# Rupnow Ovehead Cam Air Cooled



## Brian Rupnow (Jan 25, 2017)

This morning I'm setting around with some free time, and I've been thinking for a while now about an overhead cam air cooled engine. There are a lot of horizontal and vertical cylinder engines out there, but I haven't seen very many single cylinder engines like the old "Iron Horse" washing machine engines with the cylinder on a 45 degree angle. My thoughts of course, were that if you could hang the entire camshaft off the cylinder head, then it would give you the freedom to run the cylinder on just about any angle you wanted. By using a cogged belt drive to the camshaft instead of a gear train, that opens up even more freedom with placement of components. I looked through all of the engines I have built over the past few years, and ended up leaning heavily on my Atkinson for some of this, so if it looks a bit familiar, then that is why. I'm not saying I'll actually build this, but you know how it is------Brian


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## Ghosty (Jan 25, 2017)

Brian,
Just waiting for you to start the build

Cheers
Andrew


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## Brian Rupnow (Jan 25, 2017)

Well----At this point in time it looks Ahhh---Interesting!! I've been waiting most of the day for a call back from a customer, and while I wait I can "doodle". As shown, it has a 1" bore, a 1 1/8" stroke, and that is a 5 1/8" flywheel setting on there. The crankshaft is 3/8" and runs on two sealed ball bearings at each end. The crankshaft is a two piece unit. The "driver" end which supports the flywheel and has the rod journal  on it is one pressed together assembly, the other part of the crank is a "follower crank" and will ultimately drive a cogged pulley and the ignition points. The cogged pulley shown on the cam shaft is only about half the diameter it will end up being in reality.--There may even be a way to incorporate fan blades into the camshaft pulley to blow a stream of cooling air over the cylinder.


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## Brian Rupnow (Jan 25, 2017)

The only bearings that will need lubrication in the engine itself are the con rod big end and the wrist pin. The con rod big end is very easily accessible for a squirt of lubricating oil from my trusty oil can. The wrist pin, however, is hard to get at to oil. Since this is a 1" diameter piston, I am going to try and find room in the small end of the connecting rod for a sealed ball bearing. I won't do that at the big end because it throws the crankshaft too out of balance.


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## Brian Rupnow (Jan 26, 2017)

I was able to shorten up the blue towers considerably, by getting rid of the pellet shaped pushrods completely and letting the cams push right on the end of the hardened yellow caps. These yellow caps are closed on the end that contacts the cap, and open on the other end to contain the valve spring and for a pinned connection to the end of the valves. The transparent bar guides them and keeps the cam from putting any side load on the valve stem. I thought about how to tie the two sideplates together and decided that a piece of 3/8" thick aluminum angle would be just the ticket. It provides rigidity to the sideplates, and also acts as a great containment for any oil slung off the big end of the con rod. I will mill a recess for a polished brass cover plate which has super magnets embedded into the underside of it, and put some ferrous plugs in the aluminum side plates for the magnets to stick to. this allows me to remove the cover plate, give the big end of the rod a squirt of lubricating oil, then put the cover plate back into place. I am not a fan of oil filled crank cases.


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## Herbiev (Jan 26, 2017)

Looks like a great project for this coming winter. Just waiting on a new set of contact points to arrive for the Rupnow Vertical and if all goes well I'll be ready for another project.


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## Brian Rupnow (Jan 27, 2017)

So---The plot thickens---a little bit. I see that with an adapter, I can mount one of my Traxxas carburetors. I could build my own carburetor, but why make more work? I hunted around on my old Atkinson engine thread from back in 2012 and found the name of the company I bought the timing belt and pulleys from. This time I need two pulleys, one exactly twice as big as the other for my 2:1 ratio, and since I now know what my center to center of pulleys are, I was able to call the company in North Carolina that supplied the pulleys 5 years ago and ask for price, delivery, and 3D solid models of the pulleys. I added an exhaust "muffler" and manifold to the engine. (I may rethink the shape of that exhaust manifold, I'm not sure yet). It doesn't show in the model, but I have rejigged those magenta coloured bearing housings to set in tighter to the engine sideplates. The timing belt pulleys on the engine are not updated yet.--I have to get the new 3d models before I can do that.


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## Brian Rupnow (Jan 27, 2017)

I was wondering about where to put the ignition points. Once again the beauty of a single cylinder engine being able to run a "waste spark" system has saved me. I can fit them on the side opposite to the flywheel and run them off the crankshaft. Although the top timing belt pulley up at the cam is going to be twice as large as the diameter shown, the small pulley down at the crankshaft is going to stay very close to what is currently shown.


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## Brian Rupnow (Jan 27, 2017)

Admiral_dk--as per your suggestion, I have swapped the position of the exhaust pipe and the carburetor. I don't know yet if I will leave that strange little intake manifold in place, or remove it completely and let the carb stick out at 90 degrees from the cylinder. That might look good with a really well shaped air intake horn.


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## Hopper (Jan 27, 2017)

I like the idea of the guide block for the cam followers. Otherwise the tall valve stems might end up putting a lot of sideways strain on the valve guides due to cam wiping action. Or could you not make the valve springs and stems shorter and the follower the shape of an upturned bucket that sits down over the springs to make it more compact? Probably would still need the guide block though.? Seems that is the way they do it on the DOHC Honda motorcycle engines I work on sometimes and I have always been very impressed with the way Honda do things.


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## Brian Rupnow (Jan 28, 2017)

I had to move the cylinder intake port around again, as there was no way to get a gas tank mounted with the previous configuration. This will work out pretty good, I think. The exhaust pipe discharges out between the timing belt drive, and the carburetor sucks in fresh air from the flywheel side. I had to make my "crank-case access hatch" a bit smaller as the gas tank covered the top portion of it, but I still have lots of room to get in there with a squirt can. I am going to have to rethink  the use of a ball bearing in the small end of the con rod. A 3/16" i.d. ball bearing is 1/2" o.d. and there simply isn't enough room for it.--And nobody sells a 3/16" sealed roller bearing.


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## canadianhorsepower (Jan 28, 2017)

Brian 
go to hobby shop they use that size on RC boat


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## Brian Rupnow (Jan 28, 2017)

Thanks Luc, I will check that out locally.---Brian


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## Brian Rupnow (Jan 28, 2017)

A big THANK YOU shout out to Luc from Quebec for putting me onto R.C. ball bearings at the hobby shop. I bought two 3/16" i.d. sealed bearings that measure 0.311" outside diameter x exactly 0.125" thick. These two will set side by side in the small end of my 1/4" thick connecting rod. They are part #DTXC1413, and cost $2.49 each. Yes, I do realize that ball bearings are not recommended for something like a wrist pin, which only oscillates back and forth, but doesn't spin fully around. However, they have to be better than a bushing with no lubrication at all. Time will tell about that one.  I also bought four 1/4" sealed flanged ball bearings that are 0.421" diameter over the flange, 0.375" over the other diameter, and have a total thickness of 0.125". Each camshaft support tower will receive two of those. They are part #DTXC1517 and cost $3.99 each. This means that the only bearing surface on this entire engine that doesn't have a ball bearing will be the big end of the con-rod, which will probably get an oilite sintered bronze bushing, and will be easily accessible for oiling by removing the magnetic "inspection hatch" cover.


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## Brian Rupnow (Jan 29, 2017)

I keep moving things around, looking for the "ideal" configuration. I got my information today on that 60 tooth pulley that goes on the cam shaft, and it's big enough in diameter that my exhaust pipe was going to run thru the side of it. I messed around a bit having the exhaust come out of the cylinder and point straight up, but that not only looked a bit dumb, but would have covered the entire engine in oil spatter after five minutes of running. Then I had a new thought and turned the cylinder head around 180 degrees on the cylinder. I like that!! I can still have the carburetor where it was before, and have the exhaust pipe pointing down and away from everything.


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## Cogsy (Jan 29, 2017)

That is a massive pulley on the top end - do you really need 30:60 teeth or maybe something smaller like 15:30 or 20:40?


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## Brian Rupnow (Jan 30, 2017)

There are things going on down at the bottom pulley that preclude making it smaller. That top pulley may very well get modified to have a fan incorporated into it.


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## Brian Rupnow (Jan 31, 2017)

Why yes, I DO have a rotary table!!!--And sometimes I do use it for making something other than gears. I have turned the crank on this one so many times this morning that I'm thinking of changing my name to "Crankenstein". If I don't manage to screw this up before I get finished, it is going to make a very pretty little cylinder head.


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## Brian Rupnow (Jan 31, 2017)

When I first looked at the cylinder head detail, I immediately had a big whine and thought "Oh, but this is going to be so hard.---Wahhhhh". Then I thought "Yes, but I've designed similar "hard to make" parts over the last fifty years, and never gave a second thought for the poor guy in the machine shop who actually had to build the parts. So, since I liked the design, I went ahead and made it to the drawing. Lots of work and multiple set-ups there, but I like the finished part. And every part like this that I make stretches my abilities just that little bit more.---I did change the timing belt pulleys.--went from 30 tooth and 60 tooth down to 20 tooth and 40 tooth. Proportions look a lot better now.


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## Brian Rupnow (Feb 1, 2017)

It's a whole new world running a lathe with a DRO on it. First observation is that no matter how well placed the display unit is, you can't watch both it and the tool tip at the same time. You can watch one, or you can watch the other, but there is no way in Hell to watch both at the same time. When the lathe is in "power feed" mode, those numbers change awfully quick. The first pass isn't too bad, because there is no shoulder on the part being turned. By the time you get to the third pass, there is a pretty good shoulder formed on the part, so you definitely don't want to over-travel. Working with a DRO is a lot like that old-time religion.--You just got to have faith!!! That is a piece of grey cast iron in the chuck, and I'm taking 0.020" depth of cut at about 260 rpm. with a brazed carbide tool. The o.d. on that cast iron is crusty, rusty, and kind of horrible. I chuck it up in my lathe semi-tight, then use my "bump tool" to bring it to as close as I can get it to running true, then tighten the chuck up all the way. the material is larger than the bore in my spindle, so I put a center countersink in the non chuck end and then run a dead center in my tailstock chuck to assure that it doesn't come bounding out of the chuck and chase me around the room. I had that happen once, and it is a life altering event!! I leave the lathe in "power feed" until I see the last 0.100 of travel come up on the display, then kick out the power feed and finish the travel with the big wheel on the front of the apron.


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## stevehuckss396 (Feb 1, 2017)

Sorry brian but when i read the first sentence I had to laugh.

Suggestion 1 - Mount your readout on the wall left enough of the chuck so coolant wont splash on it and swarf wont get flung on it. This way you can switch your eyes back and fourth between the chuck and display without even moving your head. It's a bit more comfortable than having to turn your head to the left all the time.

Suggestion 2 - When you power feed watch the DRO on the first pass to get the shoulder located. Then power feed watching the part and run right up just short of the shoulder and undo the power feed lever. Then look at the DRO and finish up the last bit. With a little practice you will be able to stop .010 short of the shoulder and then just bump in by hand. This way you are never power feeding without looking at the actual tool bit.

Once you get used to it, you will never want to be without the darn thing.


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## Brian Rupnow (Feb 1, 2017)

It's okay Steve---I've been laughed at for far lesser things. I like the DRO. It's just a "new thing" that I haven't done before.---Brian


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## Journeyman (Feb 2, 2017)

Hi Brian
Neat engine design, looking forward to the build. With the DRO it might be worth investing in one of those soft plastic covers for the readout, keep the oil and crud off and when you can't see through it just replace it
Cheers John


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## Brian Rupnow (Feb 2, 2017)

John--that display comes with a clear plastic adhesive sheet on the front of it that can be pulled off and replaced when it gets too dirty.---Brian


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## Brian Rupnow (Feb 2, 2017)

This morning we have a cylinder. The fins are all the same width, and trust me, ---that's a good thing!!! I have a tailstock live center that is just barely large enough to act as a bull nose to prevent the outboard end of the cylinder from moving under the side pressure of cutting the fins. I always drill the center bore out before cutting fins. Start with a 3/8" drill and move up by 1/16" increments until I get to 15/16", then drill thru with a 31/32" drill, then ream to 1" finished bore. I cut the grooves between fins .094" wide x 0.345" deep using a 3/32" HSS parting off blade and the lands between grooves are .094" wide. The lathe was turning at 230 rpm. and I cut the fins almost full depth with automatic feed, except for the last .025" which I fed by hand, so as not to overshoot. Although it made a Hell of a racket it got the job done right smartly.


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## Journeyman (Feb 2, 2017)

Brian Rupnow said:


> John--that display comes with a clear plastic adhesive sheet on the front of it that can be pulled off and replaced when it gets too dirty.---Brian


Ah! Didn't realise that, the wonders of modern technology...
John


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## Brian Rupnow (Feb 2, 2017)

I have a question, and it's a hard one. Fortunately, I also have the answer to the question. On a cylinder like the one in the drawing, after you have tapped the four holes in one end, how the heck do you turn it around and put the tapped holes in the other end in the same rotational orientation? This is almost impossible to do.-------Unless-----You have a rectangular plate that bolts onto the other end. If you do, you make the rectangular plate, bolt it onto the first set of holes in the cylinder, then hold the plate in the vice so you can tap the holes in the other end of the cylinder, with assurance that the second set of holes really will be aligned rotationally with the first set of holes!!


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## RonGinger (Feb 2, 2017)

Or a clever designer could make the part with a square flange at one end.


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## Brian Rupnow (Feb 2, 2017)

News is not good. The company in North Carolina that sold me timing belts and pulleys 5 years ago mailed them to me. Now they say they can no longer mail things to Canada, and that they want a $50 courier fee for $25 worth of parts.---plus tax---plus customs fee---plus difference in Canadian and USA dollars. I was ready to eat the difference in Canadian/American dollars, but this is a bit too much like robbery for my taste. I'm now trying to source the pulleys and belt from a Canadian supplier.


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## Brian Rupnow (Feb 2, 2017)

RonGinger said:


> Or a clever designer could make the part with a square flange at one end.


True, but--My local supplier only carries cast iron up to 2 3/8" diameter, and only in rounds.


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## Brian Rupnow (Feb 2, 2017)

I think I'm going to have to do something to keep those yellow "lifters" from rotating. Ordinarily, you would want them to rotate a bit each time the cam lobe "wiped' across the top of them to equalize any long term wear pattern. In this case however, if they rotated it would make the valve rotate----and we don't want that. Valves like to settle into one spot and stay there, and that is where they will "wear in" a seating position and seal tighter than a ducks butt. If they rotate a bit with every "wipe" of the cam lobe, then they are going to not seal consistently and will probably quickly wear away the valve seat area on the valve cage.


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## Brian Rupnow (Feb 3, 2017)

After an extensive internet search, I find that there is a lot of contradictory information as to whether or not valves should or shouldn't rotate in an internal combustion engine. Some say no, they shouldn't rotate at all. Some say, yes, they should be forced to rotate fractionally with every cycle to even out wear on the seat. Some say they should not be restrained and allowed to rotate if they "want to". I am in agreement with the "not rotate at all" crowd. I have revamped my design a little bit up at the top of the valves, primarily to keep the yellow "lifters" from exerting any "torque" to the valves through tight clearances. They will still contact the very end of the valve stem, and it's possible that they might try and impart some turning force on the stem thru that end contact, but I'm willing to take a chance and find out. There is a world of design in that tiny area at the top of the valves.


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## Brian Rupnow (Feb 3, 2017)

I have never given this business of rotating valves a lot of thought. There is really nothing on my engines that encourages the valves to rotate.---Then again, there is nothing to stop them from rotating. True, we lap the valves into the seats by rotating them with some compound. However, once the engine starts to run, it actually does "pound the valves down into the seats" every time the cylinder fires. That is why valves seal so much better after the engine has been running for the first 5 or 10 minutes. I do agree that a slight angle or crown on the end of the valve stem will help to prevent any torque from the end of the lifter being transferred to the valve stem.---Brian


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## Brian Rupnow (Feb 3, 2017)

After much phoning around and hair pulling, I found a company in USA that would mail parts to Canada rather than ship via courier. This is much more economical, but there is a catch. Their pulleys and belts at $46 American look the same as the other companies parts which were $17 American. So, being grateful that God made me rich instead of good looking, I ordered them anyways.
http://sdp-si.com/


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## stevehuckss396 (Feb 3, 2017)

I have never heard of valves rotating. Lifters yes but valves no. To be honest I dont think it matters either way as ling as they seal up.


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## Brian Rupnow (Feb 3, 2017)

I had some visitors drop by this afternoon while I was running my milling machine. My machine shop window looks out into our back yard, and these guys all marched right by about 2 foot outside the window. There were 18 wild turkeys, who troop over to my backyard once a day to check out what has fallen from my bird feeder. Of course, by the time I shut down the mill and hunted up my camera, the parade past my window was finished, but I did get one close up, and some of the rest as they were marching back into the woods. What a treat!! My goodness, they are big birds!!


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## Brian Rupnow (Feb 4, 2017)

And here we have the great horned beast of legend---Well, not really, but those cylinder towers certainly give things a different flavour!! The flanged ball bearings are a nice snug fit into 3/8" reamed holes in the towers, and have a 1/4" I.D. for the cam shaft to ride in.


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## Brian Rupnow (Feb 4, 2017)

We have valve cages, all finished and installed except for the seat area which will get done later, and the hole thru the side from intake and exhaust, which will be drilled thru both the cylinder head and the valve cage after the 620 Loctite they are coated with sets up for 24 hours. One was a fairly easy press into place with my two ton arbor press. The other was a harder press, and made it all the way home except for the last .035", which simply wasn't going to go in any farther. This was cause to get out my 5 pound hammer, a piece of brass to use for a drift, and a step over to my anvil. Two good whacks, and it went all the way home. Maybe if I machine things for another 20 years I'll get this press fit business sorted out.


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## Brian Rupnow (Feb 5, 2017)

I guess the question now is "What do I do next." I realized when I designed this engine and valve train that there is no allowance in the design for adjusting the valve lash. That's okay on a "one of" engine, it just takes a bit more time. The secret to adjustment is all in the yellow "lifters". They must be made to a very precise length.---Actually it is a case of making them a length to suit everything else. So, I make the cams and install them on the shaft. I make the valves, lap them, and install them in the cylinder head. Then, making certain that the valves are seated properly in their cages, I measure the distance from the end of the valve stem to the "low" side of the cam. This resultant measurement will give the length from the inside bottom of the lifter which bears against the end of the valve stem to the face of the cam. Then I take about 0.006" from that measurement and subtract it from what I measured to give the appropriate amount of valve lash, and make the lifter to that exact length. This is more work than just turning a screw to set the valve lash, but it allows me to use relatively short "towers" above the cylinder head.


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## Brian Rupnow (Feb 5, 2017)

After what seemed like a lot of time today I have managed to make cam #1. It is made from 01 drill rod, and after the set screw holes are tapped into the hub, it will be flame hardened. I made it the way I had outlined in my thread "An easy way to make a cam" but this time I ran the mill in it's conventional direction instead of reverse. Of course this meant that I had to spend an unconscionably long time finding a boring bar that would fit in my boring head, and grind up a cutter from HSS to work for this application. Since this method has the cutter turned to cut from the outside in, none of my brazed carbide tools would work. I spent longer trying to get a cutter and holder sorted out than it took to cut the cam. The cam isn't 100% because of cutter deflection, etcetera, but it's damned close. I will use it and if it works, great. If it doesn't work properly, I will make another.---Life was a lot simpler before people told me that cutting a cam with the mill running in reverse might unscrew the shank of my boring head!!


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## mjonkman (Feb 7, 2017)

Did you consider machining your own pulleys? vs buying them. I would think them to be far easier to machine then say a gear.  Depending on the belt, some have rounded drive "cogs" that would seem might match a ball nose end mill. For square drive perhaps a slightly modified end mill might work (if it needs a slight taper on the drive cogs). I'm probably not making much sense. Myfordboy on YouTube had an example of making a similar pulley (or set of pulleys). Might be able to find cheap timing type belt on Amazon or an industrial supplier like say McMaster Caar. I've heard that McMaster does ship to Canada and I've heard otherwise but on their site, help section they seemed to indicated shipping to US and most of Canada so it might be worth double checking.


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## Brian Rupnow (Feb 7, 2017)

You can call me Two-cam-Sam!! There are a few things going on in this picture. The cam I machined yesterday just wasn't going to do it. I used the cobbled together boring tool on the left in my boring head to make yesterdays cam, and due to the long skinny shank it deflected enough that the cam surfaces were all slightly tapered. ------So, I made a new heavier, shorter boring tool with a newly ground HSS cutter in it, and made two new cams today. No deflection, and the new cams came out very accurately with no visible taper on the outer diameter. And yes people, the boring head would have unscrewed from the shank if I had been running the mill in reverse. The cams I had made prior to this, using the "boring head method" were mainly from brass, and presented no real challenge to the boring tool. These guys however, are made from 01 drill rod, and it was definitely a "thumping old time" cutting them. I'm glad that someone pointed out the error of my ways, and that I didn't suffer a catastrophe with the boring head coming unscrewed.


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## Brian Rupnow (Feb 7, 2017)

mjonkman said:


> Did you consider machining your own pulleys? vs buying them. I would think them to be far easier to machine then say a gear.  Depending on the belt, some have rounded drive "cogs" that would seem might match a ball nose end mill. For square drive perhaps a slightly modified end mill might work (if it needs a slight taper on the drive cogs). I'm probably not making much sense. Myfordboy on YouTube had an example of making a similar pulley (or set of pulleys). Might be able to find cheap timing type belt on Amazon or an industrial supplier like say McMaster Caar. I've heard that McMaster does ship to Canada and I've heard otherwise but on their site, help section they seemed to indicated shipping to US and most of Canada so it might be worth double checking.


   Mark--I did consider it, albeit briefly. The cuts would require a specially ground milling cutter, or massive screwing around tilting either the head of the mill or the base of the rotary table to give the included angle called for in the slots on this type of pulley. I was just p.off about the people who sell these pulleys in the USA but wouldn't mail them to Canada. I found another company in the USA who will mail them to Canada, so I ordered from them.  McMaster Carr will ship to Canada IF you had a pre-existing account with them before their rules changed about 5 years ago, but they will not open any new accounts in Canada.---Brian


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## Brian Rupnow (Feb 8, 2017)

This is a rare picture of a valve being born!! I turn the small diameter down in three 1/2" long stages, aiming for about .002" larger in diameter than the targeted 0.125". This avoids the issues with deflection that would come up if you tried to turn the entire 1.5" length all at once. Then, using the cylinder head with the valve cages reamed to size as a "try it and see if it fits" guide, I remove the remaining material with 220 grit garnet cloth strips as the lathe is running. When the valve shank just fits into the valve cage reamed hole for it's full length, that part is finished. I set the topslide over to give me a 92 degree included angle on the valve, and then very carefully cut the valve face. I will now cut off the valve from the parent stock with about 2" of the parent stock remaining, which gives me a "handle" to hold and spin by hand while I lap the valve into the seat in the valve cage. The valve stem is unusually long because of the type of engine it is going to be used in, but 2/3 of that length will be guided, so I'm not real concerned about it bending. the valve is made from common 1018 steel.


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## Brian Rupnow (Feb 8, 2017)

Both valves are machined, lapped into their seats, and cut to length. I machined a piece of bronze for the bridge that the "lifters" slide in, although I haven't cut it to length nor tapered the sides yet to match the cam towers. I bought a big box of assorted springs at a hardware store two weeks ago, and have found what I think should be a good spring (it's setting on one of the valve stems in the picture). The spring is 0.215" outside diameter x 0.020" diameter wire. I think I will buy a 7/32" (0.219") endmill and put a .050" deep pocket in the top of each valve cage to keep the spring centered. I will probably modify the "spring keeper" that is pinned to the end of each valve stem to keep them centered at the top end as well. When I rotate the cams thru 360 degrees, they clear the top of the bronze, which is great.--That's the way I planned it, but it it's always nice to have your design confirmed in metal. Tomorrow I have to go down to western Ontario to present a new proprietary automation design to a customer, so I may not get back to the engine until Saturday.


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## Brian Rupnow (Feb 9, 2017)

It's been a busy day!! I got up early this morning and mushed my Huskies down to Ingersoll, Ontario for a design review of a project I have been working on. Had a 1 hour meeting with a bunch of "suits" and then turned around and drove home. I'm getting too old for this s$%t but find it hard to turn down the money. When I got home I made the "keepers" that hold the springs on the valves, cross drilled the keepers and the valve stems with a 1 mm drill (You can see the 1 mm drills in there as temporary "pins). I machined pockets into the tops of the valve cages to act as "locators" for the springs, and assembled the valves, springs and keepers. I also drilled and tapped the cams for two #6-32 set screws each.  I had to get this far so I can measure between the ends of the valve stems and the flat part of the cams so I will know how long to make the yellow pieces I refer to as "lifters". I have a "theoretical" length in my model, but due to stack up of tolerances the actual measurement is going to be a bit different than the 'theoretical". Not a big difference really, only about .013", but when the valve lash is only 0.006" to 0.008", you have to get it right.


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## Herbiev (Feb 10, 2017)

Coming along nicely Brian. Can't understand the companies in the U.S not wanting to sell products to Canada.


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## Brian Rupnow (Feb 10, 2017)

Herbie, there has to be more to the picture than I can see. I don't know for sure, but I think American companies wanting to sell into Canada get hassled right to death by our taxes, tariffs, and political bull$h&t. One would not think that to be so, but there has always been issues buying stuff into Canada from USA. And every year it seems to get a bit worse.


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## Brian Rupnow (Feb 10, 2017)

Today after work, I made a pair of "lifters" out of 01 drill rod. They aren't real pretty, but they are dimensionally accurate. Since I don't have the bronze "bridge" that they fit into yet, I reamed a 3/8" hole in a piece of brass scrap, and turned the outer diameter to a snug "sliding fit".--Well, that's a lie.--I made them from 3/8" drill rod, which is so close to being a full 3/8" in diameter that it won't fit into a reamed 3/8" hole. I used #240 grit garnet cloth strips and "sanded" the piece of 3/8" drill rod in the lathe until it was a snug sliding fit into the reamed hole. Snug is good. If they are a bit tight in the bridge after I heat treat them, a bit of 600 grit compound will fix that in short order. The flat end is in contact with the cam. The hollow end fits down over top of the valve stem and spring keeper. Much careful measuring was done before I arrived at numbers that fit my particular situation. I haven't drilled the inlet nor the exhaust passages in the head and valve cages yet, so the valves will be removed, the drilling and tapping of passages completed, and then a complete assembly including the yet to be made bronze bridge will be set up to check clearances before hardening the cams and lifters.


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## Brian Rupnow (Feb 11, 2017)

Look what showed up at my house today. I'm impressed, they look great, but it makes me crazy that something that started out in USA for $46 ends up costing me $106 Canadian funds by the time it gets to my house.


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## Brian Rupnow (Feb 12, 2017)

This is a short video showing the operation of the overhead valve train in operation. Please let me know if you can see it okay.--Brian
[ame]https://www.youtube.com/watch?v=KgNTsMqnWvc&feature=youtu.be[/ame]


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## Ghosty (Feb 12, 2017)

Brian,
Could see it no problems. The "lifters" are called followers or cam buckets in this setup.

Cheers
Andrew


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## DavidLloyd2 (Feb 12, 2017)

Brian,
I can see it okay.

Cheers
             DavidLloyd


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## makila (Feb 13, 2017)

Good work Brian, the work you have produced is spot on to get the clearance right between the cam and the lifters.
I have built a similar overhead version and purposely left a bit of extra material on the lifters so that once the cam assembly is attached, small adjustments can be made to the face of the lifters to get the clearance required to ensure seating of the valves. This saves having to work to exact measurements during the major cam part machining, which might help some from having slightly off dimensions during manufacture. On full sized versions, they use small shims beneath the lifters and top of the valve stems to get the clearances right but that requires much more fiddly work making the shims on an engine this size.

Looking forward to seeing this one run.

Steve


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## Brian Rupnow (Feb 13, 2017)

I discovered this morning that I didn't have any 5/8" diameter brass to build an exhaust from. Lots of 1018 round steel 'shorts" though, so that's what I have for a muffler. I need to sand the o.d. a bit more to get any tooling marks out, but it's another part done. The carb I will be using with the correct adapter is also "posed" in the picture. The ports are drilled and tapped into the head and thru the valve cages, and the cams and cam followers will be heat treated later today.


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## Brian Rupnow (Feb 13, 2017)

Well, the cams are in the oven---Kinda sounds like the beginning of a song, doesn't it!! I heated the cams and the cam followers to a orange/ red (Had a piece of coat hanger wire thru the cams so I could manage them without flame hardening my fingers.) The followers have no thru hole, so they were supported by a "hook" in the end of another piece of coat hanger wire. I don't like to get things like this too hot. If you burn them (which is very easy to do with oxy acetylene) they are ruined. At what I thought was the right temperature they were lowered into a soda can of #30 motor oil and swished around. after they cooled, I pre-heated good wifes kitchen oven to 400 degrees and set them in an old cake pan, where they are quietly spending the next hour heat-soaking. At the last minute, after they were in the oven, I had a moment of self doubt--"Was that piece I cut thing out of really 01??--So, I grabbed the piece of material I had cut them from, ran out to the shop, heated the end of the rod and swished it around in the same oil till it cooled off. Then, back into the machine shop for the "file test". Yep, harder than the devil's horn!!! Now I have to go turn on the vent fan over the stove, before I stink up the house too much and lose my kitchen privileges.


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## Brian Rupnow (Feb 13, 2017)

I can't really tell what the 1 hour heat soaking at 400 degrees has done to the material, but the quenching in oil has certainly turned them black. Funny, they don't look as black in the picture as they do in reality. The piece of material that I hardened the end of to check and make sure it was really 01 material is undergoing it's own 1 hour heat soak right now. When it is finished, and cools off, I will re-try it with my file to see if I detect any difference.


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## Brian Rupnow (Feb 13, 2017)

I'm happy to report that my home-grown heat treat and tempering has come out very well. This is my "test and control" piece, which was heated to orange/red with oxy acetylene, quenched in oil, then heat-soaked in my kitchen oven for 1 hour at 400 degrees. Before the heat soak (tempering), a file just skated off with no cutting visible at all. After the heat soak, a file will cut it, as you can see, but it is still really hard. Without more scientific means to test what I have accomplished, I believe I can say this was a successful outcome.


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## Brian Rupnow (Feb 14, 2017)

After making my cams using the "quick and nasty" method in the vertical mill, I was curious about how closely the milled profile matched the actual design drawing, which asked for 125 degrees of cam influence. (that is the number of degrees that the cam actually is lifting the cam follower.) Since there is a 1:2 ratio between the camshaft and crankshaft, that translates to 250 degrees of influence on the valve during  one full rotation of the crankshaft. Which is fine.--The exhaust valve begins to open 50 degrees before bottom dead center, remains open thru a full 180 degrees of movement from bottom dead center to top dead center, then closes completely about 20 degrees into the intake stroke. I thought up all kinds of wild schemes on how to measure the angularity of my cams (they actually turned out "spot on" dimensionally.) I ended up doing what you see in the picture, which is extra neat because I didn't have to make anything. I have an old change gear with a hub  in it which has a 1/4" bore, that is used for the automatic carriage feed on my model sawmill. I put it and one of the cams on a piece of 1/4" shaft and put it in the chuck of my lathe. I then took my dedicated dial indicator with a flat "foot' on it which I use for setting up my four jaw chuck and set the "foot" against the cam. I stacked up some 1 2 3 blocks and some parallels to be the same height as the center of the chuck. Then turning the chuck by hand, I could see very clearly when the lobe on the cam started to affect the dial indicator, and put a mark on the gear face at the top of my stack of blocks. Then I turned the chuck by hand in the opposite direction until I seen the dial indicator needle start to move again, and scribed another line. The angular separation between the two marks was then measured with a drafting protractor. This yielded 103 degrees instead of 125 degrees, but that's okay. At 206 degrees of influence on the valves, I  will begin to open the exhaust valve 20 degrees before bottom dead center, stay open thru 180 degrees, and close 6 degrees after top dead center. My aim was not to have a high revving engine, so for a low revving engine this should work just fine.


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## Brian Rupnow (Feb 15, 2017)

The cylinder head assembly is all back together, and everything fits. Non of the parts I hardened or heat treated changed shape in any significant way. I have just had one of those "King Midas in reverse" afternoons, where everything I touched turned to poop!!! There is a thin brass spacer between the cams and the flanged bearing on each side to keep things positioned properly. I hunted around in my precious metals (brass and bronze) bin and found a very short piece of 3/4" brass that should have worked. First I made them too big around, matching the cam tower diameter, and not the flange bearing. Then I drilled the hole in the center undersize--(drill was in the wrong spot in the drill index.) Then I mounted them on a stub arbor to reduce the diameter and they ended up radically unconcentric with the center hole. Then I said something nasty, threw them in the waste box, and started over again with a new piece of brass.  At that point I decided I better quit for the day, so I detailed the piston and con rod. I don't often have afternoons like this, but when I do it really makes me appreciate the days when things go right!!!


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## Brian Rupnow (Feb 16, 2017)

This morning I have a piston on the go. It is going to be made from cast iron. Why?---Because when I buy cast iron to make cylinders from, I always buy a piece about 3" longer than I really need, so I have something to hang onto with the lathe chuck while the cylinder is being machined. All these left over bits from making cylinders eventually get recycled into pistons. I could have use aluminum and it would have worked just as well, but I didn't have any aluminum the right size. The outside diameter is turned to be 0.003" larger than the bore of the cylinder. That over-size will get addressed a bit later. I have put the round counterbore into the "open" end of the piston, and cut the ring groove with my .094" wide parting off tool. My next step will be to hone the inner bore of the cylinder with my 3 stone brake cylinder hone to knock down any high spots inside the bore (which was put in with a 1" reamer). Then I will "dress" the piston with 280 grit carborundum paper strips while it is still set up in the lathe until it just starts to act like it might fit into the end of the cylinder, but doesn't slide freely in. At that point I will remove the piston from the lathe and set it up in the chuck on my rotary table to complete the machining operations.


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## Brian Rupnow (Feb 16, 2017)

Remember how I said that you just want the piston to start into the cylinder, but not slide all the way in. All of the other machining operations are then finished on the piston, and my "special tool" which has a wrist pin sized cross hole in the end is slid into the piston, a dummy wrist pin is pushed into place and locked there with the wrist pin retaining screws. The piston is then coated with green diamond lapping compound, and then the piston is "wrung" into the cylinder in a sliding, twisting motion. I always find that this part is much harder and takes longer than I think it will. After an hour of pushing and twisting, and occasionally having to run out to the arbor press to get the piston "unstuck", the piston will go all of the way thru the cylinder, and is virtually an air tight seal. It would probably run this way with no ring on the piston at all. I will  now wash the inside of the cylinder and the outside of the piston with laquer thinners and an old toothbrush to remove any remaining diamond compound, and move on to machining a connecting rod.


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## Brian Rupnow (Feb 17, 2017)

I had almost finished this connecting rod yesterday, but after almost 12 hours in the shop I was quite happy to quit for the day when my wife got home at 7:45 from her job. Today I did the final clean-up and fettling on it and it is finished. The picture shows it setting with two tiny sealed ball bearings in the wrist pin end, and an oilite bronze bushing in the crankshaft end. My hands are sore today from wringing the piston into the cylinder yesterday.


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## Brian Rupnow (Feb 17, 2017)

Today I made crankshaft webs. I didn't originally plan on having counterweighted webs, but the weight of that cast iron piston really surprised me. I have been making pistons from aluminum for so long that I forgot how heavy a cast iron piston could be. I decided that this engine would need counterweights to offset the weight of the piston. The webs are made from 5/16" 1018 flat bar. I didn't realize it when I designed this engine, but 5/16" flatbar is not something commonly stocked by Barrie Welding where I buy most of my material. I ended up getting 3/8" flatbar and flycutting 1/32" from both sides to keep it from warping. Three of the holes are reamed to 0.3735", and one is drilled to 5/16". I will make the crankshaft from 01 drill rod, not because it has to be hardened, but because drill rod comes in at on size to .0005" over, while cold rolled 1018 comes in .0005" undersize. When you are pressing crankshafts together instead of machining from solid, that .001" difference between drill rod and plain cold rolled rod makes a big difference on how well the crankshaft stays together. The rod journal will be machined from 3/8" drill rod, and pressed into the driver side web. The main body of the journal that the rod sets on will be turned to 0.3125". This is going to be a two piece crankshaft, with a driver side and a driven side. The end of the rod journal that fits into the 5/16" drilled hole in the driven side web is a clearance fit.


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## Brian Rupnow (Feb 18, 2017)

Houston, we have a ---crankshaft!!!  One thing to be aware of when using drill rod for crankshafts. Since it is .0005" oversize, it won't fit thru the 3/8" ball bearings. The trick here is to determine exactly how much of the shaft must go thru the bearings (in my case, all of the shaft that isn't pressed into the webs), put it in the lathe, and work it down over its full length with 220 grit carborundum cloth strips. This is not hard to do, it's just time intensive and requires a lot of "Stop the lathe and try the bearing to see if it fits onto the shaft yet". The end of the shaft which is getting pressed into a 5/16" web plate is left 15/16" long, and not touched with the carborundum cloth. Turn down 5/16" of length at the end to .372". Then turn the next 5/16" down to 0.374". Use a thin strip of carborundum cloth to smooth the shoulder which results being 3 different diameters. Clean the parts which get pressed together with laquer thinners and a Q tip. The press fit is going to be more than a 2 ton arbor press is going to be able to handle. This pressing gets done in my big shop vice. You need a hollow socket or something to accommodate the part of the shaft which has been turned undersize because it is going to "stick thru" about 5/8" on the wrong side of the web when the pressing is completed. coat all the areas of the shaft which are going to be pressed with 620 Loctite, and have at it. After the shaft has moved about half way home, loosen of the vice in case things are going a bit crooked, then take it the rest of the way home. this is a very hard press fit. Trim the "stick thru" part with hacksaw or in the lathe, and you're done.


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## Brian Rupnow (Feb 19, 2017)

There is an undefined point when a craft begins to become art. These sidepates are getting pretty close to that point. I like them a lot. I know that there is two full days of work in getting them to this stage. The engine will look a lot more balanced once the gas tank is completed and fitted to it.----Brian


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## Brian Rupnow (Feb 20, 2017)

This morning I finished the angle that fits between the two sideplates and forms the central body of the "crank-case". Everything went together okay, but something didn't look quite right. Finally, I realized that I had misread my own drawing of the sideplates and put the recess for the 1/4" brass inspection door about 0.4" farther down from the peak that I had intended. Oh well, no harm, no foul. I can still get at the big end of the con-rod to give it a squirt of oil, and that's really all I wanted to be able to do.


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## Brian Rupnow (Feb 23, 2017)

Both bearing housings are machined and bolted up to the sideplates, and the sealed ball bearings and spacers are installed with a little skim of Loctite and an alignment rod. I like to give .001" to .002" clearance on the bearing housing bores. That lets the bearings align themselves when everything is assembled, and the alignment rod ensures that the bearings will all be lined up after the Loctite sets up. The bearing housings actually extend into the "crankcase" area, and will serve to locate the crankshaft side to side when it gets installed. at least, they would in a perfect world. I always seem to end up having to make an additional spacer/washer, or else skim a little material off to get things perfect.


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## canadianhorsepower (Feb 23, 2017)

Brian
what side is the carburetor going to be ???


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## canadianhorsepower (Feb 23, 2017)

canadianhorsepower said:


> Brian
> what side is the carburetor going to be ???



it should be on the opening side
 but closer to the ground to prevent vibration
not sure if that's clear:fan:


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## Brian Rupnow (Feb 24, 2017)

It will be on the side opposite to the timing pulley.


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## Brian Rupnow (Feb 24, 2017)

There isn't any particularly graceful way to mount a belt tensioning pulley on this engine, so it will be a simple ball bearing mounted on a 1/2" square piece of stock. The piece of stock will bolt to the engine sideplate.


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## Brian Rupnow (Feb 24, 2017)

So far, the news is good. With everything reassembled, the crankshaft rotates feely, the piston goes thru it's full travel, and the con rod doesn't hang up on the bottom of the cylinder. The timing belt I ordered seems to be the correct length. Other than a mount for ignition points, a flywheel, a belt tensioner and some assorted inspection plates the engine is almost finished.


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## Brian Rupnow (Feb 25, 2017)

Today I've made the gas tank, and I'm doing something that I haven't done for many, many years. In the pre mig days, I was an avid hotrodder, who patched up many rusted out antique car bodies. At first I used oxy acetylene torches and brazing rod, which gave fast and fairly easy results. Then, as I got into it deeper and deeper, I came to realize that the proper way to fix car bodies wasn't to braze patches over rusted metal, but was to cut the rusted metal out completely and replace it with new metal, not lap welded but butt welded with oxy acetylene and steel filler wire. I became an excellent welder using only steel welding rod, and fusion welding body metal with no filler rod at all, just melting the old metal and new metal enough to let them flow together and immediately fuse without filler rod. This is something that takes years of practice, and I became very good at it. Practice DOES make perfect!!! So---Today I welded the end caps and filler neck to the steel pipe which forms the body of the gas tank for this engine using oxy acetylene and steel filler rod. Why?--Just to see if I still could, and to avoid having a ring of braze or silver solder showing at the ends of the tank. I'm not sure yet how well this is going to work. If I end up with leaks that I can't weld shut, then I'll have to start over again on the tank.


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## Brian Rupnow (Feb 25, 2017)

Well, that was ahhhh---interesting. I can still steel wire weld with oxy acetylene. I have a few minor leaks at one end. (the tank is full of water in the picture.)  One thing about welding with steel wire--if you have a leak, you can go back and reweld the leak area without melting anything else out. Poor little tank looks a bit like a roasted turd!! I can do a lot of sanding and clean-up to improve the looks, but I have some heat related pitting around the filler neck that isn't going to sand out. I'll think about this overnight. If it doesn't clean up respectably, I may use a bit of bondo on the pits and paint the tank. It was fun to weld it this way, but my eyes at 70 don't enjoy looking into the melt puddle nearly as much as they did at 40.


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## Brian Rupnow (Feb 26, 2017)

I've been chasing leaks all morning. I'm about at the point where I may take Sid's advice and try a different method. This is one of those situations where I had to "Try it and see if it worked". I'm not out any money. All the parts are scrap I had laying around. The tank body was a horrible old piece of galvanized pipe that I dug out of my scrap steel bin. If I don't achieve a leak proof tank in the next 20 minutes or so, I will buy a new piece of black steel pipe at the hardware store and silver solder the end caps and filler neck in place.


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## dnalot (Feb 26, 2017)

Nice, what did you use for welding wire, a coat hanger?

I would recommend using a 4 percent silver content soft solder. Easy to do and works at low temperature so no problem with burning the base metal or warpage. 

Mark T


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## Brian Rupnow (Feb 26, 2017)

I used 0.060" diameter copper coated steel welding rod. The same stuff I welded 100 old car bodies together with in the 1980's. Give me a little credit here. We don't do coat hanger wire.


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## Brian Rupnow (Feb 26, 2017)

At this point, I'm going to declare a complete and utter "FAIL" on the gas tank. The welds were fine, albeit somewhat lumpier than they were when I was doing that a lot in the 1980's. I just couldn't get ahead of the pinhole leaks. Nothing ventured, nothing gained. I did save the fancy little plate bracket that holds the tank to the engine. Later this week, I will try again with a new piece of black steel pipe from the hardware store, and brass endplates silver soldered into place. As I said before, I don't do well with soft solder.


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## dnalot (Feb 26, 2017)

Hi



> I used 0.060" diameter copper coated steel welding rod. The same stuff I welded 100 old car bodies together with in the 1980's. Give me a little credit here. We don't do coat hanger wire.



Sorry Brian. We don't get a chance to pull your chain very often so I couldn't resist. 

Mark T


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## Brian Rupnow (Feb 26, 2017)

Dnalot--You asked the right question. You just asked it 55 years too late. The summer I was 15, I wanted a go-cart, so bad that I couldn't think of anything else. I scoured the town dump and found an old baby carriage for wheels, and some bed angles for a frame. The guy who lived a mile down the road from our place had a gravel pit, a dump-truck, a bulldozer, and a set of oxy acetylene tanks. I asked the man if I could borrow his welding rig to weld up the frame for a go cart. He was a pretty good hearted guy and said yes, so I drove my dad's old International pickup down to the pit, loaded up his tanks and regulators, took them home, and welded up a go cart frame----with coat-hangers for welding rods. This story should have a happy ending-----it doesn't. His welding rig was old, and everything leaked a little bit, and I forgot to shut the tanks off when I was finished. Next day I went to take them back to him and seen what I had done, and that both tanks were empty!! My dad had to pay to get both tanks filled, and I remember it cost $35.00. That doesn't sound like much, but my dad only made $50.00 a week working in the sawmill in the summertime.----He was not impressed, at all.---Brian


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## dnalot (Feb 26, 2017)

Hi Brian

You may get a chance at payback. As it happens today I start making the fuel tank for my build of the Snow Engine. 

Mark T


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## Brian Rupnow (Mar 1, 2017)

I've been really busy with "real" work, in and out of the hospital for tests (which were okay, than God), and today I'm sick with a cold. Ah well, sometimes life sucks a little. After my gas tank fiasco, I decided to do something else on the engine. I have finished the points mounting bracket, the ignition cam, and the brass "inspection cover" which will let e open the crankcase to give a squirt of oil to the con rod big end. I still have to make and add in the filler plate that sets between the two engine sideplates above the brass inspection door.


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## Brian Rupnow (Mar 1, 2017)

There is often more to a story than meets the eye!! Have you ever heard the phrase "a comedy of errors"? When I went to make my ill fated gas tank, all I had in my scrap bin was one ugly, nasty, short piece of galvanized pipe or tube, which was close to the right outside diameter---just enough oversize that a few passes on the outside to peel off the galvanizing, and it would be perfect for a gas tank. I know it is dramatic overkill, but I like the tubing I make my gas tanks from to have about a 3/16" wall thickness. Not because any particular strength is needed, but so I can put a nice little counterbore in the end of the pipe equal in depth to the material I am going to use for endplates. This gives me a "shelf" to set the endplate on while I solder or silver solder the endplate in place. The ugly, nasty piece of pipe I had would also require a few passes on the inside with a boring tool to clean the galvanizing of the inside as well. I set the pipe up in my lathe, and there was no way I could hold it in the 3 jaw so it would rotate smoothly without a big "wobble" on the outboard end. I tried different positions in the chuck, I tried turning it end for end, I even tried my "nudging" tool which is basically a ball bearing mounted to a piece of material that I can mount in the quickchange toolpost and push on the outboard end of the pipe until it "runs true" before tightening the chuck completely. Nothing worked, so screw it---I will machine the wobble out of it!! After taking multiple passes on the outer diameter, it ran true, but then it was quite obvious that the outer diameter was no longer concentric with the inner diameter.--At least at the outboard end---and, if I tried to bore the galvanizing out of the inside I would end up with a paper thin wall on one side of the pipe. With a ring of silver solder holding the endcap on the pipe, it would have been very obvious that something wouldn't look right.--So---Compounding "dumb" with "stupid", I decided to steel wire weld the ends in place, which would leave no tell-tale ring of solder. We all know how this worked out. The galvanizing on the inside of the pipe kept causing so many pin holes in the welds at my endcaps, that I had to reweld  both ends numerous times to plug leaks. Eventually, I had poured so much heat into this poor, would be gastank, that it looked like a roasted turd at which point, I decided to throw in the towel. The upshot of this rant, is that today I bought a new piece of ungalvanized, unrusted tubing to make gas tanks from, and spent a chunk of the Rupnow fortune on a "Bullnose" center with bearings that fits into my lathes tailstock. If you don't know already, the purpose of a "bullnose" is to support the outboard end of a pipe being turned in the lathe. Hopefully, the next gas tank attempt will go a little better!!


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## Goldflash (Mar 1, 2017)

Some of those old galvanised fittings were wrought / malleable iron and very hard to weld with or without the galv


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## Brian Rupnow (Mar 4, 2017)

Hah!!! I knew there was a gas tank in there. All I had to do was gather up enough karma to set it free. Considerably better results this time than last time around. I am suffering from the Head cold from Hell, and should have been taking it easy today, but I couldn't rest until I had redeemed myself gas-tank wise.


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## Brian Rupnow (Mar 4, 2017)

Mr Rupnow IS getting close. Almost all of the easy parts are made. The belt tensioner is an easy part, and I haven't made it yet. I still haven't figured out what to do for a flywheel. This has ended up being an expensive engine to build. When I include the price of the bearings, the aluminum, the pulleys and belt, the carburetor, the sparkplug, and the ignition points and condenser, we're north of $250 on this one. I might have to sell the plans for this one to recoup the cost of building it.


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## Brian Rupnow (Mar 5, 2017)

We've got some tension here today---But not in a bad way. This morning I finished off the belt tensioner and mounted it to the engine. I was a little bit worried about the head gasket adding to the center to center distance of the belt pulleys, but since the head gasket is only .032" thick, it didn't really have any bad effect. So, I made a head gasket and installed it just to be sure, then made up the 1/2" square steel bracket with a 3/8" stub shaft on the end of it and used a sealed ball bearing as the actual "rolling member" that contacts the back side of the timing belt. The belt doesn't really need much tension on it. Just enough to keep it from "skipping a cog" and throwing out the valve timing.


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## Brian Rupnow (Mar 5, 2017)

This whole flywheel thing is beginning to eat my lunch!! I could buy a piece of brass and make a pretty, functional flywheel, but I've done that half a dozen times. I could make a two part flywheel, with an aluminum inner hub and heavy wall pipe outer rim, but that too is something I've already done a number of times. Right now my mind keeps going to the fact that there has to be a zillion dead chainsaws and weed whackers out there kicking around in the small engine repair places. I may have to pursue that line of thought. My flywheel can be as large as 5 3/8" diameter. I have a mill. I have a lathe I should be able to modify almost anything to work. Thinking----thinking---


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## DavidLloyd2 (Mar 5, 2017)

Brian
I think it will be hard to find and fit a flywheel off a chainsaw or weed whacker. Most of them have magnets in them,
I ended  up finding some 6in x 6in x1in  steel from my local scrap yard and cutting it on my
 band saw and finishing off in the lathe and mill,

DavidLloyd


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## dnalot (Mar 5, 2017)

Hi

Take a look at this

https://www.mcmaster.com/#casters/=16ml7z7

Find something like that used and you would be off to a good start.

Mark T


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## Barnbikes (Mar 5, 2017)

Why don't you use the flywheel and the points from the chain saw and not worry about battery connections.


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## Goldflash (Mar 5, 2017)

old cam timing pulleys from the car wreckers


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## Brian Rupnow (Mar 6, 2017)

One very small last minute change to the "access hatch" that lets me oil the big end of the con rod. In my original plan, this was a small square brass plate held in place by neodymium magnets to allow fast removal to let me give a squirt of oil to the big end of the con rod. This all worked fine until I decided to make the filler plate which sets directly above the "access hatch" between the two main sideplates. I soon came to realize that there was really no good, simple way to do that because of all the other bolts buried in the sideplates which hold the cylinder mounting block in place. A few minutes head scratching, and I had it solved. ---Just make the lift off cover plate long enough to cover that area as well. I decided to forgo brass and make the new cover plate from aluminum, and it worked out really well. In the second picture you can see the reverse side of this cover plate, and see how much material was hogged out of the center to give clearance for the counterweights on the crankshaft web plates. You can also see the neodymium magnets attached in their respective counterbores with J.B. weld. The piece of heavy angle which forms the crank-case body has also been drilled and magnets J.B. welded into sockets in it as well, positioned to line up with those in the access hatch. (You can probably see the c-clamp and the scrap aluminum plate set in place to ensure that these magnets set below the surface of the pockets they are in on the engine.) I just did that this morning and it has to set up for 24 hours. With this final change, I have completed the engine except for the flywheel.


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## Brian Rupnow (Mar 6, 2017)

On the subject of built up flywheels--This is the way I see it today. A solid steel hub, with keyway, set screws, and built in "nose" for my starter spud. Cheap, nasty, and can be made from stub ends I have left over in my shorts bin. A web made from 3/16" aluminum plate, and an outer rim cut from a section of heavy wall tubing. Wouldn't be as pretty as bronze or brass, but would be very cost effective, and lends itself very well to painting if I choose. Maybe even paint gas tank to match flywheel.


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## Brian Rupnow (Mar 6, 2017)

Well Sir!!---That was worth a quick trip downtown to my metal supplier/machine shop. A nice piece of 660 bronze, 5" o.d. x 3" i.d. x 1" long out of their "cut-offs" in the bronze rack for the princely sum of $10.00. I have material here for the hub and web. all I need now is the energy to make it happen.


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## Brian Rupnow (Mar 6, 2017)

Today got to see the built-up flywheel design finalized, and a good start made on the center hub. That center hub was an end of 1144 stress-proof left over from building a one piece crankshaft.  My goodness, that is lovely material to work with!! I save all of my "chucking stubs" because they work great for little pieces like this. I'm finally beginning to recover from the "Head cold from Hell", so I'll probably be working on a design contract tomorrow "on site". If I have any energy left at the end of the day, I'll finish this part off and start on the "web" of the flywheel.


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## Brian Rupnow (Mar 7, 2017)

Another day--another part. Actually, I worked most of the day at a factory that makes spinforming lathes. I got home and immediately cut the 1/4" aluminum out of a piece of 1/4" aluminum angle. The material in angles isn't really flat like plate, that is why you see some evidence of turning on the face. I will "true it up" after I get farther into the flywheel build. The picture in the chuck was snapped just after I had test fitted the hub before taking the part out of the chuck. It fit without requiring further work, so I took it out of the lathe and snapped a pic of it setting on the engine.


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## Brian Rupnow (Mar 8, 2017)

I don't have to show up at the pickle factory until 9:00 so I had time to put in the counterbore for the aluminum web and face one side of my 660 bronze ring this morning. Thru good fortune and lots of measuring I have managed to keep all of my concentric fits nice and tight, so I don't expect much runout on this flywheel when it is all assembled. Tonight I will flip the ring around, hold the bored inner diameter with expanding chuck jaws, and finish machine the outside diameter and clean  up the other face.


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## Brian Rupnow (Mar 8, 2017)

OH YEAH!!! Nothing says it quite like bronze!!! I really like this, and as I had hoped, it fills out the engine so it doesn't look skinny anymore. Now I have lots and lots of holes to tap and some "lightening" holes to drill in that web. The "lightening holes" don't really do anything. It's just that without them a video doesn't show the engine running all that clearly. There is about 1/8" of clearance between the side of the flywheel and the gastank. You will notice a little bit of brass "jewellry" on the carburetor. Those Traxxas carburetors don't have any spring to hold the throttle  in any particular position, so if you start the engine it immediately tries to run at wide open throttle. I have added a small return spring and idle adjustment to this one.


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## Brian Rupnow (Mar 9, 2017)

The engine is finished mechanically. The last thing I had to do was cut a keyway in the crankshaft, and that is done and the completed flywheel is mounted. I have to pick up a set of ignition points and a condenser for it (I have an old set of points on it right now that I use for "set-up" purposes). If I don't run into any unforeseen issues, I MIGHT have a runner in the next few days.


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## Ghosty (Mar 9, 2017)

Brian,
It is really starting to come together. It's looking good too. Could you use a smaller timing gear setup?

Cheers
Andrew


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## Brian Rupnow (Mar 9, 2017)

Ghosty--there is a factor called "minimum wrap diameter" that deals with how small the crankshaft pulley can be. This differs between manufacturers of belting, but the bottom line is that if the pulley becomes too small in diameter, the belt has to flex so much to accommodate the smaller pulley that the belt fails very soon. I don't really know how much smaller I could go, but I don't mind the proportions the engine has now. ---Brian


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## Johno1958 (Mar 9, 2017)

I like this engine a lot Brian,can't wait to see she runs
Cheers
John


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## Brian Rupnow (Mar 9, 2017)

Thanks Johno--I like this engine a lot myself. I just put the new points and condenser on it, and set the ignition timing and valve timing. I have looked a little closer at the brass bit I have attached to the carburetor and decided that it is more hindrance than help. Not all of my ideas pan out as well as I had originally hoped for them. I will take that brass bit off tomorrow and craft a better throttle lever.---Brian


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## Brian Rupnow (Mar 10, 2017)

And so, boys and girls, Mr Rupnow must have done something right in a previous life, because the engine started this morning as soon as everything was hooked up. I made a wild grab for my video camera and made a video of the first run, but there was so much movement that a person would have gotten sea-sick trying to watch it. After things calmed down a little bit, I made a second video of the engine running with everything a little calmer. I originally had some brass fittings on the carburetor to control the free swing of the throttle arm, but it didn't work out terribly well so I removed it and just attached an aluminum extension handle to the small throttle lever that came on the purchased Traxxas carb. In this video you will see my low-tech rubber band holding the throttle closed because without it the damned throttle arm wants to swing into the wide open position and my engine revs so high it almost scares me to death. I am extremely pleased with how well this thing runs, and how little screwing around was required to get it running this well. somebody please let me know if the video shows up alright.---Brian Rupnow
[ame]https://www.youtube.com/watch?v=N7_klnlI3Ak[/ame]


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## dnalot (Mar 10, 2017)

Well done, I love the slow idle. I'm going to miss reading your frequent posts. So whats next?

Mark T


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## DavidLloyd2 (Mar 10, 2017)

Brian
         Video shows up good this end,

DavidLloyd


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## Johno1958 (Mar 10, 2017)

Brian 
You must be pleased as punch. A very nice runner.
Cheers 
John


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## Ghosty (Mar 10, 2017)

Brian,
Congrats, great work as usual. And yes the video is good.

Cheers
Andrew


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## Herbiev (Mar 10, 2017)

Another great engine Brian. Well done and thanks for sharing.


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## Brian Rupnow (Mar 10, 2017)

Thank you, gentlemen. This build got me thru the coldest, darkest part of the winter, and overall it went very well, with no do-overs except for the ill fated gas tank. I am always greatly gratified when an engine fires right up and runs first try. When I look back at my first  i.c. engine attempts like the Webster and the Kerzel, and all the horrible issues I had with non sealing valves, it makes me give my head a shake. I don't do very much different now than I did five years ago when I first started building i.c. engines, but we must learn by our mistakes, because I seem to have a lot fewer problems now. It's been a fun ride, and I thank all of you who followed along during the build.---Brian


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## Brian Rupnow (Mar 11, 2017)

And just to show that I'm not a total barbarian, I dug around in my box of tension springs and found one that will act as a throttle return spring so I can get rid of the rubber band!! It is going to attach to that head bolt nearest to the other end of the spring, but first I have to buy a longer #6 shcs to replace the one that is in there already.


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## rac37 (Mar 11, 2017)

Very nice Brian, Will be interesting to see what is next.
 Bob


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## Cogsy (Mar 11, 2017)

Congrats Brian, another great runner. It seems from the video that it sounds very different to the Rupnow Vertical and I can only guess it's because the intake valve is not atmospheric? It almost makes me want to build another vertical with a cam operated intake valve just for comparisons' sake, but I just don't have the time.


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## Brian Rupnow (Mar 12, 2017)

Cogsy--that is something that I have noticed as well. All of my engines have a distinctive sound, and all of the engines with two cam driven valves sound different than the ones with atmospheric intake valves.---Brian


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## Brian Rupnow (Mar 12, 2017)

With the completion of this engine I have now built just about every version of the internal combustion engine. I have built  flathead engines, overhead valve engines, overhead cam engines, two cycle engines with no valves, hit and miss engines, and both atmospheric valves and cam operated valves. I know there are more "strange one of" versions of the i.c. engine out there, but I have just about covered all of the popular styles. I have not, and probably will not build a radial i.c. engine, although I have built a 5 cylinder radial "steam engine".


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## Cogsy (Mar 13, 2017)

Brian Rupnow said:


> I have not, and probably will not build a radial i.c. engine, although I have built a 5 cylinder radial "steam engine".


 
What about a single cylinder, stationary crankshaft engine where the cylinder revolves around the crank? That sounds like a design challenge you could sink your teeth into!


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## Brian Rupnow (Mar 13, 2017)

Cogsy said:


> What about a single cylinder, stationary crankshaft engine where the cylinder revolves around the crank? That sounds like a design challenge you could sink your teeth into!



A bit too dangerous for me Al. I damned near lost a finger to an engine like that when I was about 13 years old. I had an old single cylinder washing machine engine that you started by wrapping a pull cord around the flywheel pulley and giving it a yank. Being 13 years old, I only had half a brain yet, so didn't have the engine bolted down to anything. The engine immediately started, flipped over onto it's flywheel, and then proceeded to spin around like a whirling dervish between my feet. In a panic I made a grab for the sparkplug wire and something metal hit the knuckle on my right index finger, almost tearing it off. The motor eventually quit on it's own, but I still carry the scars from that event on my knuckle. I don't want to go for a repeat.---Brian


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## Brian Rupnow (Mar 13, 2017)

We've reached the end of the trail, partner. This engine is done like dinner. The only thing left is a video of it doing a bit of honest work, and I made that about half an hour ago. I have no idea of what I may do next, but it won't be for a while. I love these builds, but when I have finished one, I don't want to machine anything for a little while.----Brian
[ame]https://www.youtube.com/watch?v=A8aKoDtPxc0&feature=em-upload_owner[/ame]


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## ShopShoe (Mar 14, 2017)

Brian, Of course I enjoy it. I understand the need for a rest: Have at it!

I also hope to see a future build of something from you: They are all fun to follow and quite instructional. Rest now, but I think your brain might start itching with a new idea later.

Best of luck.

--ShopShoe


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## Brian Rupnow (Mar 17, 2017)

Today I'm at home for the first time in a week, as I've hit a temporary roadblock in the development of a spinforming lathe for a customer in Barrie. That's just fine, because I have a little project I want to take care of. The overhead cam engine works fine, but like all air cooled engines, it starts to suffer after about 15 minutes continuous running with no air movement to carry heat away from the cooling fins on the cylinder. I just happen to have a plastic fan 3 1/2" in diameter that I have rescued from something, but the pitch is wrong for my motor. However, the belt tensioner bearing revolves opposite to the crank and camshaft on that side of the engine, and is in a location where the fan would do the most good in terms of directing air flow over the cylinder. Todays exercise will be to find a way to attach the fan to the tensioner bearing so as to provide some cooling for the cylinder.


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## Brian Rupnow (Mar 17, 2017)

So, here's the way it goes---I've had a 1 1/4" diameter length of round 316 stainless kicking around my shop ever since I built the Kerzel about a century ago. First step was to profile the end of it to fit into the recess in the back of the plastic fan. Second thing to do was try the fan on for fit before I tore down my set-up.


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## Brian Rupnow (Mar 17, 2017)

Third thing to do was part off the required length (I love parting off under power feed but it scares me right to death.), flip the part around and counterbore the other side for the bearing--very light press fit. Fourth thing to do was use 638 Loctite on the bearing side and two part epoxy on the fan side, and put everything together.


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## Brian Rupnow (Mar 17, 2017)

Now comes the tricky part---Taking the old belt tensioner bearing off and putting the new bearing/fan/adapter hub in place without letting the belt go slack and jump a tooth on either pulley. This would of course throw the valve timing out of whack, and I got so lucky with the very first time I set it up that I don't want to have to do it again.


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## Brian Rupnow (Mar 17, 2017)

And here we have a rather nasty picture of the finished installation. Black never shows up very well in these digital photos using a flash. Tomorrow I will machine a cool little divot to plug the hole in the center of the fan and try to get a video up. everything works slick when turned by hand.


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## Brian Rupnow (Mar 18, 2017)

I follow the machining forums a lot, and one of the things I take note of is the weird and wonderful set-ups that people use to cut unconventional shapes with their lathes. The brass "dress-up" part on the face of the fan required a set-up that I have never attempted before. As you can see in the picture, it's not just a disc of brass. Rather, it is a shallow cone, like the old Dodge Lancer wheel-discs. There is a 0.300" diameter "spigot" on one side which fits into the hole in the center of the fan. I turned it first, then parted off the 1.5" diameter brass to about 3/16" thick. I flipped the part around in the chuck, then with the lathe running in reverse I used my longest carbide tipped boring tool to reach out and machine the disc from the center outward towards the back of the lathe in successive passes using the top-slide manual advance handle until I had a nice shallow cone formed. I am very impressed how well that method worked. I have epoxied the .300 diameter "spigot" into the hole in the center of the fan, and I think it looks quite "dashing". I will let the epoxy set up for an hour, and then put up a video. I have test ran the engine with the fan in place before I committed myself by epoxying the brass cap in place, and the fan puts out a very respectable breeze.


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## Brian Rupnow (Mar 18, 2017)

As promised, here is a video of the engine with cooling fan running.
[ame]https://www.youtube.com/watch?v=T3tudwO4NZA[/ame]


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## ShopShoe (Mar 20, 2017)

That brass cap really dresses up the fan. I like this one even more, now.

I've only ever made a shape like the brass cap myself by accident and by problems with my lathe. Now I gotta try it on purpose.  Thanks for posting this refinement.

--ShopShoe


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## Brian Rupnow (Dec 26, 2017)

I have recently had a request for a set of the plans for this engine from a gentleman in USA, so have been busy as a Boxing day Beaver this morning converting all of my Solidworks files to .pdf files. In my opinion this is one of my more interesting engines, and as you have seen by the posted video, it is a great performer. If you wish to buy a set of the plans to build this engine, I charge $25.00 Canadian funds for the plans, all saved as pdf files.---Brian


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## Brian Rupnow (Feb 10, 2018)

A gentleman  in South Dakota just finished this engine, based on the plans I sent to him. He discovered a few tweaks that were required to the drawings, but he has a runner, and it looks really good. I have updated the drawings to reflect any changes that were required. So--now there are two of these engines in the world. Mine and Jacks. I think this is one of the prettier engines I have designed.---Brian


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## Sleddog (Feb 11, 2018)

Brian Rupnow said:


> A gentleman  in South Dakota  just finished this engine, based on the plans I sent to him. He discovered a few tweaks that were required to the drawings, but he has a runner, and it looks really good. I have updated the drawings to reflect any changes that were required. So--now there are two of these engines in the world. Mine and Jacks. I think this is one of the prettier engines I have designed.---Brian



And a video of it running. 


https://youtu.be/OC3Udla2sIE


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