw into the sides of the cylinder head, but I may rethink that. I may just make them out of steel.


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## Brian Rupnow (Mar 24, 2020)

Todays offering is a set of valve springs and keepers in place, as well as two brass rocker arms. The sharpie pen is just wedged in there to hold the rocker arms up. They are slightly "tail heavy" and I haven't yet made the connecting link that fits between the tappets and the end of the rocker arms.  Don't be afraid to say Hi people.  I know you are looking, because my post count keeps going up. I like to hear from you. This "social distancing" thing is starting to make me feel like Rapunzel locked in her stone tower, and I don't have any hair to let down.---Brian


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## awake (Mar 24, 2020)

Hi! I'm watching with interest. I hear you on the social isolation distancing ....


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## cheepo45 (Mar 24, 2020)

Thanks, Brian for keeping us entertained!
I look forward to every new posting.
Can't wait to see it run!  (take your time, though - I'm stuck in the house until May 15th)
 Scott


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## a41capt (Mar 25, 2020)

“This "social distancing" thing is starting to make me feel like Rapunzel locked in her stone tower, and I don't have any hair to let down.---Brian”

You keep buildin’ em Brian, we’ll keep watchin’!

John W


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## werowance (Mar 25, 2020)

Watching along Brian.   on the paint on the tank - is it fuel resistant?


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## Bighoss (Mar 25, 2020)

Enjoy reading your posts. And watching your videos keep going it will get better.
Thanks for posting


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## Brian Rupnow (Mar 25, 2020)

Fuel resistant---I don't know. The Naptha gas I use for fuel doesn't seem to affect the paint at all. I'm pretty sure that ordinary pump gasoline would wash the paint right off.


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## Peter Twissell (Mar 25, 2020)

Watching with interest here.
Wish I had time to build as quickly as you are, I've been working on my radial for 7 years now.
Retirement in 3 years!


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## Brian Rupnow (Mar 25, 2020)

Hello Peter---I am more or less retired. I don't really have much else to do, so my engines get built relatively quickly. If you can convince yourself to make at least one part per day, they come together quite fast.


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## Brian Rupnow (Mar 31, 2020)

Something really weird has happened. I have an icon on my desk top that always took me to this site. It doesn't work any more. I thought maybe the site was down because of the virus. It seems that the site is still there, but my icon doesn't work anymore. Can somebody help me please.---Brian


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## awake (Mar 31, 2020)

Brian, I don't quite know why it has stopped working, but probably the quickest fix is to delete it and create a new icon. To do that, first right click on the icon and choose Delete, then right click on the desktop and choose Create Shortcut. Copy the url to the site into the shortcut.

That was the quick version, and may have told you what you already know ... or may have been too brief. I will be happy to follow up as needed, or others may chip in with a better solution.


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## [email protected] (Mar 31, 2020)

I had the HMEM app on my android phone.  It stopped working also. I deleted it thinking I would reinstall it and solve the problem. I can't find the app in the app store now. Wondering what has happened??


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## Ghosty (Mar 31, 2020)

[email protected] said:


> I had the HMEM app on my android phone.  It stopped working also. I deleted it thinking I would reinstall it and solve the problem. I can't find the app in the app store now. Wondering what has happened??


See HMEM will be having a software update later today Post #8 this will anwser you problem


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## CFLBob (Mar 31, 2020)

I was wondering what happened to you Brian and told myself to come back here and read to see if you were taking off.  

After their software update, I had to login every day.  Reading that thread Ghosty links to, it said to delete cookies for HMEM.  That seems to have worked.  I think Awake's suggestion should get your desktop icon working again.


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## Brian Rupnow (Mar 31, 2020)

Okay--I just did what Awake suggested, and it seems to have worked. Thank you very much. Now I have to copy and post a bunch of progress.---Brian


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## Brian Rupnow (Mar 31, 2020)

Today I made funky little brass elbows. They are two part construction, silver soldered together. I did give them a soak in my citric acid solution, and scrubbed them with a small brass bristled brush, but I see in the picture that they still have a pinkish glow in spots. I will mix up a fresh batch of solution tomorrow and give them a bit more soak time. Tomorrow I will drill and tap the cylinder head and drill the exhaust and intake ports thru the cylinder head and thru the valve cages which are now loctited and lightly pressed into place. Every day I'm getting closer and closer to crankshaft time.


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## Brian Rupnow (Mar 31, 2020)

Today as I was making the brass elbows, I found myself wondering "what keeps the weight of the muffler or carburetor from making the elbows turn down, or "droop" when the engine heats up." There is no way that I can machine threads so that the elbows tighten up and "lock" in exactly the right position.----So--I went back to my 3D model for a closer look this evening. Hot Damn!!! I'm smarter than I thought. I had taken 1/4" thin hex nuts and retapped them for 3/8"-16 to use as lock nuts on the elbows to keep them positioned properly.


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## Brian Rupnow (Mar 31, 2020)

Today sees the engine completely assembled, except for crankshaft and flywheels. I have to make up some proper pivot pins with circlips for the rocker arms, but after I do that the crankshaft will be next. I am well pleased with things so far.---Brian


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## awake (Mar 31, 2020)

Great! I look forward to the posts!


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## Brian Rupnow (Mar 31, 2020)

Yesterday my rings came in from Debolt. They look good. They are exactly 0.094" thick. The grooves I cut in my piston with my 0.094" parting off tool are only 0.088" wide.  Not sure how that happened, but it should be an easy fix. The rings have a staggered lap joint in them, which I didn't know would be there, but I'm sure they will probably work okay. Some horrible economics are involved with these rings. Debolt charges $8 each USA money for these rings. Change that to Canadian dollars, pay tax on it, then pay for shipping. Ends up costing me $56 Canadian. This morning I machined and installed an ignition cam. I went to make proper pivot shafts for the rocker arms, but I'm having an issue with concentricity. I checked my lathe head-shaft and chuck, and it has 0.003 TIR, same as it had when I bought it. The main chuck will only close down to 0.150", so I'm holding an extra smaller chuck in the main chuck. I'm getting crazy concentricity results and I'm not sure why, but will probably figure it out after posting this. As of today, I've been machining on this engine for 30 days straight. I may soon take a break and start setting up my TIG welder.


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## Brian Rupnow (Mar 31, 2020)

Every time I make a built up crankshaft, it goes a little differently. The only definite thing I have taken away from previous built up cranks, is to always make the main shaft out of one long piece and then mill out the area between the crank throws as an absolute last step. The other absolute "must" is to somehow attach the two throws together, either with indestructible glue or a dab of mig weld before drilling and reaming the holes. I have never, ever had any luck gluing parts together prior to machining. The glue always fails at some critical point right in the middle of machining. I have far more faith in mig weld. I do have the material on hand to make this, and I really don't want to be running around town to buy a piece of bar large enough to turn this from solid.


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## Brian Rupnow (Mar 31, 2020)

Okay Guys, hang on tight--Here we go. The main crankshaft body is being made from 1/2" cold rolled steel, which comes in at nominally about 0.001" undersize. It is cut to finished length in the picture. The 3/8" cold rolled steel also comes in at about 0.001" undersize and is not yet cut to finished length. The two pieces of 3/4" x 1/2" cold rolled flatbar have been mig welded together at each end, and then both bored and reamed to 0.0015" undersize, on the correct centers. The pieces of bar are a bit too long at each end right now---that is to allow cutting away the welded ends and finishing them to the correct length. These pieces of flatbar were not held in the milling vice for drilling and reaming, as I never really trust my vice to hold things perfectly square and not canted a bit. They were held to the mill bed with toe clamps and a piece of 1/2" sacrificial aluminum under them for the drilling and reaming operation. After I eat some lunch I will show you what comes next.


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## Brian Rupnow (Mar 31, 2020)

The two pieces of flatbar have been trimmed to length, by trimming and finishing one end while the other end was still welded together. then the second welded end was removed, being very careful to keep both pieces identical. They were then match marked so I could keep the inward facing sides together. Then they were taken out to my large belt sander to have the corners rounded as required. That corner rounding is a clearance requirement so the crankshaft doesn't hit the underside of the cam box when it rotates. Now I'm off for my "Fat mans walk", will post more when I come back.---Brian


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## Brian Rupnow (Mar 31, 2020)

This is the magic part. This is what gives me the exact gap I require between the crankshaft cheek plates.


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## Brian Rupnow (Mar 31, 2020)

Things never go quite as I had planned, but they go, nontheless. When I went to assemble all of my parts, the 1/2" dia. shaft was nowhere near as hard a press into the cheek plates as I had hoped for. What to do, what to do. I couldn't make the hole in the plates any smaller, but I could make the diameter of the shaft a little larger. I set the shaft up in my lathe and knurled the area where the cheek plates set. This "grew" the shaft, from 0.499 up to 0.509" diameter.  I don't have any kind of press except for a 3 ton manual arbor press and my bench-top vice. I coated the knurled area with 638 Loctite, and applied  lots of brute force via my heavy hammer and things assembled just fine. Mushroomed the shaft end a little, but that cleaned up in the lathe. Right now I am not seeing any run-out in the assembled shaft, but the true story will come out tomorrow when I cut the 1/2" shaft away between the cheek plates. If it works, I'm golden.  If it doesn't work, I'm out two or three hours of work. I'm going to drill the cheek plates and shafts now for the 0.094" pins, insert them, and let everything set up over night. I'll let you know the results in the morning.


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## Brian Rupnow (Mar 31, 2020)

Well sir!!!--I am very pleased with this. Crankshaft all cleaned up, and with one end in the lathe chuck, the other end registers a 0.003" total indicated run-out. That is equal to any of the one piece crankshafts that I have machined from solid. Crankshaft fits where it is supposed to go, and goes round and round. Oh Happy day!!!


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## Brian Rupnow (Mar 31, 2020)

This morning I test fitted the rings into the cylinder. The rings have a stepped gap, however when I had a ring pressed into the cylinder and held it up to a bright light, there was still clearance for the ring gap to close a little bit more if it expands with heat. I was satisfied with the fit of both rings. I set my piston up in the lathe 3 jaw chuck and very carefully opened up the 0.086" wide gap to about 0.095" to accept the 0.094 thick rings. Any time I cut a groove in aluminum, it raises a shoulder on each side of the groove. Not much of a shoulder, but enough to keep an already tight fitting piston from sliding into the cylinder. Knowing that, and knowing that a few people were alarmed at the thought of a tight fitting aluminum piston in a cast iron cylinder, I walked a piece of 220 grit garnet paper back and forth on the piston to knock down the shoulders and take about 0.0005" off the overall piston diameter. the rings went onto the pistons with no problem. I had the cylinder off the engine, so  set it up in my 3 jaw and machined a 15 degree "lead" taper into the bottom to aid in installing the rings. everything went together fine. In about 15 minutes I'm going to make a head gasket and install it, and  then the  engine will be finished except for the flywheels.


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## Brian Rupnow (Mar 31, 2020)

The engine is finished---except for flywheels. There may  a significant time span before I get the flywheels finished. I am now turning my attention to the flywheels, which will very probably be fabricated with my new TIG welder. Thank you, to those who have followed this thread, which was started 32 days ago.


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## Brian Rupnow (Apr 1, 2020)

And this is how I spent the last two days. My welding cart which previously held only the mig has been widened about 9" and now holds both the mig and the tig. I hardly ever get to actually fabricate things any more, so I enjoyed doing it.


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## ShopShoe (Apr 2, 2020)

Brian,

Good job on your cart. I also don't get to do much fabrication anymore, so enjoy it when I can.

Thank You for posting, as always.

--ShopShoe


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## Peter Twissell (Apr 2, 2020)

TIG and MIG?
I bought a TIG welder a couple of years ago. After a little practise with TIG, I sold my MIG welder.
The only thing I could think of where the MIG would be better was car bodies and I have no intention of doing any more of that.


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## Brian Rupnow (Apr 2, 2020)

I woke up this morning thinking about how to fixture the hubs of the flywheels to cut the 45 degree slots in them. Sometimes if I model what I am thinking about, it helps to clarify things. It looks to me that if I make the yellow fixture, I can hold it in my vice and just crank the mill table back and forth in the X axis to cut the slots. I will have to drill a set of holes in the face of the hubs to register them on the yellow fixture so that they don't move while being cut.


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## awake (Apr 2, 2020)

I have never used MIG, other than briefly in a class some years ago. But I do continue to use SMAW (stick) welding, alongside the TIG. I definitely get prettier results and more control with the TIG, but when working with larger cross-sections, the speed and quantity of weld available with SMAW, as well as the low cost of consumables, is nice to have. I wonder if the same might be true of having MIG alongside the TIG?


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## awake (Apr 2, 2020)

Brian, looks to me like that fixture should work. Only thing I would suggest is whether you could hold it more securely in the vise if you turn it 90 degrees.


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## a41capt (Apr 2, 2020)

I like your method for spacing during the crankshaft pressing Brian.  Knurling come in handy when stock doesn’t fit for crap!

Many, many moons ago, when I was a young flat track racer, the Harley KR I was riding developed excessive piston slap while out of town.  We knurled the piston skirts by sandwiching them between two coarse files in a vise, gave it the tiniest bit of a squeeze, and then alternated tapping on the opposing files (causing the piston to rotate) until the entire skirt raised up a rough couple thou. knurl.  Got me through the race!

John W


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## werowance (Apr 2, 2020)

so those 45 slots,  are those going to be to create cooling fins or fan blades built into the flywheels?  if so how will you cut the internal slots on the inside of the outer flywheel ring?


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## werowance (Apr 2, 2020)

and on that,  will the fins of the 2 flywheels be pulling the air in a single direction like this 
--> , -->

or will it be pushing from both sides in or both sides out like this --> , <--  or opposite direction
<-- , -->


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## Brian Rupnow (Apr 2, 2020)

Pulling the air in a single direction.


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## Brian Rupnow (Apr 2, 2020)

And that, my friends, is slicker than whale poop!! Here you see one of the finished hubs by itself, and with a nice blade array using a bunch of my parallels. I just wish I had a 1/8" wide slitting sawblade. This was made using a 1/16" saw blade, but I had to go around once to make the slots 1/16", then around once with the blade offset 1/32" then again with the sawblade offset the other way by 1/32". This was far less work than I anticipated. I will make the second hub tomorrow.


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## Brian Rupnow (Apr 2, 2020)

Werowance--There won't be any slots in the outer rim. The blades fit flush to the inside of the rim and are tig welded.


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## Brian Rupnow (Apr 3, 2020)

This morning I put on my mask ,Purelled my hands, and drove to my metal suppliers who had set my material outside their door. Collected my material, Purelled my hands again, wiped down my trucks steering wheel with antiseptic wipes, and drove home again. Got home, washed my hands for 30 seconds with warm water and dishsoap. My hands have never been this clean. I look goofy wearing a mask. The 1" x 1/8" cold rolled flatbar is exactly what I asked for. The tube is 6" o.d. but the wall is only 7/16", not the 9/16" that I had wanted, but it will do. I could die of old age before my bandsaw would cut thru that pipe, so I will part off "rings" of material 3/4" long. I think I will weld a flatbar across one end with a hole for a live center and hold the other end in my lathe chuck with reversed jaws. You can't cut all the way thru in the lathe or bad things will happen. DAMHIKT. You can however, cut almost thru and then complete the cut on the bandsaw. This was the last material I will require to build this engine, and by the time I buy a set of ignition points and a condenser, it's going to get very close to the $200 mark. The steady-rest is which came with my lathe is way too small to use--looks like it will only open up enough to take 3" diameter stock.


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## awake (Apr 3, 2020)

Brian, I do have one concern about your plan - I would recommend against using parallels for the fan blades. Not only are they expensive, but the hard steel may not respond well in welding with the mild steel.

Oh, wait - you _weren't_ planning on using the parallels? Never mind, then.


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## Brian Rupnow (Apr 4, 2020)

I'm thinking forward to the next steps in this flywheel fabrication exercise. In a perfect world, I can hold the outside rim (6" tube parted off to 3/4" wide)  in my lathe 3 jaw chuck. I can slide the hub (with slots) over a piece of 1/2" cold rolled steel and hold it in my tailstock chuck. This will guarantee absolute concentricity. I could then cut the flatbar  "fan blades" to a perfect precision fit between the hub and the outer rim. Then tackweld both ends of the flatbar to the hub and the outer rim.---This sounds good, but their are some fairly sophisticated controls in the electrics of my lathe, and I think that any kind of electric welding would probably damage my lathes circuitry.----Or---I can counterbore a  1 1/2" hole into a large piece of 6" wide aluminum flatbar and in the same set-up counterbore a 6" diameter recess to center the outer flywheel rim. Have to think some more on that, because the blades are the full 3/4" depth of the hub and outer rim. I don't have a piece of 6" wide aluminum anyways, and I am not going to venture out into "virus country" again. I do have a 10" faceplate which I might be able to do something with. Any good suggestions will be entertained---


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## dsage (Apr 4, 2020)

Brian Rupnow said:


> I'm thinking forward to the next steps in this flywheel fabrication exercise. In a perfect world, I can hold the outside rim (6" tube parted off to 3/4" wide)  in my lathe 3 jaw chuck. I can slide the hub (with slots) over a piece of 1/2" cold



Brian:
Could you JB Weld tack the pieces together while it's in the lathe. Don't put the JB weld in the slots. Maybe just at the ends so it can be easily cleaned off.
Then carefully take it out of the lathe in once piece.
Then tack it with the welder - just tack it until it's all tacked together.
Then scrape off the JB weld and finally weld it up.
That would allow you to free it from the lathe in one piece while you properly weld it.

Of course it's probably going to warp quite a bit when you weld it but......


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## Brian Rupnow (Apr 4, 2020)

dsage---thank you for the suggestion. 
Okay---I'm having an idea. If I mount my faceplate on the lathe, then I can use 1/2" hex bolts thru the existing slots and use a dial indicator to center the outer rim perfectly on the faceplate.---Then dismount the faceplate from the lathe, and turn a center spigot that is a precision fit into the faceplate center hole, with a 1/2" diameter nose on it to fit the hub onto.


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## Brian Rupnow (Apr 4, 2020)

This would let me mount the hub on the turned center spigot, and the outer rim and hub would be perfectly concentric. Then I can fit the "blades" into place and get a decent tack on each one. This method allows me to do any welding or tacking with the faceplate dismounted from the lathe completely.


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## a41capt (Apr 4, 2020)

Brian,

how about if you remove the chuck from your lathe and use it as a fixture for tack welding? The reason I suggest welding away from your lathe is that your TIG welder will initiate its DC arc with a high frequency pulse that can be VERY harmful to electronic devices. When I’m welding, I run a secondary ground to my worktable and machine, and remove all electronic devices from the area (cellphone, etc.).

This is why I can never have a pacemaker. How the hell can I ever quit welding?

John W


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## Brian Rupnow (Apr 4, 2020)

John-read post 167 carefully.


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## Brian Rupnow (Apr 4, 2020)

That worked out very well. A lot of moaning and groaning from the lathe, occasional shots of cutting oil, and a very slow advance. I left about 1/16" wall which I will cut with my bandsaw.


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## a41capt (Apr 4, 2020)

Brian Rupnow said:


> John-read post 167 carefully.


Oops, you beat me to it!

John W


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## Brian Rupnow (Apr 4, 2020)

And that is about as far as I'm going to take things today. Tomorrow I will work on getting things all set up on my faceplate.


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## Brian Rupnow (Apr 4, 2020)

-I don't think I will use any continuous welds. This flywheel is self contained and the radial forces will all concentrate on the outer rim. Too much weld will distort things. For now I am considering a weld on each side of the blades where they contact the hub, and a weld on each side where the blades contact the rim. So, each individual blade will only have four small welds, one at each of the four corners of the blade.


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## a41capt (Apr 4, 2020)

I think that’s a wise choice Brian.

Distortion of the blades is very possible, and there goes all of your hard work and accurate machine setups.  Since there’s almost no load on the fan blades, the stresses involved will be minimal, and a secure tack weld at the leading and trailing edges of each blade, and on each end should prove more than adequate for your needs.

if the blades are inset from the outer rim, thereby making your weld a bit of a reach with the TIG torch, don’t be stingy with the argon.  The gas stream/cup/flow is what stabilizes your arc, and it’ll ensure that your arc doesn’t wander and mar the finish on the rim and/or blade.

Best of luck, this is a unique set of “turbines” you’re building!

John W


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## a41capt (Apr 4, 2020)

Oh, one more thing I’ve learned the hard way.  Even though you didn’t mention it for this setup, never use a strong magnet to secure/align parts for TIG welding, even outside of the weld area.  I got lazy one day and thought I’d give that a try, and what a complete wreck that turned out to be!!!  Magnetic fields play havoc with a TIG arc... 

Cheers!
John W


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## Brian Rupnow (Apr 4, 2020)

Thanks John--I have experienced the "magnet thing" with my MIG welder. I have a couple of large "corner magnets" here, intended for making corners in fabricated plate-work. They work okay for laying in tack welds, but they do distort the arc if you try to do a continuous bead with the magnets in place.


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## awake (Apr 4, 2020)

Brian, here's an alternative that I would consider - mount a piece of plywood to your faceplate; turn a recess in it, maybe 1/4" deep, 6" wide so the outer rim just fits snugly. Drill or bore or whatever is needed to mount the inner hub.

Yes, plywood does not seem like the obvious choice when welding, and yes, it will char ... eventually. But by the time you've got one side tacked together, it will have served its purpose and can be discarded.

The one major drawback with this idea is that you will have to clamp the ground directly to the rim. But it avoids using your precision equipment (lathe chuck or faceplate or so on) as a welding fixture.

Note that, in addition to the issue of the electronics in your lathe, welding on a lathe can be a particularly bad idea if you do not provide a direct path to ground. If the ground circuit goes through the lathe bearings ... bye, bye bearings!


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## Peter Twissell (Apr 5, 2020)

I'm not so sure that loads on those blades are as small as might be imagined.
The purpose of the flywheels is to keep the engine turning between power strokes. At each power stroke, there is a large torque pulse accelerating the flywheel. If the blades are not a tight fit in the slots in the hub, the welds will be stressed and will fatigue.


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## Brian Rupnow (Apr 5, 2020)

I guess we'll find out.


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## awake (Apr 5, 2020)

Just stand well back when you run up the speed!


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## Brian Rupnow (Apr 5, 2020)

In my effort to "avoid the virus" I'm trying to not to go out anywhere to buy more material. I had one big cube of aluminum 3" square, so today I set it up in my lathes 4 jaw and turned three diameters  on it, all in one set-up. One diameter is a "precision fit" into the faceplate mounting hole, one is a precision fit into the 1/2" bore inner flywheel hub, and the third diameter is slightly larger than the hole in the faceplate to keep the plug from "pulling through" the faceplate. The small diameter is drilled and tapped on center for a 5/16" bolt, which holds the inner flywheel hub tight against the faceplate. I'm not a huge fan of setting things up in my 4 jaw, but I can do it when I need to.


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## teeleevs (Apr 5, 2020)

Brian Rupnow said:


> I'm thinking forward to the next steps in this flywheel fabrication exercise. In a perfect world, I can hold the outside rim (6" tube parted off to 3/4" wide)  in my lathe 3 jaw chuck. I can slide the hub (with slots) over a piece of 1/2" cold rolled steel and hold it in my tailstock chuck. This will guarantee absolute concentricity. I could then cut the flatbar  "fan blades" to a perfect precision fit between the hub and the outer rim. Then tackweld both ends of the flatbar to the hub and the outer rim.---This sounds good, but their are some fairly sophisticated controls in the electrics of my lathe, and I think that any kind of electric welding would probably damage my lathes circuitry.----Or---I can counterbore a  1 1/2" hole into a large piece of 6" wide aluminum flatbar and in the same set-up counterbore a 6" diameter recess to center the outer flywheel rim. Have to think some more on that, because the blades are the full 3/4" depth of the hub and outer rim. I don't have a piece of 6" wide aluminum anyways, and I am not going to venture out into "virus country" again. I do have a 10" faceplate which I might be able to do something with. Any good suggestions will be entertained---


I would make the fan blades a little over size, weld them into the hubs, then turn the outside diameter to a snug fit for the outer rim. I've had a little experience with fan blades, they need to be curved like the top of an airplane wing to work really efficiently but that may not be needed in this case, would complicate assembly a little.


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## Brian Rupnow (Apr 5, 2020)

teeleeves--That works if the "blades" are strong enough not to deflect when you try to machine the tips. These blades, when attached to the hubs, will stick out 2" unsupported. I don't think they would machine cleanly because they are only 1" x 1/8" material and will deflect rather than be clearly cut. It did cross my mind that I could do what you are saying if I used a toolpost grinder, but I don't have one.


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## Brian Rupnow (Apr 6, 2020)

This didn't go quite as I had planned, but it was very close. I was having trouble getting the rim centered, so I made up a disc with a reamed 1/2" center hole and an outer diameter that was a precision fit into the flywheel outer rim. I put a piece of cold rolled 1/2" diameter in the tailstock chuck, mounted my centering plate on that, set the flywheel rim over the centering plate, then cranked it in flush against the faceplate. I had to make up a couple of "grip plates" to hold the outer rim in place. After I was done, I backed the tailstock and centering plate away and checked the inner diameter with a dial indicator. It had a total indicated run-out of about 0.040" so I spent a half hour tappy tappy tapping on the rim until the best reading I could get was about .015" total indicated runout. The outside and inside of this piece of tube has never been machined so I'm not certain how concentric the inner and outer diameters are. The next step will be to dismount the faceplate from the lathe with the outer flywheel rim still in place, then use the fixture I machined yesterday to hold the flywheel hub perfectly centered. Then I start cutting the "vanes" to length. In a perfect world, the vanes would all be exactly the same length, but it seldom works out that simple.


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## Brian Rupnow (Apr 7, 2020)

One last and final concentricity test before I start cutting "blades". I have this "sweep indicator" that I seldom use, but this is a set-up that best suits it. First sweep the hole in the center of the faceplate and move the mill bed until I get a zero reading all the way 360 degrees around the faceplate hole. Then move the "finger" up to the inside diameter of the tube and sweep again, tapping the tube a little bit this way, a little bit that way, until I get a zero reading on a full 360 degree sweep. Good to go now, today I will cut blades to suit.  Unfortunately, the 1" blade width, as purchased is just a bit wide. I have to take about .035" off one side to get the exact width so that the blade will not extend out beyond the edges of the hub. I will probably put all 6 blades in the mill vice and mill them all at the same time. I have been doing everything I can in the machine shop, where it is warm, but I can't put the welding chore of any longer. So--later this afternoon or maybe tomorrow morning, I will move my act out into the garage. I am going to make up about 10 different "practice weldments " until I get some experience with my new TIG, and then I will tackle the flywheel.


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## awake (Apr 7, 2020)

Crossing my fingers and holding my breath for good results ...


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## a41capt (Apr 7, 2020)

Quite a setup Brian.   Awaiting the results and keeping my fingers crossed!!!

looking forward to your success,
John W


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## Brian Rupnow (Apr 7, 2020)

So, after almost a full day dicking around and getting things as perfect as I can, we have number 1 flywheel ready to weld. I have tried to space things out so that the warmer weather got here before the need to weld. It was 58 degrees F here today, which is not exactly as warm as I would have liked, but you work with what you've got. You will notice that the corners of the fan blades have all been chamfered about 3/32" x 45 degrees. That gives me room for a little bit of filler rod, without any of it sticking out past the edge of the flywheel. So---Tomorrow morning I practice my tig welding, tomorrow afternoon I weld the first flywheel. Wish me luck!!---Brian


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## a41capt (Apr 7, 2020)

Looks great!


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## Brian Rupnow (Apr 8, 2020)

YOWZAHH!!!--I tig welded something!! Okay, I know it isn't impressive, but it is my first weld with my new tig welder. The documentation and instructions that come with this unit are worse than horrible. It's not Chinglish, but whoever wrote it, English was certainly not their mother language. The two actual "welds" are fusion welds at 125 Amps, with a 3/32" 2% thoriated tungsten. No filler rod was used.  I have already figured out that I don't care for the foot pedal control. My machine has a "high tension start" function, with a push button on the actual torch head to start the arc going. I am amazed at how hot the arc gets, so quickly. I have been watching "How to tig weld" videos from Weld.com, and they are very informative and well done. I have also started a binder in which I write down everything  I learn or discover about the tig welding process. I think I need more than half a days practice before welding anything that is going to be visible, like the flywheel/fan blades. I had hoped to get more practice in tomorrow, but the high temperature for the day is going to be only 2 degrees Celsius. I don't want to freeze to death learning to tig weld.


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## Brian Rupnow (Apr 8, 2020)

This morning was the first time I actually installed all of the required hoses and lines to the welder. The damned thing is like an octopus. I spent the rest of the morning fabricating even more brackets on the welding cart to hold all the various wires and hoses. Then I went for my walk, then I actually dared a practice session with the welder. The weld you see was done at 125 amps and bypassing the foot pedal, which would have been fine with my old Lincoln buzz box stick welder, but seemed unreasonably hot with the tig. At a full 125 amps, everything gets so hot so quickly that it is scary. I realize that if I had the foot pedal hooked up I could ease up on it and cut the amps down to a more controllable level. Learning--learning--


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## a41capt (Apr 8, 2020)

Repeat after me, the foot pedal is your friend....  Now go write it on the chalkboard 100 times!   

But seriously, infinite heat control right at the tip of your, er, foot.  Wait’ll you start on aluminum, and that heat runs away faster than the population of Tokyo staying out of the reach of Godzilla!

Stay warm,
John W


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## Brian Rupnow (Apr 9, 2020)

This morning I made a run for it---Put on my mask, Purelled my hands, and drove to the wine store.---Wine store was closed. Decided to get points and condenser for the new engine, went to PartSource, and it was closed. I have conflicting information about tig welding. One YouTube spot has a man saying how very important it is to wear gloves to protect your hands from harmful rays. Another YouTube site has guys with bare arms covered in tatoos  giving instruction on how to tig weld. Having suffered some bad ray burns from arc welding in a tee shirt, in my youth, I decided to stop at my welding store and buy some tig gloves. Gasoline is cheaper right now than it has been in 20 years, so I filled up my truck with gas.---$53 to fill the tank.--It usually costs about $88.  I don't feel a lot like working today, so other than a bit of tig practice I'm going to have a lazy day. Good wife has decided to accompany me on my "Fat mans walk" now that all the glaciers have retreated from my wood trails across the road. She took this picture of me yesterday on our walk.


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## awake (Apr 9, 2020)

I'm with John - you want to start using the foot pedal right away. I thought it would be a lengthy learning curve, but I found that it somehow seems absolutely natural, almost instinctive ... up to a point. On my previous machine, the foot pedal was always 0 - 200 amps; on my new machine, the pedal is 0 - 100% of the amperage dialed in on the front panel. The latter is way, way, WAY better. I had long thought about adding a potentiometer to my old foot pedal to let me achieve a similar result - now I wish I had done so.


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## a41capt (Apr 9, 2020)

Brian, it’s good to get out of the house, and as my Mom used to say, “get the stink blown off of you!”  I too live in a rural setting and enjoy getting outside, riding my trials motorcycle around my property, and doing some chores.  Unlike you, my weather is almost always tenable.  My part of Arizona has about 330 days of sunshine per year.

Awake, I went to TIG welding school in the Navy (Air Rework Facility, North Island NAS, San Diego) many, many years ago.  We used Lincoln IdealArc 300 amp welders with fixed high frequency (60 hz) and you’re right, the pedal and capabilities were NOTHING like my new machine with its incredible range of features.  BTW, my unofficial final exam for graduation from the Navy training program?  Butt weld two sheets of aluminum foil.  Even with my NEW machine, with my old eyes I don’t think I can pull that one off anymore!

John W


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## awake (Apr 9, 2020)

I can't even blame my eyes - though they are definitely getting old - I'm pretty sure I will never achieve an aluminum foil weld!! I was really proud of myself when I finally managed, with the help of the new machine, to weld a bandsaw blade without blowing out holes.


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## dsage (Apr 10, 2020)

Brian:
Get over it and use the pedal. With TIG (unlike MIG) you need some variability in the current. It's key to controlling the weld pool. As the metal heats up on a long weld you WILL have to throttle back or the weld will get out of control.
It's also useful to throttle back when you get to the edge of a piece (like the edges of your fins) so they don't melt away.
Also you need to throttle back and fill at the end of a weld so you don't leave a crater. Which can result in a crack.
You'll find this out most when you start welding aluminum.

Yes fully cover up exposed skin. I once got a burned upper chest (below the neck) from welding in a T-shirt. Nasty. And your hands are tough but will get "sun burned". The gloves are also useful when you have to push parts around while they're hot.
Good TIG gloves are very thin and supple to give you fine control of the filler.
Lots and lots of practice required.


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## Shopgeezer (Apr 11, 2020)

I guess I should take all this advice to heart and attach the foot pedal to my new machine. It is a stick/tig/plasma machine and works very well in all modes. I just find that focusing on what my hands are doing while tig welding doesn’t leave enough brain cells available to add foot action. Oh well, lots of practice needed.


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## awake (Apr 11, 2020)

Shopgeezer, when I first started doing TIG, I worried about trying to coordinate my foot along with my hands - it seemed like one more thing to have to keep track of.

What I found was that I didn't have to think about it - or at least, hardly ever think specifically about it. It seems to work very naturally and instinctively - or rather than "instinctively," probably some sort of muscle memory related to driving for the last 45 years. Just like pressing the gas pedal on the car, I don't think about doing it - when I need to speed up or slow down, I just do it.

I hope that will be your experience as well!


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## Brian Rupnow (Apr 11, 2020)

The music never stops---TIG practice is going slowly. I decided that I had sufficient material to make up a fixture to hold the second flywheel/fan for welding, so I did. There is a fellow one of my forums calling himself "Tungsten Dipper". Lets just say that with my TIG progress, I have a full understanding of his name now!!


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## awake (Apr 11, 2020)

Brian, one thing that I find helpful with TIG welding is to get my face close, far closer than I would for stick welding. I am both nearsighted and have presbyopia, but I find that I can see better if I take my glasses off and get up close. Others talk about using magnifying lenses in their welding hoods - I've tried one, but never got it to where I thought it was helpful.

Oh, another thought - when it comes to tacking those blades in place, you might use "flash tacks" - relatively high amperage, electrode positioned very close to (< 1/16" from) the joint, good sharp electrode, no filler. Get it positioned, then get on and off full pedal - maybe 1/3 of a second total, if that much. What you are after is a quick burst that creates a very small fusion tack.


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## Brian Rupnow (Apr 11, 2020)

You just want me to set my beard on fire, dontcha. 
Todays message concerns ergonomics. I find that if I hold the tig torch in my right hand, I can run a decent bead IF I brace my right wrist with my left hand. That is fine for running a bead with no filler rod, but when holding filler rod in my left hand, my right hand shakes like a toad eating chain lightning.---So, back for a closer look at the Youtube videos.--Ah Ha--The good videos shown by weld.com shows the instructor working with a much higher table, on which he can rest his right wrist. I wasn't about to build a higher table, but since I am in "learning mode", I can make my existing table a little higher. That is what you see here. A temporary "table riser" made from a few pieces of 2" x 8". This raises the height of my work area 6 1/2" higher than the original table top. Now  I can hold the torch steady by bracing my right wrist on the temporary table top while my left hand holds the filler rod.


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## awake (Apr 11, 2020)

Hmm, hadn't thought about the proximity of the beard to the arc - maybe that's not such a good idea after all!

Definitely you want to have some way of bracing your hand - whenever I watch Jody on Tips and Tricks, he always makes practice passes, emulating how his hand will move throughout the bead, and adjusting if it is not going to be possible to move smoothly. I try to do the same ...


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## Brian Rupnow (Apr 12, 2020)

I just finished what may be the last bit of machining for Thumper. This is the starter hub which bolts to one of the flywheels. As of right now I have no excuse to keep me away from my new TIG welder.


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## a41capt (Apr 12, 2020)

I use the “TIG Finger” over my lightweight glove on my torch hand (right hand for me) to keep me from flinching due to heat build up when bracing my torch hand on the weld piece.  No more burns while getting that last bit of bead done, and on aluminum, the heat travels to your hand real fast!

Here’s a link to the one I use, but there are many others:








						TIG Finger - Must Have for Every TIG Welder!
					

A Must-Have for Every TIG Welder (Select Size From Drop Down Menu Above) This is a nifty little product that solves a common problem when TIG welding, your fingers get really hot and if you touch down, you end up ruining your expensive gloves! Patented sleeve design made of super...



					www.arc-zone.com
				




John W


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## Brian Rupnow (Apr 12, 2020)

I've seen those advertised, but haven't gotten into this tig weld thing to need one yet.


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## Brian Rupnow (Apr 12, 2020)

The new tig welder calls for a lot of coordination. Hold the tungsten 1/8" off the surface of the steel, move your hand at a constant speed, and hold the foot pedal down as far as it will go. If the tungsten touches the puddle of molten metal, then you have to stop and remove the tungsten and regrind the point on it. If your hand doesn't move at a constant speed, the width of the melted area changes (you want the width to be constant). If you let up on the foot pedal, the arc goes out. These were all done with no filler rod. The plate is 304 stainless (because that is what I had).  I did a few welds with filler rod, and the most surprising thing for me is how quickly this thing eats filler rod. It consumes filler rod at least twice as fast as oxy acetylene welding.


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## a41capt (Apr 12, 2020)

Brian,

Your arc shouldn’t quit because you let up on the pedal, it should only get a bit colder. Make sure your setup is correct, and check that you’re set for a tad bit more amperage than you need. To initiate the puddle, you’ll need a bit more heat, but you’ll throttle it back as soon as she starts to run.

The only reason for it to use more filler rod than gas welding is either over penetration or too big of a puddle.

DC welding will come pretty quick to you if you’re a decent gas welder. It’s all about developing a rhythm and watching the arc closely.

BTW, if you dip your tungsten while practicing, it’s not the end of the world. As long as you haven’t grown a blob on the end it’s okay to keep going. A contaminated practice weld doesn’t need to pass X-Ray...

John W


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## Brian Rupnow (Apr 14, 2020)

Today was practice running weld beads, using filler wire. Trying different amperage settings and travel speeds. I was concerned that perhaps I wouldn't be able to use this welder, because I couldn't see the arc puddle clearly enough. Found out today that with a higher amperage comes a larger molten weld puddle and it all becomes easier to see. I did order a set of pyrex clear glass welding cups--they don't directly make you a better welder, but they allow you to see much more of what is actually happening. I am, as I said before, amazed at how quickly these welders consume welding rod, compared to oxy acetylene.


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## dsage (Apr 14, 2020)

Well. I'd say it uses a lot of filler because you're making a pretty huge bead. 
If you really want a bead that big user thicker filler.
The amperage setting rule of thumb (as a start) is 1 amp per thou of material thickness. That's where amperage should be set. Not set to suit your ability to see  
Does your welding helmet have a darkness setting? If you're having trouble seeing turn it brighter. 
The darkness setting (as I understand it) has nothing to do with the safety of using it. There is a filter before the darkness device that  filters out all the harmful rays. So it's safe to turn the brightness up until you can see. My helmet only goes as low as 10 but I'd like it to go brighter.
You may find it useful to put a bright light on your work as well. I usually weld with the garage door open and the sun coming in helps the visibility.


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## Brian Rupnow (Apr 14, 2020)

I am using a #5 cup and the tungsten is sticking out 5/16" past the cup end. Running about 12 to 15 cubic feet of argon per minute.(or hour, not sure which). I have my helmet set at level #9 sometimes at #10. I know about cheater lenses for inside the helmet, but after my eye surgery last year my eyesight is pretty good, and I am wearing my glasses under my welding helmet. I am using a 3/32" tungsten and 3/32" rod  The rod is ER70S-2 and the tungsten is 2% thoriated #2PC332.


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## dsage (Apr 14, 2020)

That all sounds about right.
How about the material thickness and current setting?
Using the pedal ?


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## Brian Rupnow (Apr 14, 2020)

I have been working with different current ranges to see what effect it has on the weld. Rule of thumb seems to be 1 amp per one thousandth of material thickness. I'm still gaining experience with the pedal.


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## awake (Apr 15, 2020)

A couple of thoughts. I'll be the first to admit that I am a long, long way from any expertise when it comes to choosing which cup to use, but as I understand it,  a #5 cup is pretty small for ordinary work using 3/32" rods and filler. You might want to experiment with something like a #7 and see what difference that makes - though that also means using a bit more argon.

I'll echo Dave that those are really, really large beads for TIG welding. At first I wondered if you might be running hot on the current, and feeding in extra rod to compensate ... but I noticed that at least a couple of those beads look like they are sitting up on the surface a good bit, suggesting that you may be cooling the puddle too much by feeding too much rod, and therefore getting low penetration.

Final thought: if you buy any more electrodes, consider going with 2% lanthanated rather than the thoriated. My reason has less to do with the radioactivity of the latter, and more to do with the fact that the lanthanated electrodes can handle both the DC and the AC - no need to switch to a pure tungsten electrode, or to keep different sets of electrodes on hand.


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## ALEX1952 (Apr 16, 2020)

Try a visit to this sight for what I believe to be very good well explained tutorials :-http://www.weldingtipsandtricks.com/


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## Brian Rupnow (Apr 16, 2020)

This morning I put on my mask and my gloves and my iron underwear, and went over to my welding supplier to pick up some 1/16" tungsten and some 1/16" filler rods.  Prepaid by phone to avoid any close contact, material was left for me in vestibule. Came home and wiped everything down with varsol, then washed my hands with dish soap and hot water for 30 seconds. What a giant pain in the arse!!--At any rate, I wanted to see how the tig welder works with a smaller rod and tungsten.  I have shown myself that I can lay down a bead with 3/32" tungsten and rod, even if the bead is large and ugly. I have cut up a bunch of 1" x 1/8" flat stock and prepared it in the same manner as the blades in my flywheel/fan. I made a cheap and nasty fixture to hold all of these pieces beside a larger piece of steel, in the same relationship as the fan blades, and will practice later today with the smaller rod.


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## dsage (Apr 17, 2020)

Brian:
Have you tried the lay-wire technique? It is a valid way to weld.
Just lay the filler flat on the surface (or in the joint) and run over it with the torch melding the filler and the base metal until the bead is just slightly proud of the surfaced. This will avoid the ability to add too much filler.

Set the maximum pedal to maybe 90 - 120 amps at full throttle for your 1/8 material.
Keep the tungsten very close to the work. 

BTW
I assume you are grinding the metal very clean. TIG is very un-forgiving on dirty metal. Wipe it with acetone as well.


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## Brian Rupnow (Apr 17, 2020)

Today I welded up one of the flywheel fans. Let me be the first to say its uglier than original sin!! However, I haven't done any clean up on it yet.  I've welded it in all of the spots (4 per blade,) that I intended to. I didn't melt anything away, although I probably added three times as much filler rod as I needed to at every spot. There seems to be only micro-seconds between having the metal molten enough to 'merge' with the filler weld and so hot that you burn away the fan-blade. I tried it with a 1/16" tungsten and filler rod at 70 amps max and with 3/32" tungsten and filler rod at 115 amps max.  I am dazzled by how quickly everything happens. Back in the day, I did a lot of oxy-acetylene welding, and since I controlled the torch, things only happened as fast as I wanted them to. With this TIG process, it keeps wanting to run away on me. It gets so hot, so quickly, and gets molten so quickly that I'm afraid I'm going to melt everything before I get a chance to add any filler rod. Next step will be to clean everything up and decide if I want to add any more weld anywhere.


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## dsage (Apr 17, 2020)

Is your pedal working??
Because if you throttle back on the pedal you should be able to get the amps back to nothing and barely have an arc.
The pedal should control from zero to whatever you have dialed in as maximum.
 Down to the point nothing melts and the little arc just sits there at the end of the tungsten.
 Sounds to me like something is wrong. Certainly nothing should be "running away from you".
Also there should be no clean up required. Tig welds are very clean right off the torch.


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## awake (Apr 17, 2020)

Brian, I'm with dsage. Make sure the "minimum" setting on your pedal is turned down to 0.


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## dsage (Apr 17, 2020)

Andy. I have an old analog machine that's always zero at minimum pedal.
Dang fancy new machines have too many variables .
Nice to know. Thanks.
But yes. I can sit with a tiny little sparkle at the end of the tungsten that barely heats anything. Something has to wrong there.


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## awake (Apr 17, 2020)

Dave, it may have been on the other forum that Brian showed a picture of his pedal. I've never seen one like it - he has two potentiometers on it, one to set the minimum setting and one to set the maximum setting. I've seen pedals with a potentiometer to set the max - a less convenient option than being able to dial it in on the machine itself, but better than nothing. This is the first time I have seen a second pot to set the min, and I still can't figure out why that would be useful.

I've got a brand new semi-digital machine with lots of bells and whistles - semi-digital meaning that it uses digital controls internally, but analog knobs to set the settings - but like yours, minimum pedal always equals zero amps!

On edit: see reply # 172 in this thread for a picture of the footpedal: Thumper--a new 1 3/8" bore i.c. engine


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## Brian Rupnow (Apr 17, 2020)

I sat around after my welding, trying to analyse what was happening. I decided that it must have been the foot pedal. It wasn't the fault of the pedal. It was just the way I was using it. Ran things with the pedal "on the floor".  Tomorrow I will try some welding with more of my attention on what position I am holding the pedal in.


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## awake (Apr 17, 2020)

Brian, I would recommend spending a bit of time practicing just with the foot pedal and the arc - you should, as Dave says above, be able to go from a tiny firefly to a high-power arc and back again, and anywhere in between. If this doesn't work, I'd start to suspect that something is wrong with your machine.


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## Brian Rupnow (Apr 18, 2020)

-I needed a bit of filler rod. All of the "blades" had a 3/32" x 45 degree chamfer on them. This was so I could fill the chamfer with filler rod, and then when I cleaned everything up afterwards I could be certain that all of the blades were indeed still welded. I have cleaned the first flywheel up on the lathe and mounted it, along with the starter ring on the engine. I am very happy with the size and proportions.  I think that after the second flywheel is welded, that I may paint both flywheels and just leave the outer diameter unpainted.


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## a41capt (Apr 18, 2020)

Looks good Brian, can’t wait to hear the first pop!

John W


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## dsage (Apr 19, 2020)

That looks good  !!
Maybe -- if you care to and it actually needs it -- a little grinding with a dremel and a bit of body work and paint on the spokes and inner ring and you can gussy it up.
It's getting there


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## Brian Rupnow (Apr 19, 2020)

It's too cold and damp to work out in the main garage with my tig welder today. So--Just to keep things moving forward, we install ignition points today. There was no need to dismantle the engine to add these two tapped holes. I have a big old cast iron angle plate that lets me bolt the angle plate to the mill bed and clamp the fully assembled engine to the angle plate. With the end of the crankshaft sticking up past the plate, it is great to have some extra long drills and taps. I will find a spot to attach the condenser while I am still in this set-up. The points will be hidden in behind the flywheel. Not exactly sure about the condenser location, but will find out in the next half hour.


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## awake (Apr 19, 2020)

Brian, looks like your flywheel came out well. How's the balance on it? Eager to see and hear it run!


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## Brian Rupnow (Apr 19, 2020)

Andy---Near as I can tell from a static balance, the flywheel is fine. 
The condenser was just a tad to big to fit behind the flywheel, so I moved it's location around to the end of the sideplate. And that is the sum total of the electrical components for this engine. Nothing left now except for the second flywheel. I just got back from my "fat mans walk" with my good wife, and we got rained on! I judge that I've got about 1 week of entertainment left on this engine, and then I may go stark raving mad. I've been entertained by this engine thru March and April, so that has given me something to do. I will definitely need a few weeks away from machining. This down time between builds is generally when my wife and I took time for each other and our grandkids. Now with this virus business, you can't really go and visit friends and you can't do things with grandchildren.


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## William May (Apr 19, 2020)

This looks like an awesome little engine. Put me down for a set of plans!
P.S.  Our icicles have a Polar Bear attached to the other end. Just saying!


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## Brian Rupnow (Apr 20, 2020)

When I design and build these engines, I don't make an assembly drawing, only parts details---I work directly from the cad assembly on my computer. Of course when I decide it's time to sell plans, then I need to make complete assembly drawings so people who buy them know how to assemble them. The plans are never sold before the engine works to my satisfaction. I needed some quiet time this morning while my wife sleeps, so I've went ahead and made assembly drawings.---Brian


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## Brian Rupnow (Apr 20, 2020)

And more of the same---


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## wthomas (Apr 20, 2020)

Hi Brian:
     On welding the fins, let me tell you how I was able to get run a .020" bead on the side of a mild steel block.
I was trying to weld the smallest spring wire I could purchase (.008") for a job.  I never was able to do it but like
I said I did get the weld bead down to a .020" by shutting off the  high freg. and just cracking the amp. control
so that the led indicated it was on and using a .020" Tung.,  Then using a bright light shining on the work so I could
see the work I carefully put the peddle to the metal on the foot peddle and slowly brought the tung. toward the edge
of the work till I got an arc.  I then was able to work the puddle down the edge of the part.
     I think if you work the heat like you did with a torch starting low and working up you will have a whole different
weld.  The main reason, I think, is that the tig welder gives instant heat and if you use the higher amp they recommend
for a material thickness that is enough heat to go all the way through the material.  Welding the fins from both sides,
I think, only needs half as much because you are only welding one half the thickness of the metal.  Just my 2 cents.
(Not worth much these days)
                                                                           Bill Thomas  
                                                                                                    Stuck inside in Michigan, USA


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## Brian Rupnow (Apr 20, 2020)

Thank you Bill Thomas.---I really do get the part about "Stuck inside".


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## wthomas (Apr 20, 2020)

Hi Brian:
     Just sitting around thinking about you welding today.  You said earlier about not needed a tig torch to build the engine.
I have been thinking about how you would Silver Solder the flywheel to make it strong enough and safe.  If you have not tig
welded the second flywheel have you though about how you could Silver Soldering it together.  You have it fixtured  good
so you could run a fillet bead each side of the blade with a small Acy torch.  Just thinking while stuck inside.
                              Bill Thomas


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## Brian Rupnow (Apr 20, 2020)

Bill--the biggest problem with welding the blades using oxy-acetylene would have been distortion of the metal. Wobbling flywheels show up big time in videos. There was some distortion from the tig welding. I had the inner hub and outer ring fixtured perfectly, but still got some heat distortion. I think that when I mounted the flywheel on a 1/2" shaft with the shaft in my lathes 3 jaw chuck I had about .017" distortion on the sides of the outer rim and about .015 on the outer diameter. I cleaned up both sides and the o.d. so that the flywheel runs perfectly true now.  The biggest issue would have been adding enough heat into that outer rim to get silver solder or brazing flowing on it. I like my mig welder, but its almost impossible to get a bead that is pretty enough on small items without having to resort to filing and sanding and grinding. I've been thinking of buying a tig welder for a couple of years now, and these strange flywheel/fans gave me an excuse to buy one.


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## Brian Rupnow (Apr 20, 2020)

I wanted to buy a spray can of John Deere green today for the flywheels, gas tank, and rocker support, but the hardware store is closed because of Covid. I wanted to practice some more tig welding today, with special attention given to the foot-pedal, but it was too cold in my main garage. I wanted to take a longer "fat mans walk" but I've got bad arthritis in my left knee. I wanted to go see my grandkids, but I can't because wife and I are "social distancing". All in all, I haven't done a hell of a lot today except cruise the internet and read the forums.  I've had a very much "useless old man day"!!!


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## awake (Apr 21, 2020)

Sometimes you just have to realize that a particular day is _not_ going to turn out the way you planned ...


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## petertha (Apr 21, 2020)

I don't have a TIG (yet) my only experience was a course at local technology college. We wiped the rods & certain alloys with acetone. Maybe a more experienced welder can chime in but varsol might be a little on the oily side & anything like that can cause issues. The instructor mentioned that specifically. Acetone evaporates almost immediately on contact.


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## Brian Rupnow (Apr 21, 2020)

It's still to cold to go and play Mr. Welder in my main garage (In fact it's snowing hard as I post this). So----Today, just to escape the "Old man stuck in the house syndrome", I found a piece of 304 stainless close to the size I wanted and made the take off pulley for Thumper. The 3 grooves are sized to tale 0.100" cross section O-rings, and all three are knurled in the bottom of the grooves to prevent slippage.


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## Brian Rupnow (Apr 21, 2020)

Petertha--I know about the acetone. I don't know if it was an absolute necessity for tig weld prep, or not. I will google a bit and try to find out.  Acetone is very smelly, and I think it's quite explosive, so I would rather not need it.


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## petertha (Apr 21, 2020)

Acetone has a distinct odor but personally I find it slightly less offensive than varsol.
I just googled auto-ignition temperatures. Acetone = 465C, Varsol = 260C. That makes acetone safer from that perspective doesn't it?

Well, some info but lots of danger precautions. I suspect be careful with any solvents in the shop especially around welding equipment, hot metals, sparks.








						Acetone Use for Welding Surface Preparation
					

Acetone is a common industrial solvent used to clean metal surfaces prior to welding. Unfortunately, when acetone fires and explosions occur in the workplace, the consequences are usually devastating. Serious injuries, burns, toxic smoke inhalation and even death are the common outcomes.




					envirofluid.com


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## Brian Rupnow (Apr 21, 2020)

Acetone cannot be used without risk of fire or explosion in any workplace which has sources of ignition. Despite the chemical’s widespread application as a surface preparation solvent prior to welding, it remains a serious hazard for workers. Acetone’s flammable and explosive properties are very difficult to adequately and consistently control.

The prevalence of the chemical in welding workshops can create familiarity and a false perception of safety. Fires and explosions from acetone will happen because of the chemical’s extreme flammability and ready evaporation. And when these accidents occur they can be deadly. The only way to fully protect workers from acetone fire and explosion risk is to use a suitable non-flammable and low evaporation chemical substitute for surface preparation.


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## Peter Twissell (Apr 22, 2020)

I like the 'grooves knurled in the bottom to avoid slippage'. I'll use that one next time my grooving tool chatters!


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## L98fiero (Apr 22, 2020)

Brian Rupnow said:


> Acetone cannot be used without risk of fire or explosion in any workplace which has sources of ignition. Despite the chemical’s widespread application as a surface preparation solvent prior to welding, it remains a serious hazard for workers. Acetone’s flammable and explosive properties are very difficult to adequately and consistently control.



I'm sure there are others but Walter has a product that will do what you need, it's promoted as a replacement for acetone. According to their Canadian site, 500 ml spray bottle is $19.20. SURFOX™ Pre-Weld – Walter Surface Technologies No connection to them, I just knew there was such a product. Personally I use acetone, I don't have the container where I'm welding, don't keep large containers of it, store it in a metal cabinet when not in use and I can get it at the hardware store a block away from home.


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## awake (Apr 22, 2020)

Whatever else you may use, do NOT use brake cleaner for weld prep. As I understand it, it can break down into toxic components under the arc.


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## L98fiero (Apr 22, 2020)

awake said:


> Whatever else you may use, do NOT use brake cleaner for weld prep. As I understand it, it can break down into toxic components under the arc.


One of the chemicals in most brake cleaners is tetrachloroethylene/perchloroethylene and with temperatures above 500 °F (260 °C) or strong UV light it decompose into phosgene and hydrogen chloride, both are toxic.  Phosgene can be lethal with as little as 4 ppm, there are stories that say people died or were seriously injured even by smoking while using brake cleaner. They are stories so take that for what it's worth, on the other hand, once exposed, there is no antidote for phosgene poisoning and even if you recover you may end up with chronic emphysema and bronchitis.


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## NickP (Apr 22, 2020)

Brian Rupnow said:


> It's still to cold to go and play Mr. Welder in my main garage (In fact it's snowing hard as I post this). So----Today, just to escape the "Old man stuck in the house syndrome", I found a piece of 304 stainless close to the size I wanted and made the take off pulley for Thumper. The 3 grooves are sized to tale 0.100" cross section O-rings, and all three are knurled in the bottom of the grooves to prevent slippage.


Hi Brian, newbie here. Please can you share how you knurled the bottom of the pulley you machined in post 244. It’s quite a narrow groove and the only types of knurling wheels I’ve seen are much wider. My knurling tool is the clamp or scissor type but I guess you could push a ‘bump’ knurler into the groove if you have a suitable wheel? If the later did you make or buy the wheel? Love the idea but have few ideas on how you go about it or the actual equipment needed. So much to learn - hope you don’t mind me asking. 
Thanks in advance, Nick


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## ALEX1952 (Apr 22, 2020)

When I was in the company fire brigade we had a beutifull Austin Gypsy fire engine complete with very pretty brass pump action fire extinguishers complete with carbon tetra-chloride filling, which was all well and good until it was laid on a storage heater and leaked, fortunately it was spotted and nobody came to harm. I'm ,told that they were developed for electrical fires in aircraft which was fine untill they realised they were losing aircraft due to the crew being overcome not air frame damage, how true I dont know but it seems entirely possible


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## a41capt (Apr 22, 2020)

petertha said:


> Acetone has a distinct odor but personally I find it slightly less offensive than varsol.
> I just googled auto-ignition temperatures. Acetone = 465C, Varsol = 260C. That makes acetone safer from that perspective doesn't it?
> 
> Well, some info but lots of danger precautions. I suspect be careful with any solvents in the shop especially around welding equipment, hot metals, sparks.
> ...


Auto ignition is the point where a flammable liquid or solid will spontaneously ignite.  ALL flammable and combustible liquids are dangerous if their properties are misunderstood. Flash point is the critical number in that it determines the temperature where the flammable/combustible liquid produces vapors at a percentage where they become flammable if an ignition source is present.

Flammable liquids have a flash point below100 degrees F, and combustible liquids are above 100 degrees F.  Many of the safety degreasers have flash points well above 130 degrees which makes them “safety” cleaners.  The interesting point chemistry wise is that generally the higher a product’s flash point, the lower its auto ignition temperature and the higher its BTU production when burning.  Gasoline (flash point -60 F) versus diesel (flash point +140 F) makes the point more easily understood, and proves the efficiency of diesel fuel.

and that my brothers, ends today’s chemistry lesson from the old retired Hazardous Materials Technician! 

John W

P.S. Acetone is the generally recommended cleaner for surfaces to be welded, especially wit TIG. Grease and oil are big enemies of clean welds.


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## awake (Apr 22, 2020)

L98fiero said:


> One of the chemicals in most brake cleaners is tetrachloroethylene/perchloroethylene and with temperatures above 500 °F (260 °C) or strong UV light it decompose into phosgene and hydrogen chloride, both are toxic.  Phosgene can be lethal with as little as 4 ppm, there are stories that say people died or were seriously injured even by smoking while using brake cleaner. They are stories so take that for what it's worth, on the other hand, once exposed, there is no antidote for phosgene poisoning and even if you recover you may end up with chronic emphysema and bronchitis.



When I first learned to weld, this was the sort of thing that made me wonder if I really wanted to learn it - though in my case, it was reading about how dangerous it was to weld anything with cadmium in it (or on it, e.g., cadmium plating).

Over time, the hyper-anxiety subsides, which is probably good up to a point ... and bad as well. From time to time I run across a thread on some horrific lathe or mill or other accident, and though it makes my toes curl, I always force myself to read it, as a way of reminding me to practice good safety.


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## Brian Rupnow (Apr 22, 2020)

Nick P--It's a neat trick.  A hundred people have asked me how I do that. I had a piece of 1" diameter 01 oil hardening steel.  I chucked it up in my lathe and  drilled and reamed a 1/4"center hole in it. Then I used  my cheap old squeeze type Chinese knurls to knurl the outer diameter x about 1/2"  long. Then I parted off a slice 0.100" thick which had the knurl on the outer diameter. Used my oxy acetylene torch to bring that slice up to cherry red, then dumped it into a tin can of old motor oil. This hardened the round slice harder than the devils horn. Then I put a .125" slot in the end of a piece of 1/2" square mild steel, with a hole thru at 90 degrees for a 1/4" mild steel axle. Loctited the axle in place, the hardened slice of knurled material is free to rotate. After the slot in the pulley I'm making has been cut with a parting off tool, I mount my  newly made skinny knurler into a tool holder for my quick change toolpost and use the topslide to bring it in against the bottom of the pulley slot, with the lathe turning at about 150 rpm. a little bit of pressure, and there you are.


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## a41capt (Apr 22, 2020)

Brian Rupnow said:


> Nick P--It's a neat trick.  A hundred people have asked me how I do that. I had a piece of 1" diameter 01 oil hardening steel.  I chucked it up in my lathe and  drilled and reamed a 1/4"center hole in it. Then I used  my cheap old squeeze type Chinese knurls to knurl the outer diameter x about 1/2"  long. Then I parted off a slice 0.100" thick which had the knurl on the outer diameter. Used my oxy acetylene torch to bring that slice up to cherry red, then dumped it into a tin can of old motor oil. This hardened the round slice harder than the devils horn. Then I put a .125" slot in the end of a piece of 1/2" square mild steel, with a hole thru at 90 degrees for a 1/4" mild steel axle. Loctited the axle in place, the hardened slice of knurled material is free to rotate. After the slot in the pulley I'm making has been cut with a parting off tool, I mount my  newly made skinny knurler into a tool holder for my quick change toolpost and use the topslide to bring it in against the bottom of the pulley slot, with the lathe turning at about 150 rpm. a little bit of pressure, and there you are.


And now I have one more piece of tooling to make!  I’ve made my own custom knurl before, but never considered one to add “traction” to slim belts. Now my Webster has something to look forward to for actual work. I’ve got an old 12 volt motor from a drill, and with a little extra electronics work, I’ll be able to charge my cell phone!!!

Thanks for the tip Brian!

John W


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## a41capt (Apr 22, 2020)

awake said:


> When I first learned to weld, this was the sort of thing that made me wonder if I really wanted to learn it - though in my case, it was reading about how dangerous it was to weld anything with cadmium in it (or on it, e.g., cadmium plating).
> 
> Over time, the hyper-anxiety subsides, which is probably good up to a point ... and bad as well. From time to time I run across a thread on some horrific lathe or mill or other accident, and though it makes my toes curl, I always force myself to read it, as a way of reminding me to practice good safety.


Andy, I started my welding career(?) in the Navy, and welding on galvanized steel was just one of the hazards associated with non-OSHA regulated working conditions. You have never been as sick as you get from Zinc poisoning caused by welding in non-ventilated spaces!  I shudder to think what else is circulating in my blood, even 50 years later...

John W


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## awake (Apr 22, 2020)

I've worried about zinc as well, having done some welding on galvanized parts - but fortunately I've never had enough exposure to have a reaction. As I understand it, that one isn't lethal unless it gets to really high concentrations ... ?


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## Brian Rupnow (Apr 22, 2020)

I have suffered from "Zinc chills" brought on by stick welding galvanized stuff. Not fun, and kind of scary, but it didn't last very long.


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## NickP (Apr 22, 2020)

Brian Rupnow said:


> Nick P--It's a neat trick.  A hundred people have asked me how I do that. I had a piece of 1" diameter 01 oil hardening steel.  I chucked it up in my lathe and  drilled and reamed a 1/4"center hole in it. Then I used  my cheap old squeeze type Chinese knurls to knurl the outer diameter x about 1/2"  long. Then I parted off a slice 0.100" thick which had the knurl on the outer diameter. Used my oxy acetylene torch to bring that slice up to cherry red, then dumped it into a tin can of old motor oil. This hardened the round slice harder than the devils horn. Then I put a .125" slot in the end of a piece of 1/2" square mild steel, with a hole thru at 90 degrees for a 1/4" mild steel axle. Loctited the axle in place, the hardened slice of knurled material is free to rotate. After the slot in the pulley I'm making has been cut with a parting off tool, I mount my  newly made skinny knurler into a tool holder for my quick change toolpost and use the topslide to bring it in against the bottom of the pulley slot, with the lathe turning at about 150 rpm. a little bit of pressure, and there you are.


Thank you Brian. A really helpful and clear answer - I really appreciate it and the tool looks great. Like a41capt (John W) said - ‘and now I have one more piece of tooling to make’ 
Great thread by the way - I’m really enjoying catching up on the engine build. Such a great resource thanks to you and everyone who contributes and takes time out of their day to answer queries and share their knowledge. 
Thanks again, Nick


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## teeleevs (Apr 22, 2020)

Brian Rupnow said:


> I wanted to buy a spray can of John Deere green today for the flywheels, gas tank, and rocker support, but the hardware store is closed because of Covid. I wanted to practice some more tig welding today, with special attention given to the foot-pedal, but it was too cold in my main garage. I wanted to take a longer "fat mans walk" but I've got bad arthritis in my left knee. I wanted to go see my grandkids, but I can't because wife and I are "social distancing". All in all, I haven't done a hell of a lot today except cruise the internet and read the forums.  I've had a very much "useless old man day"!!!


We are never " useless old men" just slowed down a little, and in my part of the world we are still getting days of 33 C Ted


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## fabricator (Apr 23, 2020)

Hi guys, newbie to the forum and following this build. I'm retired from 32 years as a sheet metal fabricator and just throwing this out there. Acetone has been commonly used as an aluminum welding pre-clean for many years and is used every day. I'll also say that chemical pre-clean is only the last step. Mechanical cleaning is the most important step, chemicals can never remove what a stainless wire brush can. If you want an aluminum weld to be proud of you need to get the spot to be welded down to as close to virgin metal as possible. Also on the tig welder pedal thing, as a general rule, it's all about practice and muscle memory. For the most part, if you can drive a vehicle and operate the steering wheel and the brake pedal and look out the windshield at the same time you can get used to using a tig pedal.


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## Brian Rupnow (Apr 23, 2020)

Yesterday I bought two new stainless steel brushes. I have trouble chewing gum and walking at the same time, but I'm sure practice with the tig pedal will give me a much better result with my welding. It is still unusually cold here, and my main garage is unheated. I hope to get out into my main garage for more practice sessions with the tig welder later this week.


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## fabricator (Apr 23, 2020)

Brian Rupnow said:


> Yesterday I bought two new stainless steel brushes. I have trouble chewing gum and walking at the same time, but I'm sure practice with the tig pedal will give me a much better result with my welding. It is still unusually cold here, and my main garage is unheated. I hope to get out into my main garage for more practice sessions with the tig welder later this week.



Ha ha, I hear the walk and chew gum thing. I was the kid in school who couldn't operate a baseball glove. We had some snow flurries on the west coast of Michigan yesterday but it's supposed to get hot today, 54 F.


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## awake (Apr 23, 2020)

fabricator said:


> ... if you can drive a vehicle and operate the steering wheel and the brake pedal and look out the windshield at the same time ...



Wait - you're supposed to do all of that at the same time?!? Maybe that explains all these tickets I got ...


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## fabricator (Apr 23, 2020)

awake said:


> Wait - you're supposed to do all of that at the same time?!? Maybe that explains all these tickets I got ...


Well, yeah in between texting and watching youtube.


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## awake (Apr 23, 2020)

YouTube! That's what I've been missing as I drive. Gotta add that one in. Hmm ... do you think the police would object if I set up a projector to put YouTube as a HUD on the windshield?


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## fabricator (Apr 23, 2020)

awake said:


> YouTube! That's what I've been missing as I drive. Gotta add that one in. Hmm ... do you think the police would object if I set up a projector to put YouTube as a HUD on the windshield?


What could possibly go wrong?


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## Brian Rupnow (Apr 24, 2020)

No machining, no tig practice!! I'm sick. Not the killer virus, just a nasty flu bug---more in my guts and body aches than anything. No temperature and no congestion. I needed something to do, so today I came down to my office and filled in the "custom properties" for all the components on Thumper.  Filling in the "custom properties" of each component lets the description of that part appear in the main bill of materials, both on the main assembly drawing, and also on any sub assembly and part drawings.  This is not something I would normally do on model engine drawings, but boredom makes me do strange things. I bought a spray can of John Deere Green paint for my flywheels, but after my wife went to the trouble of picking it up for me, I decided I didn't like the color. I've arranged to pick up a spray can of darker green tomorrow.


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## fabricator (Apr 24, 2020)

Take a few days off and take care of yourself man we can wait.


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## Brian Rupnow (Apr 25, 2020)

Still feeling crappy, but good enough to go for my "fat mans walk" and watch YouTube videos. There is a 4 part series of videos about "This Old Tony" making a go cart for his son. There is nothing too amazing about the go cart, but my God, the man is a virtuoso with a tig torch. He makes it look so easy to weld up all the different joints. I've built a couple of go carts over my lifetime, but the frames were either stick welded together out of old bed frame angles or oxy-acetylene brazed from electricians conduit.


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## fabricator (Apr 25, 2020)

TOT is one of my favorite channels, he has a lot of good content and is also very entertaining. Especially when he does his magic material chopping.


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## wthomas (Apr 26, 2020)

Hi Brian:
    I agree with fabricator, I sure do enjoy Tony.  On tig welding you will be surprised how good and what you can do with tig
as you continue to use it.  I was working on a test stand attached to a lab oven and had to weld about a 2 1/4" square box with
a 2" round tube in the bottom in the lower side of the oven.  The round tube cam half way through the wall of the oven and I was
installing the box to the tube.  The box was being added to fit the test stand I had designed and built.  I found a flex head torch
that I could flex inside the box and weld the tube to the bottom of the box.  The box was about twice the thickness of the thin tube
so by aiming the heat into the box from the opposite side of the tube I was able to feed the rod straight into the joint while standing
bent over almost onto head.  (No room to lay down or get in a good welding position.)
                                                           NOW still stuck in the house till May 15, 2020  (NOTE:  over a 100 people died in one day in the next county)
                                                                            Bill Thomas                
                                                                                       Michigan usa


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## erdelskyjj (Apr 26, 2020)

I follow several forums and this build came up on my radar.  Reading through from the first to the the last I must commend you for a a very educational sequence of design and build.  One statement in post #116 was reference to cam cutting in a video by Chuck Fellows and an old thread of yours on his method.  I looked for Mr Fellows and found that he has passed, and no references to his videos came up.  Can you direct me to his video and your past thread on the subject?  I will continue to follow to the first put-put.


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## Brian Rupnow (Apr 26, 2020)

This link gets you to the Chuck Fellows video




__





						Video Search Results
					

The search engine that helps you find exactly what you're looking for. Find the most relevant information, video, images, and answers from all across the Web.




					ca.video.search.yahoo.com
				



And this video will get you to a thread I created on one of the forums, using the Chuck Fellows method.





						Quick way to cut a cam
					

I first seen this method of cutting a cam on a YouTube clip posted by Chuck Fellows. In his video, he attributes this method to Randall Cox. I have made cams using various methods, and this is by far the fastest method if you want a cam with a "flank radius" between the base circle and the nose...




					www.homemodelenginemachinist.com


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## Brian Rupnow (Apr 27, 2020)

And here we have the second flywheel/fan hot off the welders bench. Ignore the stuff to the left of the flywheel---thats just practice welding.  I spent an hour this morning playing with the foot-pedal while welding, to get used to changing the size of the arc puddle and not letting everything run away out of control. The flywheel still has to be cleaned up, and "trued" on the lathe but it looks a lot better than the first flywheel did immediately after welding. I am an old dog, but I am learning new tricks.


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## fabricator (Apr 27, 2020)

That's not bad at all for somebody that has only tig welded a couple of times.


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## dsage (Apr 27, 2020)

SO what did you find with your pedal experiments. Were you able to "throttle back" to the point where nothing was melting and you just have the tiniest of arcs?


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## Brian Rupnow (Apr 27, 2020)

dsage---Yes--I did exactly that. things went much better.---
Leapin' Lizards Annie--Just look at that thing!!! Both flywheels fit where I intended them to. I could probably spend a day "fettling" around the welds to blend everything in, but I'm not going to. Plan is to knock down any high spots and any sharp points, then paint them. I had purchased a can of John Deere Green, but decided that I didn't like it. Went back and bought a darker green which I think will look nice.


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## fabricator (Apr 27, 2020)

More weld left means stronger joints. You are going want to keep an eye on those welds though. There will be some flexing because of the inertia of the outer ring and it doesn't take much to start cracking a weld.


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## Peter Twissell (Apr 27, 2020)

Looks very purposeful Brian. I look forward to video of it running as slow as I imagine it will.


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## wthomas (Apr 27, 2020)

Hi Brian:
    I bet that old dog is really wagging it's tail!  Ha ! Ha !   Good job!
   I  was able to get out of the house yesterday but went NOWEAR!!
                                                  Bill Thomas
                                                       stuck inside in Michigan USA


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## Brian Rupnow (Apr 27, 2020)

wthomas--You made me laugh. In times like this anything that makes me laugh is very welcome!! This afternoon I finished the cleanup of the flywheel I welded this morning, then disassembled the engine for paint, and painted the flywheels, gas tank, and rocker arm support a nice green color.  I get out every day around 2:00 o'clock to go for my "fat mans walk" on the forest trails across the road from my house. It's only a mile in total, but most of it is hilly.


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## Brian Rupnow (Apr 28, 2020)

Ladies and Gentlemen-I present "THUMPER" in all it's beauty. Yesterdays paint job dried overnight, and everything got unmasked and assembled this morning. Now I get to the point where "Thumper" can not stay on it's merits as being pretty---It has to actually run for me. I started this build on or about the 1st. of March, and had everything completed by the beginning of April except for the flywheel/fan blades. I had some time in April devoted to purchasing and learning to use a new Tig welder, and a few days of stomach flue. I am happy with the way this engine turned out, and will be even happier if the next stage (getting it to run) goes fairly easy on me.----Brian


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## werowance (Apr 28, 2020)

very nice.


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## CFLBob (Apr 28, 2020)

Looking excellent, Brian.


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## a41capt (Apr 28, 2020)

Looks great Brian!


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## Smokey Joe (Apr 28, 2020)

I like it Brian.. I can almost hear it thumping already.
Joe


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## Brian Rupnow (Apr 28, 2020)

Now we get to talk about cam timing. As you can see in the drawing, there is about 125 degrees of "cam influence". That gets doubled when you think of what is happening at the crankshaft, because of the 1:2 ratio between the crankshaft gear and the camshaft gear. So---at the crankshaft we have 250 degrees which we have to account for. When the piston travels full stroke from top dead center to bottom dead center, that accounts for 180 degrees. so 250-180=70 degrees. I like to have the intake valve start to open about 20 degrees before the piston reaches top dead center on the exhaust stroke. I can adjust the cam position to make this happen. If we take that 70 degree figure and subtract the 20 degrees from it, then that means that the intake valve will close 50 degrees into the compression stroke.--I can't set that last figure. That last figure is totally dependent on the shape of the cam. I like my exhaust valve to begin opening at 45 degrees before bottom dead center on the power stroke, and I can set that. So, again, if you subtract that 45 degrees from 70 degrees, that means that the exhaust valve stays open until 25 degrees into the intake stroke.  I will set the cams up as written in the text, and see what happens. These calculations do not take valve lash into account, but they seem to work for me when the valve lash is set to about 0.010".


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## awake (Apr 28, 2020)

Looks great! Ready to hear it thump.


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## dsage (Apr 29, 2020)

A very hansom engine. Looks like it means business.  
As for cam timing you can always leave a bit more lash if you're not happy with the open and close positions.


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## payner (Apr 29, 2020)

Good looking engine as usual . I will be interested in seeing a video of it running .


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## propclock (Apr 29, 2020)

Enjoyed your build very much.  Especially the TIG experience. I never learned to weld.
So I always find a way around it. But I know it is a powerful tool, perhaps one day. 
Your engine reminds me of the OLD mac truck Dog figure, Squat and powerful. 
Thanks for sharing, Thanks for taking the time to share.


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## Brian Rupnow (Apr 29, 2020)

This morning I'm setting valve timing. There is a lot going on in this picture. On the far side of the engine is a cardboard protractor I made up. It has a wood base and a clearance hole thru it for the crankshaft. It has the degree marks that I want to set my valves to printed on it---20 degrees before top dead center and 45 degrees after bottom dead center. There is a temporary metal stand made up for my dial indicator, and the end of the indicator is setting on top of the intake valve rocker arm. I think I have a Canadian two dollar coin in there for a spacer because I couldn't get the dial indicator quite low enough without modifying the temporary stand. For the intake I have found and marked the flywheel at top dead center, then turned the crankshaft backwards until the top dead center mark on the flywheel was lined up with the 20 degree before top dead center mark on the protractor.(grub screws in intake cam and both gears are locked to camshaft and crankshaft.  Then I loosen off the grub screws in the crankshaft gear and turn the camshaft gear in the correct direction until I see the dial indicator start to move. I then lock the crankshaft gear grub screws and the intake valve is set. The exhaust valve is more difficult, because the cam and crank gears are locked in position. I set the crankshaft in a position that is 45 degrees before the piston reaches bottom dead center. I loosen of the grub screws in the exhaust cam and set the dial indicator up on the exhaust valve. Then without moving crankshaft or camshaft, I have to reach in thru the "window" and spin the exhaust cam in the correct direction until it contacts the lifter. (This is far easier said than done). then the grubscrews in the exhaust cam are locked up.


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## minh-thanh (Apr 29, 2020)

Looks great !!  .  wait to seeing a video of it running


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## Brian Rupnow (Apr 29, 2020)

I thought I had mentioned this in my previous post, but I see that I didn't. What I did this morning does not take into account any valve lash. I set my valve lash for 0.010" after the cams are located and locked in place. In reality, the valve lash means that the cam has to turn a very little bit more than perfect design parameters before the valve starts to lift.


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## Brian Rupnow (Apr 29, 2020)

*YES!!!*--The engine runs. It had fairly weak compression to begin with, gave a lot of pops and farts, but didn't want to run on it's own. I advanced the timing about 10 degrees, but no joy. Everything was set to "optimum" but it didn't want to keep running on it's own. I have a new (used)1/4 horsepower electric motor that I bought a couple of months ago. I set it up and ran a v-belt from one of the motor pulleys to the offside flywheel, turned on the switch and let the electric motor run the engine.  The engine was firing right along with the motor running it. The cylinder got warm and the exhaust was warm, so I just let it run. I knew that with combustion happening, the valves would begin to seal better and the rings would seat. After about 15 minutes I stopped everything, took the belt off, and started the engine the normal way, with my electric drill. I am very pleased, the engine is a runner. Now it's just a matter of taming it a bit to get a good idle and throttle response. Now that I know the engine runs okay, I will sell the plans for $25 Canadian---contact me by email. I haven't been able to get Youtube to work for me for the last month or so, but tomorrow I will get a video of it with my camera and see if my wife can open a new account on Youtube. If she can't I'm going to have to figure out another way of getting a video to post.---Brian


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## a41capt (Apr 30, 2020)

Hurray!  This is a unique engine, and I look forward to seeing all that crankshaft action in motion!

Congratulations Brian, and I’m keeping my fingers crossed that you’ll solve your YouTube problems.

John


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## Brian Rupnow (Apr 30, 2020)

If I have one complaint about Traxxas 4033 carburetors, it's this. If you don't have some over-riding control on the throttle, then as soon as your engine starts it will open the throttle wide open. The only way I have found to get around that is to make up my own throttle lever with a good heavy compression spring at the pivot point and a lever connecting it to the Traxxas throttle lever. That way the engine stays at whatever throttle setting you choose. It is very exciting to have your brand new engine start and immediately rev up to the point where you are afraid it may explode before you get the ignition switch shut off.


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## CFLBob (Apr 30, 2020)

Brian Rupnow said:


> .......If you don't have some over-riding control on the throttle, then as soon as your engine starts it will open the throttle wide open. The only way I have found to get around that is to make up my own throttle lever with a good heavy compression spring at the pivot point and a lever connecting it to the Traxxas throttle lever.



Is that the brass rod at the top right?  If not, could you highlight it or do a picture of it?  

If it's what I think, it looks a bit complicated - 3 or 4 parts.


Thanks!


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## Brian Rupnow (Apr 30, 2020)

Close Bob---it's two parts. The brass is attached to the aluminum with j.b.weld.


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## Brian Rupnow (Apr 30, 2020)

Quick question--What degree of ignition advance do you guys use on single cylinder four cycle engines? I have always set my ignitions up for 10 degrees advance. I am into fine tuning on this engine, and I'm curious. I tried to google it and got 4 billion answers and non of them really answered what I was trying to ask.


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## a41capt (Apr 30, 2020)

Sorry I can’t help Brian, but my only experience is with my Ford Kitchen Sink engine, and that thing is unlike ANY other engine I’ve ever been exposed to. As I’m building a Webster right now, I’ll be watching for replies so I can sort out my own timing issues as they arise.

John


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## minh-thanh (Apr 30, 2020)

Brian Rupnow said:


> Quick question--What degree of ignition advance do you guys use on single cylinder four cycle engines? I have always set my ignitions up for 10 degrees advance. I am into fine tuning on this engine, and I'm curious. I tried to google it and got 4 billion answers and non of them really answered what I was trying to ask.


Brian !
I usually set 15 degrees before TDC


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## wthomas (May 1, 2020)

Hi Brian:
    I bet the old dog's tail was tucked between his legs when that throttle
shifted wide open!!  Ha! Ha!  It must have really sounded out 
as it rev'ed up.
                          I got out Wed. of this week!!!!
                                Bill Thomas             
                                     In Michigan  USA Where people are dieing by the 100 every day!!


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## Peter Twissell (May 1, 2020)

For a fixed ignition timing, the advance is a compromise between two factors:
1) The speed and load at which you want best performance. Ignition is advanced so that flame can propogate through the charge and combustion can proceed to a peak pressure just as the piston reaches TDC. At low throttle settings, the charge density is low and flame speed is also low, so more advance is required.
2) Starting - not so much of an issue if you're spinning the engine over with a power drill etc, but if you're hand cranking it can be a serious problem. My Panther motorcycle is quite capable of launching me over the bars if I tried to kick it over with ignition advanced.

So, I'd guess you are looking for a smooth engine at low RPM.
Best appraoch is probably to adjust timing with the engine running until you're happy.


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## a41capt (May 1, 2020)

Peter Twissell said:


> My Panther motorcycle is quite capable of launching me over the bars if I tried to kick it over with ignition advanced.



Wow, Phelon and Moore? I’m MORE than suitably impressed!!!!

John W


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## Brian Rupnow (May 1, 2020)

Okay---I've conducted a poll. Art says 14 degrees. I thought it was 10 degrees. Three small engine shops I called answered 28 to 30 degrees, one guy was very certain that on single cylinder engines with no mechanical advance it was 23 degrees, and a third shop owner said he always set for 25 degrees before top dead center. Unless somebody can offer me up a better solution, i'm going to set my ignition timing up to fire 15 degrees before top dead center.


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## awake (May 1, 2020)

Brian, I wonder if some of the diversity of opinion has to do with whether the measurement is on the cam or on the crank - it occurs to me that all of the answers above could be close to the same, if the 10, 14, 15 degrees are on the cam and the 25, 28, 30 degrees are on the crank.

I have played with the ignition timing on my Webster, from way advanced to slightly retarded, and I can't tell much difference - which makes me wonder what I'm doing wrong ... !


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## Brian Rupnow (May 1, 2020)

Measurements are always taken on the crankshaft. For instance, ignition set to fire at 15 degrees before top dead center is talking about the crankshaft rotating and moving the piston towards top dead center. At 15 degrees before the piston reaches top dead center, the spark occurs. And you're right---it's a wide open target. I have always set up my engines to fire "Just before top dead center". I'm trying to be a bit more scientific about it this time. Incidentally, when the crankshaft goes from 15 degrees before top dead center up to top dead center, it only moves the piston 0.027" vertically.


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## TonyM (May 1, 2020)

The old school method on a full size car engine was advance it till you get pre-ignition / knocking then retard until it stops knocking and that was about right. I don't think it helps with model engines as we can't generally adjust ignition timing with the engine  running.


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## awake (May 1, 2020)

I did set the Webster up to allow adjustment while running, but that's where I wasn't able to detect any difference, moving through the entire range of adjustment that I have, which is roughly 50° advance through 20° retard. Mind you, I've never adjusted timing on a car other than years ago with a timing light, so I'm not sure what to listen for. And of course, when I tried this I was still trying out different needle and throttle settings. All of which is to say, I have very little idea of what I'm doing!


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## Brian Rupnow (May 1, 2020)

It's not often that I learn something new which impresses me, but it does happen. I have always set my engines ignition timing by ear and "about 10 degrees advance". This morning I was calling around to small engine repair shops to get a concensus on this timing. I never did get a clearly cut concensus on this, but ended up taking 15 degrees before top dead center as the best time for spark. However, I heard the following method of setting ignition advance, and it just blew me away. The first step is to use either cad or trigonometry to see how far up the piston moves between top dead center and 15 degrees before top dead center. In my case, with a crank throw of 0.687", the piston moves up 0.027". Pull the cylinder head off, and with the piston at top dead center, measure from the top of the cylinder down to the top of the piston. In my case that was 0.106". add the 0.027" to that, and you get 0.133". Make a disc that thickness, slightly smaller than the piston diameter. Set it on top of the piston, then bolt a bar across the top of the cylinder and then turn the crankshaft in the correct direction until the piston presses the disc against the underside of the bar. that is exactly where you want the spark to occur.


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## Brian Rupnow (May 1, 2020)

Remove the flywheel on the side where the ignition points are, set the ignition points for a 0.020" gap, then loosen off the grub screws in the ignition cam. Hook up the battery and sparkplug and while still holding the piston tight against the underside of the bar, rotate the cam in the right direction until you get a good fat spark. Lock the cam grubscrews there, and the engine will be timed to exactly 15 degrees before top dead center. Remove the retaining bar and the disc and bolt the cylinder head and flywheel back in place.


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## fabricator (May 1, 2020)

That seems like a foolproof way to get the desired number perfectly with zero seat of the pants (guess work} involved. I'm going to save that one.


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## teeleevs (May 1, 2020)

Wow, great excitement, good for the pacemaker.


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## minh-thanh (May 1, 2020)

*Hi Brian !*
Just one more discussion:
when I changed the fuel for the engine: gasoline (mixed w40) and nitro fuel (including 2-stroke and 4-stroke engines)
With gasoline ( mixed w40): I set the ignition to 15 degrees before TDC
Nitro fuel: I set the ignition less a few degrees , somewhere around 12 degrees
I don't know why, maybe I didn't set it right, or because the fuel was easier to burn, or because  nitro fuel  had more oil, so the compression increased, or ...something
So, for every fuel I use, I usually choose 15 degrees before TDC, and then adjust the ignition a little bit - until I feel the engine runs best and stop ,.


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## wthomas (May 2, 2020)

Andy (awake)
     Would you mind telling us what kind of carburetor and the engine you were setting the timing on?
Also, about how slow of RPM was you able to get it to Idle?
        Thanks in advance for the information as it will answer my thoughts on how slow can you Idle an 
engine.
                       Bill Thomas
                                  Still locked down in Michigan USA


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## dsage (May 2, 2020)

There is no magic wand on where to set the timing. Advance is totally dependent on the engine you're setting it on and the conditions it is running in. That's why it's one of those things that even the simplest engines that have a variable load have to manage. i.e. vacuum advance - centrifugal advance in order to get peak performance.
If you're going to just sit it on the bench and run it at a certain rpm then set it anywhere reasonable that it's happy. It won't care.
Your process is perfect to get it set exactly for what ever you've decided to set it at.
But I assumed all along that you were going to un-leash this beast on "the saw" 

Do yourself a favour and enlist some of your wonderful design talents and make it at least manually adjustable. Or if you want to get fancy have the advance increase with throttle position (to a ratio). (a simple linkage)
In most cases a simple lever adjustment is just a matter of turning the plate the points are mounted on.
Once you have it adjustable you can set it depending on the running conditions (half the consensus reached here). You can retard it slightly for starting and in general the engine will run smoother and have more power if you advance it with rpm. If you're going to load it i.e.  "the saw"  then it will be  necessary to be able to adjust it for best performance (ability to carry the load). You'll find a marked improvement in it abilities.

Looks really good.

Of course - all this coming from a guy who can't even get the Atkinson to pop


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## Brian Rupnow (May 2, 2020)

dsage-I agree with everything you have said.---But---Right now I'm dealing in "absolutes". The engine is finished, and I have had it running. Not great, not slowly, but running on it's own for protracted periods of time. The timing was set to "By guess or by God". Now I have brought the engine back into my workshop, and set the timing "scientifically". As soon as I get it to run smoothly, I will put up a video (somehow) and then if I want to mess around with timing I will design in a timing plate that lets me play with the timing while the engine is running.---Brian


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## Brian Rupnow (May 2, 2020)

I must have done something right. I finished my fine tuning on Thumper, and was able to upload a video of it running. Youtube seems to be working okay for me now. There may be more videos of Thumper driving one of my mechanisms, but for now here is a video of Thumper by itself. thank you to all who have followed this build.---Brian


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## CFLBob (May 2, 2020)

Congratulations, Brian!  Nice looking little engine.


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## dsage (May 2, 2020)

Very nice Brian. Congratulations. I don't hear any missing or mis-behaviour. It runs very smooth and about the right speed I'd say.
Not much more to do really.

Thanks for keeping us all tuned in.


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## awake (May 2, 2020)

Brian, that sounds great! I look forward to more videos.


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## awake (May 2, 2020)

wthomas said:


> Andy (awake)
> Would you mind telling us what kind of carburetor and the engine you were setting the timing on?
> Also, about how slow of RPM was you able to get it to Idle?



Bill, this was my "Steel Webster" on which I am slowly catching up the build log here on the forum - but I haven't gotten to the carburetor yet on the log. It is a slightly modified "Chuck Fellows" carburetor - pretty simple, but also seems to work quite reliably, at least in that an absolute newbie (me) got the engine running with it shortly after getting everything assembled. Since then I have come to the conclusion that I was at least a bit lucky - my needle and throttle settings were close enough to let it start by hand, as I had not yet made an adapter to allow starting with a drill.

In terms of RPM, the slowest I've had the Webster running is around 900 rpm, but it is much happier at 1000. Top speed that I've run it is around 3000, but I have not tried to run  it very long at that speed - worried about bits flying off!


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## a41capt (May 2, 2020)

That’s another great running engine Brian, congratulations!

John


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## fabricator (May 2, 2020)

Brian, have you checked your messages lately? I'd like to order plans for Thumper.


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## Brian Rupnow (May 2, 2020)

I have a number of requests for plan sets. Tomorrow I will open each drawing and save it as a pdf file so that no special software is needed to open and print the drawings. This will take a couple of hours, as there are 60 drawings and some of them are multiple sheets. I charge $25 Canadian funds, payable to Paypal. If you send money to [email protected] at Paypal, they will notify me and I will send you a zip file with all of the part and assembly drawings. Please specify that it is the drawing set for "Thumper".---Brian Rupnow


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## fabricator (May 2, 2020)

Brian Rupnow said:


> I have a number of requests for plan sets. Tomorrow I will open each drawing and save it as a pdf file so that no special software is needed to open and print the drawings. This will take a couple of hours, as there are 60 drawings and some of them are multiple sheets. I charge $25 Canadian funds, payable to Paypal. If you send money to [email protected] at Paypal, they will notify me and I will send you a zip file with all of the part and assembly drawings. Please specify that it is the drawing set for "Thumper".---Brian Rupnow


Will do, no real rush.


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## teeleevs (May 2, 2020)

Brian Rupnow said:


> Okay---I've conducted a poll. Art says 14 degrees. I thought it was 10 degrees. Three small engine shops I called answered 28 to 30 degrees, one guy was very certain that on single cylinder engines with no mechanical advance it was 23 degrees, and a third shop owner said he always set for 25 degrees before top dead center. Unless somebody can offer me up a better solution, i'm going to set my ignition timing up to fire 15 degrees before top dead center.


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## teeleevs (May 2, 2020)

Brian Rupnow said:


> Okay---I've conducted a poll. Art says 14 degrees. I thought it was 10 degrees. Three small engine shops I called answered 28 to 30 degrees, one guy was very certain that on single cylinder engines with no mechanical advance it was 23 degrees, and a third shop owner said he always set for 25 degrees before top dead center. Unless somebody can offer me up a better solution, i'm going to set my ignition timing up to fire 15 degrees before top dead center.


Brian, I tried to send a short video of my model Fairbanks Morse  powered railway trolley (but was unsuccessful ) which I could easily start at 15 degrees by flicking it over with my fingers but I had to advance it much more than that to get it to run properly so then I needed to fit a rope start.  How can I email such videos? It works hard and I ride it around the model railway track.


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## Brian Rupnow (May 2, 2020)

Post the video on Youtube. Then copy the url at the top of the screen while the video is playing and send it to me.----Brian


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## johwen (May 3, 2020)

Brian Rupnow said:


> Quick question--What degree of ignition advance do you guys use on single cylinder four cycle engines? I have always set my ignitions up for 10 degrees advance. I am into fine tuning on this engine, and I'm curious. I tried to google it and got 4 billion answers and non of them really answered what I was trying to ask.


Hi Brian Here's how I do it... Set the engine speed at around 1500rpm with the timing set at TDC. Then advance the ignition timing to obtain the maximum rpm and that should be your best setting.
If you have a taco to read the rpm it is even more accurate to just stop advancing when it reaches max at that throttle setting and advance. You don't gain anything by having it too far advanced.
You want the maximum burn pressure to occur in the cylinder at say 5 degrees after TDC and at speed you need to advance the timing for the fuel burn to reach that phase. When you set the engine speed to 1500rpm adjust the mixture of the fuel to maximum rpm first then the timing. As compression and mixture  will change the burn rate and consequently the ideal timing.
Hope this helps as I'm a retire Auto engineer and spent many years engine tuning.
Johwen JohnSamphier

P.S. I just noticed you have your points at a fixed setting This makes it difficult! Have you though of mounting your points on a movable plate so you can advance and retard with the engine running. With you excellent engineering talet would not be very difficult and remove the guess work?


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## payner (May 3, 2020)

Brian . Engine looks and sounds great , can't wait to see a video of it driving a load .
Bill


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## Brian Rupnow (May 3, 2020)

Johwen--I may add an adjustable plate between the points and the engine casing. I have done that before and it worked well to set the timing while the engine is running.---Brian


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## Peter Twissell (May 3, 2020)

Congratulations on a very pretty and sweet running engine Brian.


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## Brian Rupnow (May 3, 2020)

I was asked yesterday what rpm the engine was running at in the video. I checked it this morning with the engine driving the clutch. It seems very comfortable at 975 to 1000 rpm. If I turn the idle screw to let it run slower, it stumbles and stalls.


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## teeleevs (May 3, 2020)

dsage said:


> There is no magic wand on where to set the timing. Advance is totally dependent on the engine you're setting it on and the conditions it is running in. That's why it's one of those things that even the simplest engines that have a variable load have to manage. i.e. vacuum advance - centrifugal advance in order to get peak performance.
> If you're going to just sit it on the bench and run it at a certain rpm then set it anywhere reasonable that it's happy. It won't care.
> Your process is perfect to get it set exactly for what ever you've decided to set it at.
> But I assumed all along that you were going to un-leash this beast on "the saw"
> ...


I learned to drive at 14 in a 1925 Buick, had to work on the manual spark advance all the time, every hill  you had to set it back a little, then down the other side you set it up more, woubetide if you forget to retarded it before you put that crank handle in!


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## teeleevs (May 3, 2020)

Brian Rupnow said:


> I was asked yesterday what rpm the engine was running at in the video. I checked it this morning with the engine driving the clutch. It seems very comfortable at 975 to 1000 rpm. If I turn the idle screw to let it run slower, it stumbles and stalls.


Looking good Brian


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## Brian Rupnow (May 3, 2020)

I've spent much of today "dialing and tweaking" to see how slow I could get the engine to idle. It idles at about 950 to 1000 rpm with no load at all on the engine, and idles at 800 rpm quite happily with the load of a driven clutch on it. If I try for anything lower than that, it just gives up and stalls.


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## ShopShoe (May 4, 2020)

Great to see and hear it running, Brian.

Speed seems to sound about the same as some genuine antique engines working that I have heard.

Thank You for all your posts.

--ShopShoe


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## werowance (May 4, 2020)

Brian,  that sure is a nice engine you have built.  congratulations on yet another fine runner.  curious about the air flow the fins in the fly wheels create,  alot, some or ???  you may have said something in the videos but i cant play them with sound on so i dont know.  but it seems to run slow enough for me to be able to watch the valves in action which is nice.


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## Brian Rupnow (May 4, 2020)

Werowance--they do move a lot of air. And just as I suspected, the air is drawn into the "fans" not in a direct line, but in a funnel shape. This means that there is a lot of air turbulence around the cylinder. I'm pleased with the volume of air that the "fans" move.---Brian


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## Willyb (May 4, 2020)

Hi Brian

Interested in how well your engine is balanced when running. As with allot of scale model engines they need to be bolted to a stand/base board or sometimes clamped to a table top. Have you tried running your engine unrestrained?  I am thinking that it's layout should result in a smooth runner. 

Cheers
Willy


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## Brian Rupnow (May 4, 2020)

Willy---I clamp or screw-nail all my engines down before trying to start them. I use my variable speed electric drill for a starter. If an engine floods and hydro-locks you can watch six or eight weeks of work go flying onto the cement floor and smash to pieces if the engine isn't securely held down.


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## teeleevs (May 5, 2020)

Brian Rupnow said:


> I've spent much of today "dialing and tweaking" to see how slow I could get the engine to idle. It idles at about 950 to 1000 rpm with no load at all on the engine, and idles at 800 rpm quite happily with the load of a driven clutch on it. If I try for anything lower than that, it just gives up and stalls.



Hi Brian and whoever is interested, Your engine is ticking over fine Great Job.  I have uploaded a video  to Youtube, thanks for watching, Ted


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## teeleevs (May 5, 2020)

teeleevs said:


> Hi Brian and whoever is interested, Your engine is ticking over fine Great Job.  I have uploaded a video  to Youtube, thanks for watching, Ted



So I have again unsuccessful with my post, I will try again maybe another video.


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## teeleevs (May 5, 2020)

teeleevs said:


> So I have again unsuccessful with my post, I will try again maybe another video.


Ok this is the real Inspectors Motor Trolley. No history is available except there is a brass tag attached saying it was brought down to the Ipswich Rail Museum Queensland Australia from Normanton Far North Queensland in 1973.  It is an all wood design even the wheels have wooden spokes.  A close look at the engine reveals several clues to its age, no carburettor just a hollow box, only speed control is a lever to hold the exhaust valves open, buz coil ignition, no spark plugs as we know them, no cooling fins. The engine is Fairbanks Morse and obviously runs very slow ie 100 RPM = 15 MPH the trolley uses the flywheel as the driving wheel.  This is 1880s technowledgy.  It is possible that it was used during the building of the Normanton to Croyden line 1889.   In use it was pushed along the line and when up enough speed driver had to jump aboard and release the valves.


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## teeleevs (May 5, 2020)

teeleevs said:


> Ok this is the real Inspectors Motor Trolley. No history is available except there is a brass tag attached saying it was brought down to the Ipswich Rail Museum Queensland Australia from Normanton Far North Queensland in 1973.  It is an all wood design even the wheels have wooden spokes.  A close look at the engine reveals several clues to its age, no carburettor just a hollow box, only speed control is a lever to hold the exhaust valves open, buz coil ignition, no spark plugs as we know them, no cooling fins. The engine is Fairbanks Morse and obviously runs very slow ie 100 RPM = 15 MPH the trolley uses the flywheel as the driving wheel.  This is 1880s technowledgy.  It is possible that it was used during the building of the Normanton to Croyden line 1889.   In use it was pushed along the line and when up enough speed driver had to jump aboard and release the valves.


  Hope this one works, Must apologize for the dog wanting to get in on the action.


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## awake (May 5, 2020)

Brian Rupnow said:


> Now we get to talk about cam timing. As you can see in the drawing, there is about 125 degrees of "cam influence". That gets doubled when you think of what is happening at the crankshaft, because of the 1:2 ratio between the crankshaft gear and the camshaft gear. So---at the crankshaft we have 250 degrees which we have to account for. When the piston travels full stroke from top dead center to bottom dead center, that accounts for 180 degrees. so 250-180=70 degrees. I like to have the intake valve start to open about 20 degrees before the piston reaches top dead center on the exhaust stroke. I can adjust the cam position to make this happen. If we take that 70 degree figure and subtract the 20 degrees from it, then that means that the intake valve will close 50 degrees into the compression stroke.--I can't set that last figure. That last figure is totally dependent on the shape of the cam. I like my exhaust valve to begin opening at 45 degrees before bottom dead center on the power stroke, and I can set that. So, again, if you subtract that 45 degrees from 70 degrees, that means that the exhaust valve stays open until 25 degrees into the intake stroke.  I will set the cams up as written in the text, and see what happens. These calculations do not take valve lash into account, but they seem to work for me when the valve lash is set to about 0.010".



Brian, valve timing is something that I feel like I only barely understand. Any words of wisdom to offer on how you came up with the 125° angle of action and the 20° BTDC / 45° BBDC settings at which the valves begin to act? Or any reference works that have been particularly helpful to you as you have designed your engines?


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## Brian Rupnow (May 5, 2020)

Valve timing is a black art. I have read many articles dealing with it, and I only understand about 30% of what I have read. I can't give you any particular reference texts, since I have been reading various and sundry articles about it for many years. Basically, it goes something like this. In a world of pure theory, the intake valve would spring open at exactly the beginning of the intake stroke, spring closed exactly at the bottom of the intake stroke, and the exhaust valve would spring open exactly at the beginning of the exhaust stroke and spring shut at the end of the exhaust stroke. However, in the real world, we have inertia and time to deal with. The valves don't really "spring" open or closed. They need to gradually ramp up from fully closed to fully open, and vice versa. They may even have to "dwell" in the opened or closed position for a split second. Also, considering inertia, the charge of fuel and the charge of exhaust both need a little time to start moving. To compensate for inertia, the intake valve can actually begin to open slightly before the beginning of the intake stroke, and can even remain open part way into the compression stroke. The exhaust valve can begin to open during the power stroke, remain open all the way thru the exhaust stroke, and even during the first bit of the intake stroke. The point at which the valves proceed to open and to close are determined by the profile of the cam. The profile of the cam is determined by how fast the engine is designed to run. This opening before and after the theoretical tdc and bdc are referred to as valve lead and valve lag. The faster the engine is designed to run, then the more lead and lag will be designed into the cam because everything has to happen in a much shorter period of time. I have built many engines, and I more or less know what will work and what won't work for a fairly low speed engine such as I have designed here.


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## awake (May 5, 2020)

Thanks, Brian. I feel reassured that I am not the only one who finds it to be less than clear. I'll claim _maybe_ 5% understanding of what I have read ... but I can easily follow someone's example, and you clearly have just a bit of experience ...


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## Brian Rupnow (May 7, 2020)

So---What was the outcome of this exercise? Not what I would have liked, but I will explain. "Thumper", with it's larger bore is a lot more powerful than any of the other 1" bore engines that I tried to run the sawmill edger with. I can easily start the engine with the disengaged clutch driven by three rubber o-rings. With no o-rings in place, the engine idles at around 1000 rpm. With the load of the o-rings driving the clutch (while it is disengaged), the idle rpm's drop to about 800 rpm. However, the edger is designed to have an input of 2000 rpm driving the 16:1 gear reducer. This should turn the saw-blades at 1000 rpm, and turn the infeed rolls at a lower rpm so as not to over-run the saw-blades. I adjusted the engine to run at +/- 2000 rpm, and engaged the clutch. The engine took it all in stride, and didn't stall. There was a noticeable drop in engine rpm, but it drove the edger mechanism without any noticeable bogging. However, when I went to feed a board through the edger, the board would get about half way thru the saws, and then stall the engine. I repeated this about 10 times with different settings and adjustments, but it became plain that the new engine simply didn't have enough power. I have a theory, but at this time it is only a theory. With the ignition set to fire at 15 degrees before top dead center, the engine starts and idles very smooth, and revs up very well in response to opening the throttle. I have the feeling that at 2000 rpm, the timing is too slow for that rpm. The engine doesn't have any mechanism to advance the spark timing with changes in engine rpm. I believe that if I were to modify the engine so that as the throttle opened the ignition timing would advance automatically, the engine would be much more powerful at the 2000 rpm it is being asked for. I have decided to back away from this project for a while and do something else.  I will probably come back to this and redesign the engine to give it an automatic spark advance, but for now I'm burned out on it.


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## stragenmitsuko (May 8, 2020)

There are electronic programmable spark controllers available . 
Mostly used in performance engines but I can't see why it wouldn't work on a model . 
It takes a trigger wheel on  the crank wit a nmbr of teeth . Typical 36 . 
And a trigger on the cam to tell when the engine is in it's compression stoke  . 
Most of them will also accept a map sensor to measure engine load .
And it's all glued together with electronics and software . 

Pat


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## payner (May 8, 2020)

Hi Brian. Engine looks and sounds great , sorry to hear you are having trouble with driving the saw edger . Just a thought and I can't see any governor connected to the throttle . As the RPM drops off you want the governor to open the throttle similar to a flyball governor on a steam engine  to maintain RPM . Most small engines on lawn mowers , riding tractors , snowblowers etc . adjust the throttle under load and the ignition timing stays constant .
Just a thought .
Bill


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## Brian Rupnow (May 8, 2020)

Payner--This engine has no governor, but before I made my trials with it I had turned the throttle adjustment screw in to the point where the engine was running at about 2000 rpm. The edger grabbed the board and sent it through the first set of powered rollers, then about 3" thru the saw, and then when the board got to the second set of rollers the engine bogged down and quit. I will retry it later this week with a weaker set of springs on the last set of powered rollers.---I have also investigated adding a manual ignition advance. It can be easily done, but I've hurt my back and I'm setting here designing with a heating pad on my back.


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## payner (May 8, 2020)

Brian . That's the point I'm trying to make , your throttle should be connected to a governor. Set your RPM to 2000 ( no load ) as you load up the engine with the wood going through the saw , the RPM will drop , the governor will open the throttle to maintain the 2000 RPM . When the cut is finished and the RPM starts to increase the governor will start to close the throttle and maintain your 2000 RPM .
All small engines work this way except some outboard motors , they don't vary ignition timing like a car .
Bill


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## LorenOtto (May 8, 2020)

Brian Rupnow said:


> So---What was the outcome of this exercise? Not what I would have liked, but I will explain. "Thumper", with it's larger bore is a lot more powerful than any of the other 1" bore engines that I tried to run the sawmill edger with. I can easily start the engine with the disengaged clutch driven by three rubber o-rings. With no o-rings in place, the engine idles at around 1000 rpm. With the load of the o-rings driving the clutch (while it is disengaged), the idle rpm's drop to about 800 rpm. However, the edger is designed to have an input of 2000 rpm driving the 16:1 gear reducer. This should turn the saw-blades at 1000 rpm, and turn the infeed rolls at a lower rpm so as not to over-run the saw-blades. I adjusted the engine to run at +/- 2000 rpm, and engaged the clutch. The engine took it all in stride, and didn't stall. There was a noticeable drop in engine rpm, but it drove the edger mechanism without any noticeable bogging. However, when I went to feed a board through the edger, the board would get about half way thru the saws, and then stall the engine. I repeated this about 10 times with different settings and adjustments, but it became plain that the new engine simply didn't have enough power. I have a theory, but at this time it is only a theory. With the ignition set to fire at 15 degrees before top dead center, the engine starts and idles very smooth, and revs up very well in response to opening the throttle. I have the feeling that at 2000 rpm, the timing is too slow for that rpm. The engine doesn't have any mechanism to advance the spark timing with changes in engine rpm. I believe that if I were to modify the engine so that as the throttle opened the ignition timing would advance automatically, the engine would be much more powerful at the 2000 rpm it is being asked for. I have decided to back away from this project for a while and do something else.  I will probably come back to this and redesign the engine to give it an automatic spark advance, but for now I'm burned out on it.


I am sorry it didn't give you the power you thought it would right off the bat.


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## Brian Rupnow (May 8, 2020)

Loren---I am too. I have a couple of more tricks up my sleeve. This isn't dead yet. I'm just leaving things until my back feels a bit better.---Brian


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## LorenOtto (May 8, 2020)

I know how debilitating a back injury can be.  I am waiting to schedule my second surgery in five years.  Take care my friend.  Loren


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## teeleevs (May 9, 2020)

payner said:


> Brian . That's the point I'm trying to make , your throttle should be connected to a governor. Set your RPM to 2000 ( no load ) as you load up the engine with the wood going through the saw , the RPM will drop , the governor will open the throttle to maintain the 2000 RPM . When the cut is finished and the RPM starts to increase the governor will start to close the throttle and maintain your 2000 RPM .
> All small engines work this way except some outboard motors , they don't vary ignition timing like a car .
> Bill


I built a little tractor using a Suzuki 3 cylinder 2 stroke  engine, it was useless without a governor, as soon as the mower hit a tuft of grass it would die, with a governor it will mow grass at 10 kilometers per hour. Forty inch cut.


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## johwen (May 9, 2020)

Brian Rupnow said:


> Loren---I am too. I have a couple of more tricks up my sleeve. This isn't dead yet. I'm just leaving things until my back feels a bit better.---Brian


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## johwen (May 9, 2020)

Brian Rupnow said:


> So---What was the outcome of this exercise? Not what I would have liked, but I will explain. "Thumper", with it's larger bore is a lot more powerful than any of the other 1" bore engines that I tried to run the sawmill edger with. I can easily start the engine with the disengaged clutch driven by three rubber o-rings. With no o-rings in place, the engine idles at around 1000 rpm. With the load of the o-rings driving the clutch (while it is disengaged), the idle rpm's drop to about 800 rpm. However, the edger is designed to have an input of 2000 rpm driving the 16:1 gear reducer. This should turn the saw-blades at 1000 rpm, and turn the infeed rolls at a lower rpm so as not to over-run the saw-blades. I adjusted the engine to run at +/- 2000 rpm, and engaged the clutch. The engine took it all in stride, and didn't stall. There was a noticeable drop in engine rpm, but it drove the edger mechanism without any noticeable bogging. However, when I went to feed a board through the edger, the board would get about half way thru the saws, and then stall the engine. I repeated this about 10 times with different settings and adjustments, but it became plain that the new engine simply didn't have enough power. I have a theory, but at this time it is only a theory. With the ignition set to fire at 15 degrees before top dead center, the engine starts and idles very smooth, and revs up very well in response to opening the throttle. I have the feeling that at 2000 rpm, the timing is too slow for that rpm. The engine doesn't have any mechanism to advance the spark timing with changes in engine rpm. I believe that if I were to modify the engine so that as the throttle opened the ignition timing would advance automatically, the engine would be much more powerful at the 2000 rpm it is being asked for. I have decided to back away from this project for a while and do something else.  I will probably come back to this and redesign the engine to give it an automatic spark advance, but for now I'm burned out on it.


Hello Brian, If I can make a couple of suggestions firstly the reason it won't idle slower is most likely it is too advanced at that speed to run as a test retard it to say 10 degrees and check its idle and maybe the mixture too may be a bit lean. Secondly if you open the throttle as the load comes on and keep the revs at 2000 it should handle your sawing operation. As It is I would assume it is loosing power because as the revs drop with the sawing opperation the 15 degree advance is too much and is working against developing power.
Hope this helps
John From down under.


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## Willyb (May 9, 2020)

Brian
In no way was I suggesting that you run your engine unrestrained and have six or eight weeks of work go flying onto the cement floor and smash to pieces. I was merely asking your thoughts on this engines balance while running. I did ask if you had run it unrestrained but in no way was I suggesting it.
Willy


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## Brian Rupnow (May 9, 2020)

It's okay willy. I wasn't offended. Some of my engines would set on a table unrestrained and putt away all day without trying to move. Some of them would take right off and walk across the floor. I always bolt my engines down, because it's kind of a crap shoot---I never really know how well or how poorly an engine is balanced until I run them.---Brian


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## teeleevs (May 10, 2020)

johwen said:


> Hello Brian, If I can make a couple of suggestions firstly the reason it won't idle slower is most likely it is too advanced at that speed to run as a test retard it to say 10 degrees and check its idle and maybe the mixture too may be a bit lean. Secondly if you open the throttle as the load comes on and keep the revs at 2000 it should handle your sawing operation. As It is I would assume it is loosing power because as the revs drop with the sawing opperation the 15 degree advance is too much and is working against developing power.
> Hope this helps
> John From down under.


There are a few things that affect idle speed, the weight of the flywheel, (more is better), compression (less is better) valve timing and duration (must be a compromise with the speed requirements) I cut down a six cylinder Toyota motor to single, it would not run at all until I ground the cams away to allow a shorter duration, ignition timing the Suzuki 3 cylinder 2 stroke Jeep engine had no auto advance you had to set the dizzy up at the best spot.  Ted from down under.  Look after that back Brian, cheers.


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## Willyb (May 10, 2020)

Brian, If you want proper rpm control over your motor under a varying load you need a throttle controlled governor. Yes, there are many engines with dynamic ignition systems but I have never seen one that used that as their only/main speed control. If you look at today's small production motors like Lawn Mowers, Garden Tractors, Snow Blowers and Generators they all have some type of speed sensing throttle controll. Early lawn mowers used cooling air pressure pushing on a spring loaded plate connected to the throttle. This was simple and also quit sensitive. Today they use a set of fly weights spinning inside the crankcase that is directly connected to the throttle and uses variable spring pressure to set the motors rpm's.

Willy


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## Brian Rupnow (May 12, 2020)

Since I want to run Thumper at a much greater speed than at idle, I need to be able to adjust the timing of the engine. With a non adjustable ignition timing, the engine will run much faster than at idle, but it really doesn't have a lot of power at higher rpm. The cheap and quick way to address this is to mount the ignition points on a separate timing plate which can be adjusted with an attached lever. A #10 shcs and spring washer go thru the slot into the frame of the engine so the adjustable timing plate will hold itself in whatever position you set the handle at.  This current set up will give an adjustment range of a total 120 degrees. It is pivoted on the crankshaft. This set-up will allow me to advance the engine timing when it is running at a higher speed. I have hidden the near side flywheel here so that the ignition advance mechanism is visible. The ignition points are attached to the timing plate and rotate with it, thus advancing or retarding the ignition.


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## William May (May 13, 2020)

teeleevs said:


> Hope this one works, Must apologize for the dog wanting to get in on the action.



Very cool video. Are there any drawings for the full size track runner?


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## William May (May 13, 2020)

William May said:


> Very cool video. Are there any drawings for the full size track runner?


Also, I am fluent in Dog. Sam just wants to know if he can borrow the motor trolley and go cruising for chick poodles.  I don't blame him. That's a really amazing machine! 
Also, the high speeds your friend is running at, would that make him a Scofflaw? Or a Galoot?


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## William May (May 13, 2020)

Brian Rupnow said:


> I have a number of requests for plan sets. Tomorrow I will open each drawing and save it as a pdf file so that no special software is needed to open and print the drawings. This will take a couple of hours, as there are 60 drawings and some of them are multiple sheets. I charge $25 Canadian funds, payable to Paypal. If you send money to [email protected] at Paypal, they will notify me and I will send you a zip file with all of the part and assembly drawings. Please specify that it is the drawing set for "Thumper".---Brian Rupnow


You are an excellent engineer! The machine works great right off the bat!
Do you have other engine plans that you sell? I will be sending you an order for a set of "Thumper" plans tomorrow! I really enjoyed this build and the accompanying log and photos!


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## teeleevs (May 13, 2020)

Brian Rupnow said:


> Since I want to run Thumper at a much greater speed than at idle, I need to be able to adjust the timing of the engine. With a non adjustable ignition timing, the engine will run much faster than at idle, but it really doesn't have a lot of power at higher rpm. The cheap and quick way to address this is to mount the ignition points on a separate timing plate which can be adjusted with an attached lever. A #10 shcs and spring washer go thru the slot into the frame of the engine so the adjustable timing plate will hold itself in whatever position you set the handle at.  This current set up will give an adjustment range of a total 120 degrees. It is pivoted on the crankshaft. This set-up will allow me to advance the engine timing when it is running at a higher speed. I have hidden the near side flywheel here so that the ignition advance mechanism is visible. The ignition points are attached to the timing plate and rotate with it, thus advancing or retarding the ignition.


Hi Brian, looks great but that won't give you enough power for your job without a governor,  simplest way would be to fit an air vane behind the flywheel/fan connected to the throttle with a spring opening the throttle and the vane closing it. A mechanical governor is more reliable but the air one should allow a power increase as the load comes on. Can vary the speed by varying the spring tension.  Ted from down under


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## Brian Rupnow (May 13, 2020)

I scrounged around in my flat plate box to find a piece of material to make this manual spark advance from, and the only bit I found close to the right thickness had some rust pits on it. Oh well, that will be hidden in behind the flywheel. I have to call my nut and bolt store and see what they have in the line of Belleveille spring washers so that I can put them under the head of the bolt which goes thru the slot into the engine frame to keep the spark advance from slipping and resetting itself.


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## Brian Rupnow (May 13, 2020)

And the ignition timing handle is added. One picture shows the entire engine set up on an angle plate in my milling machine so I could drill and tap the single #10-24 thread thru the side of the engine for the bolt that keeps the timing handle in place. The other picture shows the engine setting on my side table with the installation completed. Tomorrow I will set it up to run and see how big a difference the timing makes to the power output.


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## teeleevs (May 13, 2020)

Brian Rupnow said:


> I scrounged around in my flat plate box to find a piece of material to make this manual spark advance from, and the only bit I found close to the right thickness had some rust pits on it. Oh well, that will be hidden in behind the flywheel. I have to call my nut and bolt store and see what they have in the line of Belleveille spring washers so that I can put them under the head of the bolt which goes thru the slot into the engine frame to keep the spark advance from slipping and resetting itself.


Looks good, keep up the good work.


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## a41capt (May 14, 2020)

Excellent work around Brian.  Looking forward to seeing Thumper earn it’s keep!

John W


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## Brian Rupnow (May 15, 2020)

I just went down to my "Nut and Bolt" store and picked up a dozen Belleville washers. For those of you who haven't heard of them, they are a spring steel flat washer, which have a curve built into them---They're not really flat. In situations like I have with the new timing handle, you want it to stay wherever you set it and not move out of adjustment from engine vibration. However, you do want it to swing freely "by hand" but then remain in place. These Belleville washers are the answer. You can stack 4 of them together and put one ordinary flat washer next to the part which has the slot cut in it. They work very well to put a constant "pre-load" on the part which must be moved by hand but not by engine vibration.


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## William May (May 15, 2020)

Brian Rupnow said:


> I just went down to my "Nut and Bolt" store and picked up a dozen Belleville washers. For those of you who haven't heard of them, they are a spring steel flat washer, which have a curve built into them---They're not really flat. In situations like I have with the new timing handle, you want it to stay wherever you set it and not move out of adjustment from engine vibration. However, you do want it to swing freely "by hand" but then remain in place. These Belleville washers are the answer. You can stack 4 of them together and put one ordinary flat washer next to the part which has the slot cut in it. They work very well to put a constant "pre-load" on the part which must be moved by hand but not by engine vibration.


Brian, 
I bought a set of plans for the "Thumper" engine, and you sent the downloads. I know I got it because I looked at it. When I got back from going to get a memory stick to download it for printing, the plans were gone. I think I inadvertently deleted them. Could you please send them to me again? I sent an e-mail to you, but I think it didn't go through.
Thanks!
Bill


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## Brian Rupnow (May 15, 2020)

For those who bought a set of plans for this engine----This is the timing handle that I added to the engine.---Brian


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## a41capt (May 15, 2020)

Brian Rupnow said:


> I just went down to my "Nut and Bolt" store and picked up a dozen Belleville washers. For those of you who haven't heard of them, they are a spring steel flat washer, which have a curve built into them---They're not really flat. In situations like I have with the new timing handle, you want it to stay wherever you set it and not move out of adjustment from engine vibration. However, you do want it to swing freely "by hand" but then remain in place. These Belleville washers are the answer. You can stack 4 of them together and put one ordinary flat washer next to the part which has the slot cut in it. They work very well to put a constant "pre-load" on the part which must be moved by hand but not by engine vibration
> 
> My 1970 Maico motorcycle clutch used stacks of Belleville washers as clutch springs. Damn near bullet proof and a positive engagement, but a real SOB to get the stacks right without having it slip or be too tough to actually pull in the lever!


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## Brian Rupnow (May 16, 2020)

Today I started and ran "Thumper" with the new ignition timing handle in place. Did it make a difference?--No, not really. I could manually adjust the timing thru a range of about 75 degrees.  With the engine running under no load conditions, I couldn't really see it affecting the way the engine ran. The engine ran good, but it ran good before I added the ignition timing handle. I have one more test to make, and then I will put this thread to bed. I want to set the engine up to run my sawmill edger, and see what difference the timing handle makes when the engine is under a load. If it does make the engine run stronger I will post a video of the engine running the edger and edging boards. If it doesn't make any difference to the power under load I will let you know.


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## awake (May 16, 2020)

Brian, what RPM was the engine running as you made the adjustment? I've wondered if that affects whether a difference is noticeable.


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## Mike1 (May 16, 2020)

Brian, I'm thinking that maybe heavier flywheels may help to keep the engine going and create more torque when it comes up against the timber.
I'm no expert in the mechanics of flywheels and torque just my bit of practical thinking, and I want to see your edger whipping through those planks !!
Mike1


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## bruedney (May 16, 2020)

My personal uneducated opinion is that the issue is a combination of timing and carburetion. I have read some posts on RC forums about issues using 2 stroke carbs on 4 stroke engines.


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## johwen (May 17, 2020)

Brian Rupnow said:


> Today I started and ran "Thumper" with the new ignition timing handle in place. Did it make a difference?--No, not really. I could manually adjust the timing thru a range of about 75 degrees.  With the engine running under no load conditions, I couldn't really see it affecting the way the engine ran. The engine ran good, but it ran good before I added the ignition timing handle. I have one more test to make, and then I will put this thread to bed. I want to set the engine up to run my sawmill edger, and see what difference the timing handle makes when the engine is under a load. If it does make the engine run stronger I will post a video of the engine running the edger and edging boards. If it doesn't make any difference to the power under load I will let you know.


Hi Brian, John again, If you set the engine
 speed at say 2000rpm with the timing in retard and then slowly advance until the engine reaches max rpm advancing beyond this point will not increase the torque, but over advancing will reduce torque. You should also adjust the mixture prior to adjusting the timing. The speed of burning the fuel will vary engine rpm also fuel mixture and timing both need to be adjusted to find the best settings. The idea is to get maximum cylinder pressure occurring at around 5degrees after TDC. Spark plug positioning can also vary the pressure front also. Central position being most likely the best or shortest distance to the extremities in the combustion chamber. In smaller engines the increments of change will be very small also. Best wishes as it is a lovely build  and a great design,very compact.
John


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## awake (May 17, 2020)

bruedney said:


> My personal uneducated opinion is that the issue is a combination of timing and carburetion. I have read some posts on RC forums about issues using 2 stroke carbs on 4 stroke engines.



That's an interesting thought. I've read that a smaller-throat carburetor results in an engine that is easier to start, but will develop less power. Perhaps there is also an interaction between the throat size and the ignition timing.


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## teeleevs (May 17, 2020)

Mike1 said:


> Brian, I'm thinking that maybe heavier flywheels may help to keep the engine going and create more torque when it comes up against the timber.
> I'm no expert in the mechanics of flywheels and torque just my bit of practical thinking, and I want to see your edger whipping through those planks !!
> Mike1


It needs a governor to do uneven loads


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## Brian Rupnow (May 17, 2020)

I have a few things to say about this engine, and immediately after I do I am going to go out into my main garage and try it one more time running the edger with the new manual ignition timing handle to see if it does make the engine run stronger or not. Firstly, I am completely blown away by the compression this engine has with the rings  purchased from Debolt. Secondly, the flywheel fans do move enough air to constantly be moving air over the cylinder fins and dissipating the heat. They're not going to blow your hat off, but they are moving the air. Also, there is no measurable load imposed on the engine by these fans. (At least not with any equipment that I have). I will not be building a governor for this engine. The engine has been a complete joy to build and run, and even if it doesn't ultimately have enough power to run the edger, the engine has went together and ran easily.


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## Brian Rupnow (May 17, 2020)

And that's all she wrote. Time to move on to a different project.---Brian


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## johwen (May 18, 2020)

Brian Rupnow said:


> And that's all she wrote. Time to move on to a different project.---Brian



Just another thought Brian why not change the gearing either a smaller pulley on the engine or a larger one on the edger and run the engine at a higher speed to compensate for a slower edger may do the trick. Don't give up! cheers John.


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## Peter Twissell (May 18, 2020)

Brian, I can understand your frustration and there is a right time to step away from a project and turn to something fresh.
I have several projects running in parallel. As soon as the one I'm working on starts to feel like work, I'll switch to another. That way, every part is made with enthusiasm.
Maybe some element of a future project will provide inspiration to come back to this one.
Even so, you have built a very nice engine which runs well - no reason to expect any more.


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## awake (May 18, 2020)

Peter Twissell said:


> Even so, you have built a very nice engine which runs well



Amen to that. It's a lovely design!


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