# Cogsy Builds Rupnow Engine



## Cogsy (Jul 21, 2013)

After many recent trials and tribulations, I've finally managed to make a proper start on my build of Brian's fantastic Rupnow I.C. Engine with Governor. While I'm hoping I will progress quickly, realistically I expect this build might take me quite a while.

Due to a current lack of available funds (one more tribulation ), I haven't been able to get hold of any aluminium plate of the proper size yet, so I'm going to be jumping all over the plans and making whatever I've got the material for first. 

First up then, I had these bits of 1020 bright steel to turn into flywheels. As you'll see, I had some difficulty machining it. 








Here they are, warts, chatter, witness marks and all... I just can't seem to get along with steel. I'll paint them up all pretty later though, so I'm not overly worried about their appearance yet (and they do look a little better in the flesh than in the photo). The shafts are only in place for work-holding - they're not what I'll be using.







Next up will be the crankshaft between the flywheels, but this log is being done in real time, so I'm not sure when the next installment will be.


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## Brian Rupnow (Jul 21, 2013)

Cogsy--First, let me say "Welcome Aboard"!!! Secondly, you are very brave to follow a build on an as yet unproven engine, but I am working on that. Lack of funds--Lack of time.--We've all been there at one time or another. It sucks, but---it passes. Get some 180 grit and some 220 grit emery paper--That will remove 95% of your chatter marks, and don't feel bad. Every builder on this forum gets chatter marks at one time or another, and every one of them is well acquainted with the magic of emery paper. I wish you the greatest of success, and thank you for pursuing this build.---Brian Rupnow


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## Cogsy (Jul 25, 2013)

Got a little bit more time today, and managed to make the crankshaft from a bit of mystery metal I had laying around.

I wouldn't say it was all that difficult to machine, but there are lots of places to make mistakes and it took quite a while for me to get it right. It fits where it's supposed to, all the holes line up and the bolts pick up their threads so I'm very happy with it.






Not sure what part I'll move onto next, maybe the valves and cages or possibly even the gears. Hoping to get at least a handful of parts done over the weekend.

In case you're wondering, the bit of plate in the background will be the base of the ball turning tool I need to make so I can make the governer balls. At last I have an excuse to make a ball turner!


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## Brian Rupnow (Jul 25, 2013)

Parts is parts Cogsy. They all add up to an engine, eventually. Its a bit like eating an elephant---One bite at a time. Good work.----Brian


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## rcfreak177 (Jul 25, 2013)

Looking good Cogsy,

Watching with interest, keep up the good work mate.

What sort of bike does that front wheel in the first post belong to?

Baz.


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## Cogsy (Jul 25, 2013)

Thanks Baz. That's my wife's front wheel on her 2004 YZ85 big wheel. I've got a couple of little Chinese quads tucked away for the kids as well, and a 140cc pit bike for my eldest daughter. Mine is 2007 KX250 2 stroke. Just wish I had the time to get them all dirty...


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## Path (Jul 25, 2013)

Great start and looking nice.

Will following your build with great interest.

Thanks for sharing.

Pat H.


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## Cogsy (Aug 3, 2013)

My collection of parts is slowly increasing, although not quite at the rate it should be.

I now have the cam and crank gears made, and one of the 2 crank spacers (the other one will only take a few minutes, I just forgot about it).

I picked up a nice chunk of cast iron bar, so I thought I'd whip up the cylinder. Seems easy enough looking at the plans, but I soon realised I didn't have the proper tooling to bore 2.7 inches deep :wall:. With crossed fingers I decided to give it a go anyway, and it was a painful experience.

I drilled a 1/2" hole to the required depth and then used a less than rigid boring bar stuck way too far out of the toolpost, to take very slow 5 thou cuts up to the 0.875" bore size, with MANY spring cuts every 40 thou, and many more approaching the final size. I'd guess I may have made as many as 150 slow passes before I was done. The good news is that I do now have a useable cylinder, once I've honed and lapped it.

Here's a pic of all the parts so far. It's winter here in Australia, and I noticed just a little surface rust creeping onto the flywheels. Imagine my surprise when I came inside tonight and downloaded this photo off my camera I swear the rust is barely visible to the naked eye.






I should have a few hours tomorrow to get some more done, including getting rid of that rust, so hopefully I'll have another update tomorrow night.


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## Brian Rupnow (Aug 3, 2013)

Al---My digital camera does that too.---Picks up all kind of horrible stuff that you don't even notice with the naked eye. I find it helps to give anything steel a wipe with an oily rag if its not being installed right away. What you found when boring your cylinder is exactly why I wait until after the cylinder is bored to make my piston. That way if you do wander a few thou over on the bore diameter to get it cleaned up properly, you simply machine the piston a few thou over to match it. I'm not sure whether you posted your intentions or not--are you going with the water cooled engine or the air cooled.---Brian


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## Cogsy (Aug 3, 2013)

Brian - I never make the piston first for the same reason. I'm not sure what's going to happen when I attempt a multi-cylinder and have to make multiple bores identical, I imagine I'll end up with lots of scrap pieces...

I'm going to be building the water cooled version, I just like the look of a water hopper better for some reason. I haven't machined the bolt reliefs on the cylinder yet - I want to wait until I make the head first, but I still haven't got material for it. Tomorrow I may get a piston and cast iron rings made, and finish off the last 25% of the conrod that I started but put aside to get the cylinder done. I don't know why I dislike making conrods, but I have to be in the mood to get them done.

Good luck with your electronic ignition. I'll be interested to see your design for mounting it. I have a rough idea in my head of how I was going to mount mine, but its a ways off yet. The el-cheapo Chinese one I have on my Upshur works well, but for some reason altering the timing by as much as plus or minus 20 degrees has very little effect on engine performance, although I am still trying to fine tune all sorts of things on that engine so it may become more responsive as other gremlins are sorted.


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## Brian Rupnow (Aug 3, 2013)

Okay Al--That was what prompted my question----I didn't see the relief scallops for bolt clearance cut out of your cylinder. Initially I didn't think I would need them, but I just couldn't "squeak" the bolts past the major diameter of the cylinder and get them started to thread into the water jacket without those relief scallops.---Brian


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## Cogsy (Aug 3, 2013)

Now I'm really glad I haven't added them yet. I didn't want to own up to it but I bought the wrong size cast iron and I had to take the flange down to 1.4" to clean it up. I figure I'll just have to match the water hopper to the new diameter. Possibly with the slight reduction I may not need the scallops at all.


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## Path (Aug 3, 2013)

Al,

Nice to to see that you are making progress.
I have yet to start mine ... but I'm making progress getting to starting line and should be there soon. 

Pat H.


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## Cogsy (Aug 3, 2013)

Thanks Pat. I have no doubt you'll catch up and pass me pretty quick. 

It is a fun engine to build so far, and very different from anything I've done before. I'm having to learn all new machining techniques which makes it an even more rewarding experience. 

I'll be watching your build thread with interest.


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## Swifty (Aug 3, 2013)

Hi Cogsy, great to see some more progress. Regarding boring bars, I've made quite a few in the past from round stock with a hole towards one end to take a broken 1/4" HSS cutter, held in by a grub screw. Just choose some round stock to suit the hole size, allowing for cutter stick out.

Paul.


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## Cogsy (Aug 3, 2013)

Thanks Paul. I hadn't even thought about making one but it sounds like a great idea. My to-do list just got a little bigger


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## Cogsy (Aug 4, 2013)

Just a quick update today and no photos. Sorry, I'll include them with my next progress report.

I got the cylinder nicely honed and it's ready to go. I used my little 2 stone brake cylinder hone - worked a treat and didn't take long at all.

Then I made the crank spacer I forgot yesterday, twice. Why twice you ask? I trusted my memory rather than taking the two steps to look at the drawing and cut it too short :wall: Of course I was making it from an offcut and there wasn't enough meat left on it for a second one, so I had to start from scratch. Lucky it's an easy part to make.

After that fiasco I managed to carve out a pretty decent piston from a horribly 'gummy' piece of Ali bar that I've got about 6 feet of. I almost had to continually flood it in WD40 just to part it off. I'm slightly deviating from the plans here and running 2 cast iron rings, so I used my best judgment on groove placement.

Finally I cranked out half a dozen cast iron rings, as it takes no more time to make extras. I've only split and heat treated the two I need at this stage until I make sure I've got the right amount of ring tension on them. If these two work then I'll split and treat the rest as spares.

And that was all I got done today, even though I spent most of the day in the shed and it felt like I was working pretty quick, but somehow the day just disappeared on me. Fingers crossed I'll get some more time during the week.


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## Brian Rupnow (Aug 4, 2013)

Cogsy--I generally use 6061 heat treated aluminum for all the material on my engines, mainly because that is what my supplier stocks. It machines very clean with no gumminess. I know there are many other grades of aluminum out there, some gummy and some not. As long as you were able to get the piston carved to size, probably it will be fine,---its just outside my experience. It will be interesting to see what happens to the aluminum when you go to lap it into the cylinder.---Brian


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## Cogsy (Aug 4, 2013)

Brian - I'm not exactly sure what you mean by lapping the piston into the cylinder (I'm pretty new to all this machining stuff remember). I just went off what I learned from my Upshur build and made the piston around 0.001" smaller than the bore (for expansion maybe?) and figure I'll let the rings do the sealing. Nevertheless, with no rings on the piston it slides nice and smoothly through the bore and sealing off the end with the palm of my hand produces reasonable compression/vacuum. Please let me know if I've got my thinking wrong and I'll remake the piston if necessary. Thanks.


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## Brian Rupnow (Aug 4, 2013)

Cogsy--You may be alright without lapping. I think I covered it in my thread on the Rupnow engine, but I will go over it again and give you the condensed version.--After I have machined and honed my cylinder, much the same as you have done, the inside of the cylinder will still be full of microscopic grooves from the honing process. If you are going to run cast iron rings, this is good, because those microscopic grooves will hold a small amount of oil to lubricate the rings, and will also act somewhat like fine sandpaper, to "wear the rings in" so they end up being a very precise fit to the bore of the cylinder. However, those same microscopic grooves left from honing are really bad news for a Viton o-ring, because they wear it away very quickly. That is why I lap the bore of the cylinder. I generally make a solid round lap about 3" longer and .001 to .002" smaller in diameter than the bore of the cylinder, and coat it with 600 grit carborundum paste. The lap is then worked back and forth thru the bore of the cylinder in a twisting manner from end to end to polish away the small ridges left by honing, and give an almost mirror like finish to the inside of the cylinder bore. Then I turn the piston to be about .001 to .002" smaller than the cylinder bore and repeat the process to polish the o.d. of the piston as well, and remove any "tight spots" that the piston may have in the bore. That is also the process used on steam engines which use a softer ring material than cast iron. It is also the process used on engines which don't use any rings at all. Since you are going to use cast iron rings, you may well be able to skip the lapping process completely with no ill effects.---Brian


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## Cogsy (Aug 4, 2013)

Thanks Brian. I did read your lapping procedure but somehow skipped over or forgot that you also lapped the piston in as well. Maybe it didn't sink in because I turn the piston either very slightly oversize or onsize to the bore, then polish it down to final size using finer and finer paper until it has a nice shine and is the proper size. Of course this nice finish is quickly ruined by the roughness of the bore, but at least I'm happy it started it's life smooth.

I don't intend to lap the bore any further, just based on past experiences with full-size engines and glazed vs honed bore performance. As you said, I'll have rough rings on a rough bore which hopefully will mean a nice sealing fit once they bed in together.


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## Brian Rupnow (Aug 7, 2013)

Cogsy--This is just a drop in to say Hi and offer up a word of encouragement. I am currently "breaking new ground" with my CDI ignition that I have purchased. ( I don't believe that my engine requires a CDI to run it, but I have always wanted to try one.) Cheers mate, keep up the good work. I will probably repeat this message to all the others who are building the Rupnow engine.---Brian


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## Brian Rupnow (Aug 23, 2013)

Cogsy---Any progress to report?  I'm checking up on all my co-builders today, and I haven't heard from you for a while. I hope everything is okay.---Brian


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## Cogsy (Aug 23, 2013)

Brian - I have been very slack with posting updates, but I have made some (slight) progress. This weekend looks good for engine building so I'll make sure I post something soon. Lately it's been a little 3 steps forward, 2 steps back, but a solid couple of days work should improve my completed parts pile.

I now have most of the materials I need, so my only excuse now is lack of ability/confidence. This engine WILL run, but I'm no longer confident of how good it will look compared to the others I'm seeing. More to come soon.


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## Cogsy (Aug 24, 2013)

I did promise an update but unfortunately it's not going to happen today. I just got a call that my Dad (who lives in the country) has managed to half chop his left thumb off with a power hacksaw (it wasn't running at the time. Long story). So I'm off to help them get some stuff sorted. Sorry.

At least I got one shop day yesterday...


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## Brian Rupnow (Aug 26, 2013)

Hope your dad is okay---Brian


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## Cogsy (Sep 1, 2013)

Well it's been a long time coming, but finally I have a bit of a progress report.

Firstly, Dad is doing well, his thumb is pretty well secured in place and his other bangs and bruises will heal.

Now, on to my engine. If you recall, I had limited materials available, so I had to make bits that I had stock for. I machined up the valves from the shaft of an old printer (wonderful sources of all sorts of useful bits), turning about 1/4" at a time to eliminate flex. I made 3 (nearly) identical, and will make a valve seat cutter from the extra one. I also followed Brian's lead and left lots of extra material on the head end so I've got something to hold onto for lapping.

I spun down a section of 7/8" brass I had and machined up the valve cages and valve retainers. It might seem like a waste of material to make tiny parts from an oversize bar, but I really wanted to keep moving forward. These were nice and easy and I had no issues.

Next up I decided to satisfy my own curiosity and see what would happen if I tried to make miter gears using my home-made gear 'hob'. I just couldn't visualise what it would do with 5 cutters all cutting on a 45 degree angle. So I chucked up another piece of the 7/8" brass, made a couple of blanks and had a go. The results are...weird. The teeth are a bit strange looking, and they all mush together as they get towards the centre, but the bits that run together seem like they may work. I'll probably end up trying them out before I purchase a real set.

Flushed with success of sorts, and with a new injection of fresh material, I started on the cylinder head. Cutting and shaping was my normal tedious affair, with much checking and measuring and I managed to approximate the correct shape. I then centered it under my mill and bored the counterbore - almost a full millimetre off centre! I didn't pick up my error at that point though and continued on... As I had the centre of the counterbore, I used the wonderfully dimensioned plans to move all around the head boring the valve cage holes, milling the spark plug slot and drilling the bolt circle. I had to keep returning to the centre after each operation, just to make sure I was still on track, as I haven't milled from a central point like that before. All went well and I was happy that my head was looking good. Then  I drilled and tapped the spark plug thread and glued the valve cages in place.

This post is getting very long so I'll split it here. Next up - the water hopper!


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## Brian Rupnow (Sep 1, 2013)

Cogsy--That is a wonderful bunch of progress... So--Did you discover your 1mm out of center before you drilled all the rest of the holes. Is the head ruined or are you going to be able to use it?--We love pictures!!!--Glad your dad still has all his digits!!!-Brian


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## Cogsy (Sep 1, 2013)

I picked up a nice chunk of 5083 ali about 2" x 2-1/2" x 8" and spent what felt like 2 hours hand hacksawing a lump off it. Then I squared it up on the mill and faced it to just oversize, to allow for my any errors I was sure to make .

I used my boring head on the mill to bore it, but it turns out I don't have a long enough cutter to bore as deep as I needed to, so I had to come in from both sides. I was concerned about doing that but it worked for me this time. Once I had the bore and both end steps machined, I hogged out most of the pocket with drills, then milled the pocket to shape.  After that I cheated and used transfer punches to mark, drill and tap the bolt circle from the head to the hopper. It was at this point that I discovered the off centre counterbore on the head :fan:. Once I'd finished my tantrum, jammed most of my hair back into my scalp and had a good think about the problem, I came to the conclusion that I may still be able to use the head as-is, but I won't be blending the water hopper to suit, in case I have to make another head in the future. I MAY make another head anyway, even if this one does work, but not just yet. 

Another slog with the dreaded hacksaw yielded a blank for the hopper lid and a square blank for the rear water hopper retainer. The lid was a fairly straightforward piece of machining (once I worked out how to hold the piece at the correct angle) and I got that done quickly. The square blank for the retainer I drilled and mounted on a mandrel in the lathe. I'm used to interrupted cuts from my experiments with a wood lathe years ago and it was an easy job to turn it round. Then it was on to the mill to open out the bore. Again I used transfer punches to mark the bolt circle and finish the retainer by drilling and countersinking the bolt circle. Then I drilled and tapped the hopper (transfer punches again) and everything bolts together nicely.

Turning back to the cylinder head, I drilled the ports and drilled and tapped the mountings for the carby and exhaust. The only thing left to do on it is the 3 holes for the rocker arm mount to bolt to. as you are no doubt aware by now, I need to use transfer punches wherever possible to have a hope of bolt holes matching up, so I needed the rocker arm mount at this point.

I needed a piece of mild steel 5/16" x 3/4" x 1-3/4" and I came up with a length of keysteel that was big enough. It was 1/2" thick but I milled it down to size. What I first thought was a simple little bracket turned out to have a 17 degree angle through half of it and really tested both my drawing reading ability and my machining capabilities. Don't get me wrong, the design and drawing are perfect, I just haven't had much experience with such technical items. Possibly the best part of this project so far has been how much I'm learning and extending my abilities.

Anyway, I spent a good chunk of today (fathers day here in Australia) out in my shed carefully extracting a complex rocker arm mount out of a lump of old keysteel. Happily, it turned out well, although maybe slightly different to the plan.

Next up I have to fit the rocker mount to the head, then it'll be onto either the push rod guide or the sides and base. Included in the photos below is the piston complete with cast iron rings, and the only half of the conrod that I want you to see . Fingers crossed my next update won't take as long as this one has. Thanks for looking!


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## Brian Rupnow (Sep 1, 2013)

Bloody MARVELOUS!!!  Cogsy---This is exactly how people become good machinists. --By screwing up, hating yourself for it, and then plunging onward. Next time, you will remember that screw up, and take extra care, whatever you may be doing.--Its just blind good luck that the screw up happened on something of your own, and wasn't a machine shop job, where you would have to go over and tell the shop foreman that you had messed up. Great progress, great pictures, and a great recovery!!!---Brian


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## Swifty (Sep 1, 2013)

Great work Cogsy, it's really coming together now. As to the bevel gears, you can't use a hobb to cut the teeth as it machines material off the teeth that are already cut, I tried it! That's when I bought a set of cutters. I don't have a power saw for metal either, so it's a lot of hand hack sawing on everything.

Paul.


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## Brian Rupnow (Sep 1, 2013)

Good Lord Guys!!! If I had to saw my material by hand, I would have never gotten into machining. I bought an old Jet 16" wood bandsaw and put a triple reduction on it to slow it down enough to cut metal with a bi-metal blade.


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## deverett (Sep 2, 2013)

Another one here who uses Armstrong's Patent.  No room in the workshop for a power hack or band saw.

Dave
The Emerald Isle


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## gus (Sep 3, 2013)

Hi Cogsy.Your engine is about all done up.Cogsy will be third.Looks like Gus will the number 9 to get his engine running.He is  the silent killer. I concede.
Gave up two day fishing trip to cut two pulleys.Took two hours to remove excess metal. Its true pulleys just done at 5pm.


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## Cogsy (Sep 3, 2013)

Don't worry Gus, it's not a race but I think you'll beat me anyway. I still have the side plates and base, push rod guide, push rod, cam, spark plug, ignition, exhaust, carby, flywheel shafts and probably many other small parts to go. I also have other commitments conspiring to keep me out of the shed for a while.

I did manage to get a useable rocker arm machined out of a 1/2" brass round bar today (I snuck it in while I was supposed to be making a part for work) but I won't be doing any more til the weekend at least, and next week is looking even worse! 

Keep up the good work on yours, it's looking great!


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## gus (Sep 4, 2013)

Hi Cogsy,
Was joking.Gus should be taking his sweet time . Was an old work habit,I could not shake off.
When there is a big pile of work,it must be cleared off before another pile comes.

Snucking.

I had so much brass/alum/steel/bronze bar stocks in the plant, Precision Engine Lathes,Bridgeports and Okamoto Grinders and no time to build engines.This was 1980----2001. A day's paper work leaves me totally exhausted and time to go home.

Today will be an easy day fitting up the flywheel.shafts,con-rod etc.


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## Cogsy (Sep 5, 2013)

I had a spare couple of minutes today, so I had a go at roughing out the side plates. A few million hacksaw strokes later, give or take a few, here they are. I stuck my rocker arm from the other day in there as well.






They're really roughly dimensioned/shaped, but I think the hard part's done. 

Good news - my work has fallen through for the weekend so I'll be getting something done on my engine after all. Pity about the money but you can't have everything. Roll on Saturday!

I also had a close look at my hobbed miter gears and Swifty is absolutely right - they're useless after all. Now to decide whether to buy a set of gears or a proper cutter.


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## Swifty (Sep 5, 2013)

Hi Cogsy, I bought my set of Mod1 cutters from CTC tools. http://www.ctctools.biz/servlet/StoreFront
I see that they are US$85 per set now, plus postage. They were about $100 all up in aussie dollars when I bought mine. You have to weigh up the cost of the gears against having a permanent set of cutters. I would strongly recommend getting the cutters if you can afford them.

Paul.


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## Brian Rupnow (Sep 5, 2013)

Nice work Cogsy--I'm watching.---Brian


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## Davewild (Sep 5, 2013)

Looking real good Cogsy.

Dave


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## Brian Rupnow (Sep 5, 2013)

Cogsy--About the bevel gears---A complete set of involute cutters is horribly expensive. I believe I paid about $500 for eight 24DP cutters and the proper arbor to run them on. They are primarily intended to cut spur gears with, although as Swifty has shown in the "Articles" section of this website, they can be used to cut bevel gears, although it looks like a pretty tricky set-up to me. You must also have access to a rotary table and dividing plates.--I'm not sure what tooling you have available, but you will need some kind of gear cutting set-up to cut the timing gears. I took what I considered the easy way out by buying the bevel gears that I used. My price here in Canada worked out to "around" $25 each, purchased from McMaster-Carr in USA.


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## johnny1320 (Sep 5, 2013)

Brian Rupnow said:


> Cogsy--About the bevel gears---A complete set of involute cutters is horribly expensive. I believe I paid about $500 for eight 24DP cutters and the proper arbor to run them on. They are primarily intended to cut spur gears with, although as Swifty has shown in the "Articles" section of this website, they can be used to cut bevel gears, although it looks like a pretty tricky set-up to me. You must also have access to a rotary table and dividing plates.--I'm not sure what tooling you have available, but you will need some kind of gear cutting set-up to cut the timing gears. I took what I considered the easy way out by buying the bevel gears that I used. My price here in Canada worked out to "around" $25 each, purchased from McMaster-Carr in USA.


 
Hi Brian, I tried to buy some parts from McMaster-Carr and they told me they won't sell to Canada, how did you get around that?

John


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## Brian Rupnow (Sep 5, 2013)

Basically, you find someone who has been in business since before this "Don't sell to Canada" edict was put in place. I have a large number of business acquaintances who do business with McMaster Carr every day. Its not that they won't sell to Canada--Its more like they will not accept new customers in Canada.---Brian


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## canadianhorsepower (Sep 5, 2013)

Brian Rupnow said:


> Basically, you find someone who has been in business since before this "Don't sell to Canada" edict was put in place. I have a large number of business acquaintances who do business with McMaster Carr every day. Its not that they won't sell to Canada--Its more like they will not accept new customers in Canada.---Brian


 
McMaster Carr  are retailer's if you search a little bit you'll find out the manufacturer's distributer in Canada and find out that GBS sell's their product at a lower price Give it a try


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## gus (Sep 6, 2013)

Hi Luc,

Will buy gears from GBS as a backup just in case my DIY conical gears won't mesh.

Been reading Ivan Law's book on "Gears and Gear Cutting. He has a good spread on cutting DIY Conical Gears. Swifty succeeded in cutting his own.So I am following.

The Hit & Miss Engine should be completed by end September/early October and will running w/o hitting & missing till the DIY gears are done.


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## Brian Rupnow (Sep 7, 2013)

Gus--I have a copy of "Gears and Gear Cutting" by Ivan Laws, and he gives a very thorough explanation of how to machine bevel gears using an ordinary involute spur gear cutter, using the same method as Swifty outlines in his excellent "How To" article. The next time I get an overwhelming urge to "machine something" I may try it, just to see if I can. I'm rather burned out on machining at the moment, but maybe later in the fall I'll try machining s set.--Brian


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## gus (Sep 8, 2013)

Brian Rupnow said:


> Gus--I have a copy of "Gears and Gear Cutting" by Ivan Laws, and he gives a very thorough explanation of how to machine bevel gears using an ordinary involute spur gear cutter, using the same method as Swifty outlines in his excellent "How To" article. The next time I get an overwhelming urge to "machine something" I may try it, just to see if I can. I'm rather burned out on machining at the moment, but maybe later in the fall I'll try machining s set.--Brian



Hi Brian,

At the age of 70 ,Gus is more proned to burned out. Pehaps I should have taken a good break before jumping in to build the Hit& Miss engine but it was so hard to walk away. After getting the major portions up and having the raw engine assembled and hand turned,my burnt-out seems cured. Now taking it easy with the minor parts.

Weekend fishing seems to eased off the Burnt-Out. This week-end fishing wasn't that good but was relaxing to see friends bringing up rod-benders and buying them dinner at the marina having their catch for dinner.

All set to cut the minor parts. Now totally refreshed.


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## Cogsy (Sep 11, 2013)

Just a quick update to let everyone know I'm still persevering. Side plates and bearing caps are progressing, in fact nearly done. As with almost every part of this build, I seem to be making small errors for some reason. This time I again misread a dimension and shaved the bearing caps where the bolts go through a little thin. They'll still work but I just keep buggering up somehow. I won't mention that I had a small crash with a slitting saw arbor - I'm trying to forget it.

Today was my wedding anniversary so I only had limited time to get onto the shed (that's why I didn't take any photos today) and I managed to make the push rod guide. Working carefully from the drawing, paying special attention to dimensions and...my bolt holes were not equally spaced from each end of the part . I scratched my head for a while, measured each bolt centre distance (all correct) and recalculated how far from the end the first hole was supposed to be (1/4" - it was correct) and it all checked out. So how come the other end was so far from the end??? Well, I started the job by making a blank to the dimensions given in the plan description at 3/4" x 5/16" x 2.860" and then went from there. However, on the body of the plan itself, the overall length of the piece is actually 2.680" . Once I shortened it up, my bolt spacing is spot on. It made me very happy to not be the cause of the error for a change, although I haven't heard about anyone else making the same mistake, so maybe I have to rethink how I read plans in future. I'm sure Brian will amend the drawing but it's really not a big deal.

That's all I got done but the weekend is only a couple of days away.


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## Brian Rupnow (Sep 11, 2013)

Cogsy--Just chalk that one up to Dyslexia. You are the first person to notice that.----Brian


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## petertha (Sep 11, 2013)

canadianhorsepower said:


> McMaster Carr  are retailer's if you search a little bit you'll find out the manufacturer's distributer in Canada and find out that GBS sell's their product at a lower price Give it a try


 
Please provide a web link. I tried googling 'GBS', not getting hits.


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## Brian Rupnow (Sep 14, 2013)

Cogsy--You must be just about ready to post an assembled picture of your marvelous creation. We are all looking forward to it.---Brian


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## Cogsy (Sep 15, 2013)

Brian Rupnow said:


> Cogsy--You must be just about ready to post an assembled picture of your marvelous creation. We are all looking forward to it.---Brian


 
Hmmm, I think your eagle eyes may have spied that most of my parts lack mating holes so far .

I must make a confession, up until this point I haven't actually been making an engine - I've just been making parts. However, with this gentle prod from Brian I've changed gears and started to make the parts fit together.

I'm fighting illness so I only got a couple of hours again today, but I drilled and tapped many holes and I nearly have it to a point where it can be mock assembled. As a side note, my transfer punches are feeling very neglected as of late. This build has forced me to learn to trust my dials and work from measurements instead of punch marks. Touch wood, it's working for me so far.

I also got the pushrod done today, but again, no photos. I'll take some soon, just have to work out how to unfocus the camera a bit .

Thanks for looking.


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## canadianhorsepower (Sep 15, 2013)

petertha said:


> Please provide a web link. I tried googling 'GBS', not getting hits.


 
here it is

http://www.gbs.ca/


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## gus (Sep 15, 2013)

Cogsy said:


> Hmmm, I think your eagle eyes may have spied that most of my parts lack mating holes so far .
> 
> I must make a confession, up until this point I haven't actually been making an engine - I've just been making parts. However, with this gentle prod from Brian I've changed gears and started to make the parts fit together.
> 
> ...



Hi Cogsy,

Take care. Get well soon.


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## AussieJimG (Sep 15, 2013)

It's not a race Cogsy, just do what you can when you can.

Jim


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## Brian Rupnow (Sep 15, 2013)

Jim is right. Its not fun to be sick, we all know that. Do what you can, when you're able, and I hope you feel better soon.--Brian


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## Brian Rupnow (Sep 26, 2013)

Cogsy---Are ya getting better??? I've been back and forth half a dozen times to physiotherapy trying to get the kinks out of my wretched old spine, but I'm doing better. Hope you are still making some progress on the engine. I see Luc finally got enough other peoples work done that he's turning out Rupnow engine parts again. Gus went away and got eaten by a big fish or something, but I'm sure he's going to post a runner soon. I didn't have much "real" engineering work all summer (which was just fine by me), but now I'm busier than a two headed cat!!! I've got three different customers all squalling to have their jobs done first, so I'm not doing much in my little machine shop right now. If yer not better, get better.---Brian


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## Philjoe5 (Sep 26, 2013)

Get better soon Cogsy.  Your statement:



> I must make a confession, up until this point I haven't actually been making an engine - I've just been making parts.



is too true.  First you make some parts, then you get to the point where they have to mate together.  I'm there right now too.  It can be frustrating but hang in

Cheers,
Phil


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## Cogsy (Sep 27, 2013)

Thanks for the words of encouragement guys. I have made a recovery, but I got a little sidetracked on another small project - http://www.homemodelenginemachinist.com/f36/yet-another-diversion-21834/ . Back on track now, and a promising weekend ahead. If I can sweet talk the lovely wife (she sometimes reads my posts...) I should get a decent amount of shed time. My focus will be on getting the parts mated up nicely, lapping the valves in and cutting the cam. With luck I'll have a nearly assembled engine to display by Sunday, except for the dreaded carby.


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## AussieJimG (Sep 27, 2013)

Cogsy said:


> ... except for the dreaded carby.



That's what I thought when I built my Bonzer so I wimped out and used one of Jan Ridders' Vapour carbys. That got the engine running with minimum fuss.

Later on I tackled the complicated carby and found that it wasn't so hard after all.

So if you run out of time, try the vapour carb.

Jim


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## Brian Rupnow (Oct 10, 2013)

Cogsy--Out of the ten good men who stepped forward to build Rupnow Engines, I think yours was the next nearest to completion. Swifty's is done (and beautifully)--Gus's is done and I have seen videos of it running. Yours was, I think, the next nearest to completion. Many of my other builders have "faded away". I hope you are still making progress.---Brian


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## gus (Oct 10, 2013)

AussieJimG said:


> That's what I thought when I built my Bonzer so I wimped out and used one of Jan Ridders' Vapour carbys. That got the engine running with minimum fuss.
> 
> Later on I tackled the complicated carby and found that it wasn't so hard after all.
> 
> ...



Hi Jim,

It's true most of us have Carbuphobia. Been trying out three versions------
Webster Original Carb,Webster OS .75 c.i. Carb,Brian's Carb(which I must have goofed/messed up converting to mm and the jet needle) and a bigger OS Carb which just won't match.
About to rework the Brian's Carb in Imperial Units and make a tool post grinder to grind needle.Another option would be beg/borrow/steal my wifey boss's big sewing needles
Fotos show two OS carbs.
The fuel line check valve works wonders. No more fuel dropping back to fuel tank and no air bubbles that can stop engine. Will incorporate check valve into all future engines. The Nemett Lynx IC Engine will have check valve.

Restarting engine was successful for every start. No more choking and flooding.


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## Swifty (Oct 11, 2013)

Hi Gus, looks like you might have to ease back on the oil for the cylinder, black spots everywhere. I wonder if you used a thicker oil, that it might flow a bit slower.

How's the work on the governor going, and don't forget, if you want me to give you a drawing for the mitre gears, just let me know the number of teeth and mod number.

Paul


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## gus (Oct 11, 2013)

Swifty said:


> Hi Gus, looks like you might have to ease back on the oil for the cylinder, black spots everywhere. I wonder if you used a thicker oil, that it might flow a bit slower.
> 
> How's the work on the governor going, and don't forget, if you want me to give you a drawing for the mitre gears, just let me know the number of teeth and mod number.
> 
> Paul



Hi Paul,

Please send mitre gear drawings. This beats reinventing the wheels.
Will add on 2T to the petrol. Cylinder Lube. is messy. 
Next week will rework Brian's Carb. To get the H&M going ,best to use same Carb. This way we can compare notes.


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## Swifty (Oct 11, 2013)

What module cutter are you going to use?
Don't want to hijack Cogsy's build, maybe you can send me a PM.

Paul.


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## Cogsy (Oct 18, 2013)

Brian Rupnow said:


> I hope you are still making progress.---Brian


 
My apologies - I have been AWOL lately, both from the forum and the shed.

I have mated up most of the parts that I have, although I still have to mount the cam gear/cam assembly. I am guaranteed some shed time this weekend, although the outlook is not good after that for a while, so I should make some progress.

As it stands, I need to make the baseplate (shouldn't take long), make something up to hold my ignition bits, finish off my half made spark plug, then move on to the carby and check valve. I do have some compression already and I expect that will improve once the first couple of shots are fired and the rings and valves bed in a little.

I promise I'll have some photos to show by Sunday night, and if all goes exceedingly well, I may even have a running engine by then (but it's a very long shot).

Thanks for checking in.


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## Cogsy (Oct 20, 2013)

As promised, I have a couple of photos at long last. I didn't get as much shed time as I hoped over the weekend, and I had a bit more to do than I thought, but progress has been made.

After several attempts at it, I have a spark plug which should work for an initial start (though I haven't tested it) but I'll need to make another that's a bit better proportioned, just for looks. The one in the photo isn't the new one, I forgot to put that in.

I also made an exhaust with a muffler/blast deflector of sorts, which looked really snazzy in my head, and it turned out horrible. Again, I'll use it to get the engine running then replace it with something that looks better.

The cam and gears are installed and working as they should, and I have the baseplate finished up good enough for now. I'm still not sure what the wooden base of the engine will be like, so I may end up rounding the corners or maybe chamfering the whole thing. I'll decide after I have a runner.

So I still have to mount the ignition and make up the carb. My plan says I'll get the ignition sorted during the week but the carb will have to wait until next weekend at least. I also need to make up something so I can spin the engine with an electric drill to get it started. I don't know what yet but I'll give it some thought.

Until next time - thanks for looking!


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## Philjoe5 (Oct 20, 2013)

Al,
That's a fine looking engine you've made.  I'm sure you will work out the final details to get it running

Cheers,
Phil


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## Brian Rupnow (Oct 20, 2013)

Cogsy--You are doing a wonderful job!!! I am sure you will soon have the fourth running "Rupnow Engine" in the word. You will become a member of a very elite club that so far has only 3 members. ---Brian


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## Swifty (Oct 20, 2013)

Looking great Cogsy, yours will be the second water cooled version.

Paul.


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## wagnmkr (Oct 20, 2013)

Looking Good ... looking forward to seeing it go.

Cheers,

Tom


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## gus (Oct 20, 2013)

Great looking engine.You beat me hands down in finishing.The water jacket looks great too.

Gus is taking a week's break in Thailand 22----28 Oct. The hotel has good WiFi to follow up on your progress.

Fishing was very bad over the weekend. Nearly got caught in a flash flood. 77mm in 2 hours is just crazy.


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## Cogsy (Oct 28, 2013)

No progress to report (again) but for a good reason for a change. I just received my new (to me) lathe on a very large bench, and my shed is now so full I can't step in the door. Now I need to dig out my engine crane to hoist my mill/drill onto the new bench, move my old lathe from it's position and shoehorn the new bench into place. Once all that's done I can move on to adjusting the new lathe and working out how to use it, then get back into engine building.

That all sounds easy, but being in the middle of a rebuild on the V8 turbo diesel in my furniture truck as well, I'm busier than a one legged man in an a$$ kicking contest...


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## Path (Oct 28, 2013)

Al,

Thanks for the update. Looking back on your progress I see some great workmanship. It will be worth the wait. Looks like you will need to post a few pictures of your new lathe and workshop. 

Pat H.


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## Cogsy (Nov 3, 2013)

I got my mill/drill onto the new bench and managed to rearrange enough stuff to fit the new bench into position. As you'll see by the warts-and-all photos, I still need to do some major housekeeping to get everything into shape.

In the shortish term, I plan to build a further extension/lean-to off the side of the main shed to get rid of the motorbikes and some other storage type stuff. Soon I will be commencing work on the project car and I'll need all the room I can get for that. 

Note to self - NO MORE PROJECTS!!!

Here's my little lathe, now relegated to just thread cutting and making pens.






Here's the new bench, with mill installed and the new lathe (I know, it's got a milling attachment, but I won't use it, I promise).








Now some pics of my 'work area'...






















And finally, a stitched together, overall impression of what I'm dealing with.






My truck motor is now 100% back together, so now I've just got to put the 1 ton beast back in the truck. Once that's done, a tidy up in the shed and I'll be back on my engine.


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## AussieJimG (Nov 4, 2013)

I feel much better now Cogsy, I was feeling a bit embarrassed by all the pristine work areas shown by other people. 

Now I know that there are other blokes like me in the world.

Thanks

Jim


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## gus (Nov 4, 2013)

There are occasions when one too many machining errrors happened/tools misplaced and hard to locate means it time to review housekeeping.Housekeeping is actually relaxing and it takes your mind away from tough machining job.

The current H&M Engine did suffered a few machining errors because of the rush and bad housekeeping.


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## Cogsy (Nov 17, 2013)

Well I've finally started to make chips on my Rupnow engine again. I put the motor back in my truck, found I couldn't push the clutch in and ended up ripping it out again to fix that problem. It's back in now and running fine so now I just need some jobs to pay for the repairs.

I tidied up my shed just enough to move around in, then adjusted the lathe as best I could, although there's still some slop in the carriage gibs that I can't get rid of. It's usable but I'll have to investigate further.

As the new lathe is quite a bit different from my last one, I figured a small project to get the hang of it was in order. So I tried my hand at making my first ever wobbler. Frustratingly, the darned thing refuses to run and I've chucked it under the bench where I can't see it mocking me. In my defence, it is a tiny little 6mm bore x 10mm stroke and was supposed to run on steam. I'll rework it at some latter date.

So back to the engine. I have the fuel check valve mostly done, I just need to bore the holes for the locking pin and find a 1/8" ball and assemble it.

The carby is also nearly finished and ready for assembly, except for the slot in the needle adjuster knob. Brian - if you haven't given up on me and stopped reading my ramblings - what is the purpose of the slot? The only way I can see for me to make it would almost be considered butchery so if it's not vital I may omit it.

I will now make a very bold statement - Sometime this coming week I will be trying to get my engine to start!!!

Til then - thanks for reading.


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## Brian Rupnow (Nov 17, 2013)

Cogsy--I haven't given up on any of my builders. The slot serves only one purpose.--When the engine is running, the needle valve will either try to vibrate one way and unscrew itself, or vibrate the other way and screw itself in farther. The slot lets you squeeze the sides in a little bit and "grip" the threaded part which it screws onto, to keep the needle from vibrating out of position.---Brian


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## Cogsy (Nov 17, 2013)

Thanks Brian. That makes perfect sense. I'll do my best not to botch it.


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## gus (Nov 18, 2013)

All of us are graciously and anxiously waiting for the birth of the H&M baby.

Gus now on holiday with darling boss in South Thailand. No worry .Cheap Air fare and cheap hotels and cheap but good seafood.
Nellie having a great time shopping.


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## Path (Nov 18, 2013)

Nellie having a great time shopping. 	

That may not be cheap!

Have a great time ... looking forward to your return!

Pat H


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## Brian Rupnow (Nov 27, 2013)

Cogsy--What's up Doc?? Any progress??


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## Cogsy (Nov 28, 2013)

Brian - I have a tale of woe but I'll spare you and just say that I jinxed myself and haven't set foot in the shed at all since my last post. However, after tomorrow I have a forced 8 day hiatus that should let me get back to work on my engine. Fingers crossed but lesson well learned - no more promises!


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## gus (Nov 28, 2013)

Cogsy said:


> Brian - I have a tale of woe but I'll spare you and just say that I jinxed myself and haven't set foot in the shed at all since my last post. However, after tomorrow I have a forced 8 day hiatus that should let me get back to work on my engine. Fingers crossed but lesson well learned - no more promises!




Hi Cogsy,

Take it easy. Christmas around the corner.

Gus too struggling with the H&M mechanism.:wall:


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## Brian Rupnow (Dec 15, 2013)

Cogsy--What's happening brother?? This year has almost got away on us. We are still waiting with great anticipation to see the worlds 4th running 'Rupnow Engine". Hope all is well with you.---Brian Rupnow


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## Cogsy (Dec 15, 2013)

I have made progress, slowly, between stupid self-inflicted injuries. Yesterday I got the ignition sorted to the point it will spark when required and now I only have to make a head gasket and assemble the engine. 

Today is forecast to be 41 degrees celsius in the shade, so it will be quite late in the day before I can get into the uninsulated tin shed. I will make it though, and I'll attempt to get it fired up either tonight or tomorrow. 

So, my next post will either be - "It's running!" or "%$^#&*@ - I QUIT!!!!". We'll see...


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## Philjoe5 (Dec 15, 2013)

Too much invested to quit...just keep at it, 'cause that's all it takes.  From someone who's been there

Cheers,
Phil


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## rcfreak177 (Dec 16, 2013)

Cogsy said:


> I have made progress, slowly, between stupid self-inflicted injuries. Yesterday I got the ignition sorted to the point it will spark when required and now I only have to make a head gasket and assemble the engine.
> 
> Today is forecast to be 41 degrees celsius in the shade, so it will be quite late in the day before I can get into the uninsulated tin shed. I will make it though, and I'll attempt to get it fired up either tonight or tomorrow.
> 
> So, my next post will either be - "It's running!" or "%$^#&*@ - I QUIT!!!!". We'll see...



Yes Very hot here in Kelmscott too. measuring 43C or 104.9 degrees farenheight in my yard

Fingers are crossed for you on getting the engine running mate. Can't wait to hear it.
Good luck.

Baz.


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## Brian Rupnow (Dec 16, 2013)

Send some of that heat my way guys. Its -10 F here, colder than a witches tit, with 8" of snow on the ground!!! I've had pneumonia for the last 3 weeks so haven't been doing much of anything in my shop. ---Brian


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## gus (Dec 16, 2013)

Done 39 C in NW India .No fun.The hot Indian Curries helped. 

Done 41 C in Yangzhou,China ,was sick for a few days. Spent my holiday in the hotel room with
aircon at full blast. Done -5 C in Nanjing,was nice and comfortable in Winter Wear.

Give me back good old Singapore, 28-----31 C  with the rain and RH at 85---90.If it gets worse,I can run to the shopping complexes to cool off.


Hi Cogsy. Hang on there and the "worst will be over".Came from Tales of Two Cities.


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## Cogsy (Dec 20, 2013)

So it's still not running, but I'm not quite ready to quit yet.

I did manage to get a couple of pops out of it, but not consistently and then I destroyed my hall sensor with a series of high speed impacts with the trigger magnet. In the car, $20 worth of fuel and $11 for a couple of sensors only to find they either don't suit my ignition or they're just faulty. I've now cobbled together a points setup to trigger the CDI and that seems to be working fine. I'm happier that it doesn't have any advance built in so I can dial the timing in better now.

Now I know I have a small leak on my intake valve and my head gasket material is a little too thick, so there is a small leak there as well. I'm also not convinced my piston rings are 'round' enough. So, the plan is now, in order : Seal the head gasket properly and re-try, if no success make new rings using a different method, if no success make new piston using an O-ring instead, if no success re-lap the valves, if no success build a model boat and use engine as anchor...

So off I go to the shed again.


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## Brian Rupnow (Dec 20, 2013)

Cogsy--Been there--Done that!!! I had hair before I started building model i.c. engines.---Brian


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## gus (Dec 21, 2013)

Hi Cogsy,

You are almost there. A few pops means you are near the finishing line. 

My confession>
Day one. Spent a whole day fiddling around and only get pops.
Day two. Got her running.
Day three .Lost her.

H&M.

I promise will get H&M going after Christmas.
Day four. Got her running smoothly.


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## Swifty (Dec 21, 2013)

Hi Cogsy, 

I would be doing the easy things first before remaking anything. Repair the head gasket, lap the valves, then if it still won't start you will have to work on the rings or modify the piston to take an O ring instead.

When I tried my initial run, I used my battery drill to crank it over. It soon enough started to fire, bedding the valves in that little bit more, it was off and running after that. Just check that the fuel is OK as well, I find that I only need a quarter turn of the needle from fully off in hit and miss mode, if I hold the governor down to stop it working, I get more speed out of the motor when I lean the fuel off a bit more..

Paul.


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## Cogsy (Dec 21, 2013)

Thanks guys. I sealed up the head gasket, which made my intake valve leak worse, and I checked the rings which seem fine. So I lapped, tested, lapped, tested, repeat for quite a while with no joy.  then made a new intake valve with a tighter fit on the shaft, lapped it repeatedly, no joy. Then I had an ah-ha moment when I discovered a very small leak down the side of the intake valve cage (I couldn't fit my head in it so I'm calling it small). Removed the cage, made a new one, installed it, lapped the valve and my compression has improved dramatically, although there is still a small leak on the gosh-darned intake valve!

I can get it to repeatedly fire when I choke it with my finger over the carby and then release, but still no running. I'm going to keep trying this for a while this morning, in the hope that the valve will seat itself, if it doesn't I guess I'll relap the valve, just for a change.

Can anybody point me in the direction of model boat plans??


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## Swifty (Dec 22, 2013)

Cogsy, what are you using for a fuel tank? Is it sealed up not allowing air to get in. I built my tank filler cap with an air bleed screw in it, but I must remember to open the vent screw to allow the fuel to be sucked up, once I was showing someone the engine and it wouldn't run, then realised that the vent screw was shut.

Paul.


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## Brian Rupnow (Dec 22, 2013)

Cogsy--Do as I have repeatedly told others. Put a v-belt sheave on the output shaft, and drive the engine at about 600 rpm with an electric motor. Make sure gas and spark are working and switch is on. Keep it running and play with the carb setting and timing until you get it to start firing more or less consistently. That will seal up any leaking valves. You need a bout a 3:1 ratio on the v-belt sheaves, --i.e. a 2" on the motor and a 6" on the engine (assuming you electric motors over there are +/- 1800 rpm.) 6" pulleys don't generally have a 3/8" bore, so make a split bushing to fit the 6" pulley to the 3/8" engine output shaft. Make sure its turning the right way.---Brian


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## gus (Dec 31, 2013)

I used a hand held starter to spin engine to run and seat the piston rings and valves.

In between,I let the starter to cool down for two hours and spun engine till I could feel good suction and good resistance to TDC. 

The engine gave a few pops and after adjusting fuel jet needle,I did get her started and from there fine tuning of carb. Carb tuning can be evasive and eventually with some patience I got her running. From tune carb. Was good that I had some good experience with the Webster Engine before building the Ropnow H&M.

Hang on there as you are nearly there. Carb/valve timing/igniton timing can be fun and frustrating. Either one will mess up starting.

Happy New Year.


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## Brian Rupnow (Feb 17, 2014)

I take it that the Australian version of the "Rupnow Engine" is now resting on the bottom of a Bilabong??


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## Swifty (Feb 17, 2014)

That would just be the West Australian version, the Victorian version still runs well.

Paul.


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## gus (Feb 18, 2014)

The Singapore Flied Chicken Lice spinning but not hitting and missing yet.

After the Burma Bank Fishing Trip,same engine will be  ''hitting and missing''.

Now busy retrofitting my DIY cheapy deep sea rod holder which the swivel base busted.


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## Cogsy (Jun 19, 2014)

I'm back, admittedley with my tail between my legs for being away so long.

Events have conspired to keep me from engine building, or even viewing the forum for quite a while (I know it sounds like I've been in prison but I haven't, I promise).

So without further ado, I'll bring you up to speed on my Rupnow build, if you're still interested.

With all the pops and bangs I was getting, and the increased compression I could feel, I suspected fuel was my issue. As Swifty suggested, I was lacking a vent hole in my fuel tank, but as it was a thin, flexible platic bottle, I didn't really think that it would be much of an issue. Eventually, I built an intake manifold and adapter to take a model plane carby and put that on, still without making much difference.

I played with the mixture till I was blue in the face and eventually had it firing consistently, but it wouldn't self sustain. Then I lifted the 'fuel tank' above the carby and it took off running perfectly! I was so very happy, for about 60 seconds or so. Then it siezed up solid :wall:. I was mildly upset at this point, but I did refrain from using my 8 pound sledgehammer on everything in sight before I locked the shed and walked away.

When I did get back to the shed a couple of weeks later, I stripped the motor down, everything seemed good, but it appeared the rings had grabbed. All I could think was that I hadn't cut the ring groove in the piston quite deep enough and as the rings expanded they had no room to grow. I chucked the piston in the lathe, deepened the ring grooves slightly and widened them a poofteenth. Reassembled everything and it felt perfect again.

I reinstalled my original carby (made to Brians' plans) and it started and ran no problem at all! Victory at last!

I then made up a fuel tank and bracket , but I do need to revisit it and make a bigger one. 

This is where the story ends though, as circumstances beyond my control took over at this point. I'm back on track now, and I've just ordered my first ever plans and casting kit for an engine. I won't be starting it for a while though, as I still have to finish off my Rupnow engine, including making the hit and miss mechanism for it.

My apologies for such a long break in communication, I'll try and do better in the future. For now, I've got 6 months worth of posts to read so I'd better get started.


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## Brian Rupnow (Jun 19, 2014)

Cogsy---I am so happy to see you back on board, and to hear of your success. Did you get the hit and miss system working? We would love to see a video.---Brian


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## gus (Jun 19, 2014)

Hi Cogsy, 
Congrats.You got it going. 

In about two weeks there should be two Nemett-Lynx Engine about to spin. And at least another two more too.


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## Cogsy (Jun 23, 2014)

Thanks guys. I haven't built the hit and miss mechanism yet, but I will be starting tomorrow, as long as the wife lets me. I will post a video of the running engine, hitting and missing, just as soon as it's done.


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## gus (Jun 23, 2014)

Cogsy said:


> Thanks guys. I haven't built the hit and miss mechanism yet, but I will be starting tomorrow, as long as the wife lets me. I will post a video of the running engine, hitting and missing, just as soon as it's done.




The valve and ignition timing must be spot on. Good indication is easy starting
at every spin start. Engine speed at medium.The governor arm sub-assembly and the trigger lever must be smooth and well oiled. You may have to play around with the main spring. 
Have fun. ( My darling boss thought Gus gone bonkers staring at a crazy engine that just won't run steady for hours!!!)


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## Cogsy (Jul 15, 2014)

Time for a quick update so you don't think I've disappeared into an abyss again.

I built a new fuel tank but haven't made a bracket for it yet, and then tried to start the engine again. Nothing. For 2 days. It would pop now and then but refused to run. I played with ignition timing and reset the valve timing. Actually, I don't remember Brian recommending anything on valve timing. Maybe I missed it but I've just used my best estimate. Then I adjusted the fuel needle 7.2 million times. Then I changed back to the RC carby and fiddled with the needle a further 6 million times. Pops, sometimes a couple in a row, but no running.

Eventually, I removed the spark plug and checked spark, even though I knew it was sparking from the random pops. No problem there, turning the crank by hand I had a big, fat blue spark. Then, as I had no compression with the plug out, a quick spin of the crank showed - No spark  . Turn the crank slowly and there was good spark. Turn it fast and nothing . Spin it with a drill and there was the odd random spark (hence the random pops) . I'm using a CDI ignition that's supposed to be triggered by a hall sensor, but I've changed it to points as I killed all my sensors. I figured I'd killed the unit somehow, but it turned out... drum roll here...the 4 AA batteries that power the CDI were flat :wall:. Changed them, VROOM, instantly. Oops.

So since then I've been having greater success. The governor stem post assembly is complete. Now I need to work on the bracket and the shaft, spring adjuster and latch. Hit and miss day is approaching slowly.


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## Swifty (Jul 15, 2014)

Hi Cogsy, glad to see that you got that problem sorted.

Paul.


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## Cogsy (Jul 15, 2014)

Thanks Paul. I can't believe how long it took me to find out I had flat batteries. Lesson learned though, from now on I'll double check all the easy things before I start searching for gremlins.

Progress might speed up a bit soon - I think I'm about to find myself 'between jobs' for a while.


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## Path (Jul 15, 2014)

Hey Cogsy ..

Great update ...

Fat blue spark   who would of thought batteries  .. not me, but now we
know!  Thanks.


Pat H


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## Brian Rupnow (Jul 15, 2014)

Cogsy--Don't feel too bad. I can not count the number of times that I have been tuning an engine, when suddenly it would trail off and quit for no reason. After checking about a dozen things that could have potentially gone wrong, I discover that it has run out of fuel!!!---Brian


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## gus (Jul 15, 2014)

Wish You All Success to the H&M happening!!!

Now busy upgrading the RT to get rid of excessive back lash which cause chattering when profile milling Con-rod big/small ends. Just graduated the hand dial. Cam cutting for the Nemett-Lynx Engine begins soon as the engraving cutters arrive.


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## gus (Jul 16, 2014)

Will soon be Gus's turn to mess around with the electronic CDI. 
Hopefully the CDI won't get fried. Can't make ''Fly Lice'' aka Fried Rice.


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## Brian Rupnow (Jul 16, 2014)

Gus--Whatever you do, don't trigger the Hall effect sensor without a well grounded sparkplug in the circuit. That is what fries them.---Brian


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## gus (Jul 17, 2014)

Brian Rupnow said:


> Gus--Whatever you do, don't trigger the Hall effect sensor without a well grounded sparkplug in the circuit. That is what fries them.---Brian




Will connect earth first. Is this battery  +ve or -ve?

Thanks.


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## Brian Rupnow (Jul 17, 2014)

Gus--I believe they are negative ground, but I am certainly no expert. You will have to ask whoever you purchase the ignition components from. I know my way around ignition points and coils very well, but not CDI ignitions. I am sure of what I said in regards to not firing the ignition without a well grounded sparkplug though.---Brian


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## SixSixSevenSeven (Jul 18, 2014)

positive earth is very rare. Almost all electronic components are negative ground (earth isn't a phrasing used so often in electronics although the 2 can be interchanged). Of course as always check the documents beforehand to confirm, but it should be earth/ground on negative.

In theory, hall sensor triggering without a grounded sparkplug shouldnt do anything odd, I can only assume the hall sensor itself was not properly grounded. Still, might aswell ground it anyway, better safe than sorry


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## Cogsy (Jul 21, 2014)

So I've been slogging along making parts and it's been going pretty well. I somehow managed to manually resharpen a broken 1.5mm drill bit, even though I couldn't actually see the cutting edges. Then I turned the smallest part I've ever made - a locking pin with a .057" diameter shaft. I don't know about anyone else, but for me, that's a small part.

Here's a pic of my completed governor shaft. It was fun to make and my wife and daughters are very impressed with the movement of the weights and shaft.








Here's a shot of the 57 thou pin I was talking about. I didn't say it was pretty, just that it was small.









I'll end this post now to save it becoming a long one. More to follow very soon.


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## Cogsy (Jul 21, 2014)

At this point I had to disassemble the engine just to drill and tap the mounting holes for the governor mechanism. I hate to pull apart a running engine but it had to be done. I drilled and tapped the holes without drama and managed to get it all back together again.

To try and start it, I decided to go with the RC carb, just so I could be reasonably certain the carb would work properly (nothing against Brians' design, it's my building skills I don't trust). For ignition I have a Chinese CDI coupled up to a set of automotive points. It works, but timing is challenging and ends up being a lot of trial and error. I will be changing to a different ignition at some point but I haven't decided what sort yet.

Valve timing was set by guessing and hoping, but I doubt it's too far off.

I was able to test the governor mechanism by spinning the engine over with my electric drill and it worked just as well as I hoped it would.

1/2 an hour of spinning it over, tinkering with the carb needle and resetting the timing had the engine making all sorts of promising noises and then ---- it started up! Then promptly started missing...then firing...then missing... and so on. It still needs a lot of tinkering with the carb (I'll change to the one I made before long), ignition timing, valve timing and governor settings, as well as a fair amount of breaking in, but I'm over the moon it's running.

Once it's all sorted I'll strip it down again and clean and polish it all up, then it's mount to some sort of base and present to my father as a long overdue gift.

Below is a low quality video, but before you watch it there are some things I need to point out. 1. Yes, my work bench is atrocious. 2. Yes, the engine is filthy. 3. Yes, I filmed the clip with a potato, in the dark. and 4. Most of the fasteners you can see will be replaced with the correct size and style before the engine is finished, I just cobbled together what I had to get it going.

Also, just FYI, when I reach over the engine I'm adjusting the governor spring tension, not the carb.

Enjoy!

[ame]https://www.youtube.com/watch?v=jpeieS9NJvE[/ame]

Thanks for looking.


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## Swifty (Jul 21, 2014)

Great job Cogsy, the sound of it running is certainly familiar.

Paul.


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## Cogsy (Jul 21, 2014)

Thanks Paul. Yep, those miter gears are noisy little things aren't they. In the flesh the exhaust note stands up a little better though.


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## Brian Rupnow (Jul 21, 2014)

CONGRATULATIONS!!!! You are now a member of a very select club. I think that is "Rupnow Engine" #5 to come on stream around the world, (I think)  but I am losing track. there is mine, Swifty's, Gus's, and yours. I think I may have missed someone, but I can't remember who.---Brian


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## Cogsy (Jul 21, 2014)

Thanks Brian. I will make it prettier than it currently is, but it sure is a nice feeling having it running. I hope I don't wear it out before I give it away, but I've got a feeling I'm gonna be burning quite a bit of fuel in the next week or two.


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## gus (Jul 21, 2014)

Hi Cogsy,

I like the H&M Chimes of your engine which sounds sweet.th_wav


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## Cogsy (Jul 21, 2014)

Thanks Gus. It's been a long time coming, but you're right, it sounds good.


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## Brian Rupnow (Jul 21, 2014)

Cogsy--I have watched the video a few times now. Your (ahem) balls--should be moving up and down a lot more. This may require a bit of fettling on the levers which the balls are attached to, where they contact the top of the central rod, or it might be a matter of adjusting the length of the rod itself.The total movement between when the balls and arms are hanging almost straight down and the time when they have flow out fully under centrifugal force has a very great bearing on the number of miss cycles the engine goes through before it hits again.---Brian


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## Cogsy (Jul 22, 2014)

I noticed that I wasn't getting much ball action either (I almost couldn't type that sentence ;D), and I will investigate it. I understand how the mechanism works, of course, but I can't get my head around how to optimise it.

Mine seems to be running almost in equilibrium where a very slight increase in engine RPM allows the balls to lift slightly, engaging the latch and making the engine miss, which then drops a few rpm, instantly disengaging the latch before the balls have a chance to sink much. This means I don't get many misses per cycle and not a lot of variation in engine RPM either. I know there is a lot more travel to be had for the balls to sink lower and raise higher. Everything is free and smooth.

One thing I have done is set up the latch so it doesn't quite hold the exhaust valve at full open, so the cam has a slight action on the pushrod each 'miss' revolution. I set it up like that so the latch couldn't jam in place and cause the engine to stall. I wonder if it needs a slight 'jam' so engine RPM can fluctuate more.

The first thing I'll try is to adjust the latch so that it engages when the balls are at the top of their travel. Maybe I missing some sort of variable force dependant on ball angle. Ok, I'm going to have to change to using the term 'weights'. The schoolboy in me keeps chuckling...

Anyway, I'll have fun testing theories and let you know how it works out.


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## Cogsy (Jul 22, 2014)

I have more ball movement now. I adjusted the latch so that the balls fly out to nearly their maximum before it catches and that has made all the difference. Thinking about it in my study while reading a technical journal (ok, on the dunny playing Angry Birds on my iphone), I do remember high school physics and something about "conservation of momentum". If I remember correctly, when the balls are all the way out, for them to be drawn back in they need to spin faster to conserve their momentum. In reality or course, the mechanism slows them down but I believe they come down at a slower rate that they flew out, while trying to "conserve momentum". This gives the change in engine RPM. Anyway, even if I'm way off track, adjusting them has worked for me. 

I tweaked the ignition timing a tad and I'm reasonably happy that's it pretty close now. I also changed out the spring on the governor adjuster as it was a smidge too soft and I managed to get coil bind at one point, sending the engine way over-revving.

I also changed out the carb to the one I built from Brians' design (the big bore one). Screwed the needle all the way in, then adjusted it out as I spun it over. It was running inside of 10 seconds. The new carb is a heck of a lot better to tune than the RC carb. Must be the fine taper on the needle but it's easy to get it tuned just right.

So with everything set, I let it go for it's first long run. I had to leave the shed for most of it, out of fear of CO poisoning (it's raining here today so I couldn't leave the big doors open). I shut it down after 15-20 minutes of trouble free running.

I am running into one potential problem with the engine though - I'm already foreseeing great difficulty giving it away to a new owner. Maybe I'll give it to him but tell him it needs to stay at my place...


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## tms6401 (Jul 22, 2014)

Well Done Cogsy ... The engine sounded good ... oh ya ... my bench is worse than yours!

TMS


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## Brian Rupnow (Jul 22, 2014)

Cogsy--Sometimes it will bend your head a bit, trying to envision all of the sequences that happen in a hit and miss engine, and the effect that a small change to one of the components will have on all the rest.--Especially around the governor.-Brian


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## Cogsy (Aug 5, 2014)

I have officially finished the Rupnow Engine! (sort of). In the end I decided not to polish it up, or paint it, but to largely leave it 'as machined'. I realise some people might not like this approach, but as it is a gift for my Dad, I wanted it to be 'approachable' - something he would feel OK about pulling apart and tinkering with and not worry about scratching it. I also wanted to convey some of the work that went into it and to show it's 'home made-ness'. Anyway, for better or worse, that's how he's getting it tomorrow.

I did make a rough base for it (I really don't get along with wood very well) and trim the fasteners, install pins, etc. Once it was all back together, it took hours to get running again. Getting the valve timing, ignition timing and carb settings to gel at the right time was almost as difficult as the first time. I did have it running better than it is now (before I pulled it apart), with a lot longer 'miss' cycles and more movement of the governor balls. The good thing is, I'm giving it to Dad tomorrow and staying at his place for a couple of days, so I'm sure we'll have lots of fun tweaking and tuning it until it runs perfectly again. Soon, I hope to get him to move off the farm and near me in the city (he is nearly 80) and I hope we can build something together for the engine to run.

Many thanks to Brian Rupnow for his excellent design and invaluable help, as well as the other guys who built this engine, and to all the members I've learned from Thm:Thm:.

Here's the final video of it taking me for a walk. 

[ame]https://www.youtube.com/watch?v=MbaHs_UZiFc[/ame]


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## Brian Rupnow (Aug 5, 2014)

Cogsy--A wonderful job, well executed. Thank you for finishing it, and I hope your father really enjoys it.---Brian


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## Path (Aug 5, 2014)

Fantastic job ... glad I followed along.

Your dad will surely love it. 

Great job.

Pat H.


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## Swifty (Aug 5, 2014)

Great job Cogsy, I hope that your father gets many hours of enjoyment from it.

Paul.


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## AussieJimG (Aug 6, 2014)

Good one Cogsy, and it looks great just as it is.

Jim


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## gus (Aug 6, 2014)

Hi Cogsy,

Congrats. You done a great job. The Rupnow H&M Engine is not an easy engine to build and complete and getting the Hit & Miss going was very tough. I nearly gave up if not for the help,support from Brian and Paul and others.th_wav Think of it .Not too many in the world has built this engine. We are the chosen few.Ha Ha.
 No worries about the carpentry,Gus is not good at it either.


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