# Snow engine thoughts



## Gordon (Dec 24, 2019)

A couple of years ago I built a Snow engine and had it running fairly well. Recently I have been going back to past builds and trying to get them to run better. The Snow had rather poor compression after setting so I ended up making some new rings and trying some other things. When I put compressed air (20-30 PSI) into the cylinders everything seems to seal and have minimal leaks. When I turn it over by hand it does not seem to generate much compression. I finally came to the conclusion the the garter spring seals were expanding when enough pressure was applied but not sealing at lower pressure. I am thinking about trying string packing similar to what I would use in a steam engine.


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## Harry. (Dec 24, 2019)

What about PTFE? Would that be better for compression in low pressure applications ?


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## dnalot (Dec 24, 2019)

I built the Snow Engine but never got it to run more than a couple of minutes. Tried a number of different intake manifolds, new rings, new shaft seals. I found two main problems , the intake manifold would get very cold and the shaft seals would quickly start leaking. Finally declared it a failure. But it looks great on the shelf. 

If you get yours to run well I will be very excited. 

Mark T

Here is a photo for those not familiar with this engine


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## Gordon (Dec 24, 2019)

I have tried playing around with some various seals and I have found that the garter spring seals hold well at 30-40 PSI and leak much worse at 10 PSI. My theory is that by the time the seals start to work the piston is already heading the other direction so you never really build up a compression stroke.


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## mfrick (Dec 24, 2019)

Hello to All  Merry Christmas and have a Happy New Year.

So several years ago I built the Snow Engine, I doubled it in size so the bore is 2 inch, the piston rod is 5/8 chromed 1045 material cylinders are cast iron with steel housing the fly wheel came off an Ideal hit and miss engine. 
I had tons of trouble with the seals and I changed to Chevron Packing made of Teflon put three rings in each head and compressed with the plate covering the water chamber, since doing this I have had great compression and the engine runs fairly well. I purchased the seals from McMaster Carr.


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## mfrick (Dec 24, 2019)

So I didn't get all my photo's loaded of the Snow Engine so I will try again.

Mike


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## Gordon (Dec 24, 2019)

mfrick said:


> Hello to All  Merry Christmas and have a Happy New Year.
> 
> So several years ago I built the Snow Engine, I doubled it in size so the bore is 2 inch, the piston rod is 5/8 chromed 1045 material cylinders are cast iron with steel housing the fly wheel came off an Ideal hit and miss engine.
> I had tons of trouble with the seals and I changed to Chevron Packing made of Teflon put three rings in each head and compressed with the plate covering the water chamber, since doing this I have had great compression and the engine runs fairly well. I purchased the seals from McMaster Carr.


Thanks. That looks like it could actually work. The stem packing string does not work.


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## Rustkolector (Dec 25, 2019)

Gordon,
I am presently rebuilding my Snow engine also. Previously I had made a number of changes to my engine and had it running quite well and slowly. Combustion had improved to the point where the exhaust was dry. It was burning the oil in the fuel to the point where it was creating blue smoke. To control the smoke level I was trying different oils and began cutting back the oil in the fuel. Unfortunately, I went too far and seized it up scoring the rings and cylinders. So I have refinished the cylinders .003" larger with new pistons and a few other changes. It is just about finished but I still have a few issues to resolve. That said, I have never had any problems with the original Buna N seals leaking and my engine had a fair number of hours on it. The first thought I had is that you might have your seals installed backwards. When installed as designed, with the lips facing the combustion chamber, the lips should grip the shaft tighter as cylinder pressure increases. 

I have never built a good compression tester, but my engine always had good flywheel bounce back when hand spinning it. One thing I sadly discovered when I completely disassembled my engine was that it had a lot of cylinder and piston rod corrosion. 12L14 is a great cylinder material on a 4 stroke engine, but only if properly maintained, especially immediately after stopping the engine.  My drill rod piston shafts were both badly pitted over a large area, BUT the original seals were not leaking when I seized it. 
Jeff


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## Gordon (Dec 25, 2019)

Rustkolector said:


> Gordon,
> I am presently rebuilding my Snow engine also. Previously I had made a number of changes to my engine and had it running quite well and slowly. Combustion had improved to the point where the exhaust was dry. It was burning the oil in the fuel to the point where it was creating blue smoke. To control the smoke level I was trying different oils and began cutting back the oil in the fuel. Unfortunately, I went too far and seized it up scoring the rings and cylinders. So I have refinished the cylinders .003" larger with new pistons and a few other changes. It is just about finished but I still have a few issues to resolve. That said, I have never had any problems with the original Buna N seals leaking and my engine had a fair number of hours on it. The first thought I had is that you might have your seals installed backwards. When installed as designed, with the lips facing the combustion chamber, the lips should grip the shaft tighter as cylinder pressure increases.
> 
> I have never built a good compression tester, but my engine always had good flywheel bounce back when hand spinning it. One thing I sadly discovered when I completely disassembled my engine was that it had a lot of cylinder and piston rod corrosion. 12L14 is a great cylinder material on a 4 stroke engine, but only if properly maintained, especially immediately after stopping the engine.  My drill rod piston shafts were both badly pitted over a large area, BUT the original seals were not leaking when I seized it.
> Jeff


I do have the seals installed correctly. When I put compressed air in the cylinder I do not have any leaks except at the rod seal. The lower the pressure the more air leakage. Mike suggested V ring seals from McMaster and that looks like a possibility but it will require a new head to accommodate the larger 11/16 OD seal. I am not getting any appreciable bounce back when I turn it over by hand. I have an adapter which I can put in the spark plug hole with a pressure gauge. The gauge bounces up to about 10 PSI and immediately drops back to 0. The rings are sealing because when I put pressure in the cylinder it does not bleed through to the other cylinder on the opposing side. Obviously I am missing something.


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## Gordon (Dec 25, 2019)

I just had a thought about the seals. I wonder if the seal is being compressed in the retaining cage. In order to seal air must get behind the spring loaded lip to push it out against the rod. If it is compressed longitudinally it is sealing the face and air cannot get to the spring area to expand the seal. Counterboring or countersinking should answer that. Probably worth a try.


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## Rustkolector (Dec 25, 2019)

Good idea Gordon. My seals (no garter spring) measure .122-.124" thick and adding a head gasket space of about .012" would leave a seal pocket depth exposed to compression and combustion pressures of about .017" between the seal and rear of the bushing (.470 - .340 - .125 + .012"). This would vary depending on your seal thickness and gasket material. I use Teflon gaskets which don't compress much.

One more little bothersome item I found when I disassembled my engine was that the single piece head gasket area directly exposed to the coolant had bulged into the head water jacket space greatly reducing water jacket volume (estimated 50%), and likely coolant flow. This happens with fiber and Teflon gasket materials. I use antifreeze to prevent water jacket corrosion which might have contributed to this gasket deformation. I have changed to a two piece head gasket leaving the entire water jacket space open.
Jeff


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## Gordon (Dec 25, 2019)

Rustkolector said:


> Good idea Gordon. My seals (no garter spring) measure .122-.124" thick and adding a head gasket space of about .012" would leave a seal pocket depth exposed to compression and combustion pressures of about .017" between the seal and rear of the bushing (.470 - .340 - .125 + .012"). This would vary depending on your seal thickness and gasket material. I use Teflon gaskets which don't compress much.
> 
> One more little bothersome item I found when I disassembled my engine was that the single piece head gasket area directly exposed to the coolant had bulged into the head water jacket space greatly reducing water jacket volume (estimated 50%), and likely coolant flow. This happens with fiber and Teflon gasket materials. I use antifreeze to prevent water jacket corrosion which might have contributed to this gasket deformation. I have changed to a two piece head gasket leaving the entire water jacket space open.
> Jeff


I have not tried O rings. I will try that next. I tried plumbing string packing and that did not work. It would not stay in the recess long enough to assemble it.


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## gld (Dec 25, 2019)

Gordon
 A few years ago I rebuilt my snow using vitron o rings on the Pistons. In the process I install stainless steel sleeves, and stainless steel piston rods. The O-rings will give better compression (no leakage through a gap) less friction which equates to easier starting and cooler running.


That's a very nice looking engine you have. I should think with the increased bore and flywheel weight, that engine should be able to run very slow. When you get it running, post a video, and tell use how slow it will go.
Gary

BTW where are you located?


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## mfrick (Dec 25, 2019)

I'm located in Port Angles WA. I haven't had the Snow Engine running since August, need to get it out and crank it up after the holidays I will try to find some time to crank it up and get some video to post.  Just installed a new lathe so now I need to put my shop back together, then I will have some spar time.

Mike


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## Gordon (Dec 27, 2019)

As I am doing more experimenting it appears that a lot of my leakage may be around the piston rod at the piston which allows the pressure to bleed from one cylinder to another. For instance when cylinder #1 is under pressure it bleeds into cylinder #2 and when cylinder #2 is under pressure it bleeds into cylinder #1. I found this by pressurizing #1 and if there is no spark plug in #2 I have air coming out of the open spark plug hole. I am presently tearing things apart and putting epoxy around the piston rod in the piston. This is not obvious until the opposing spark plug is removed.


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## mfrick (Dec 27, 2019)

A good way to stop the leakage around piston rod is to use some Loctite I used Red on mine and zero leakage  if you need to disassemble just heat piston up with a torch.

Mike


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## Rustkolector (Dec 28, 2019)

Gordon,
How did you determine the air leak past the piston was from the piston rod clearance and not the piston rings? 
Jeff


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## Gordon (Dec 28, 2019)

Rustkolector said:


> Gordon,
> How did you determine the air leak past the piston was from the piston rod clearance and not the piston rings?
> Jeff


I took the head off from #4 cylinder and put air pressure into #3.


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## Gordon (Jan 4, 2020)

This thing continues to baffle me. I seem to have the leaks fixed but now the problem is that it fires #3 & #4 cylinders but not #1 & #2. I have checked valve timing and ignition timing and all four cylinders seem to have the same timing. It fires #3 & #4 and it will continue to kind of run for 10-15 seconds but with #1 & #2 resistance it just bogs down and quits. It only seems to fire when the engine is almost flooded with raw fuel actually coming out of 3&4 but not out of 1&2. I have tried a couple of different carburetors and even a different manifold but nothing seems to make any difference. 

I guess that it is time to quit for the weekend.


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## Shopgeezer (Jan 5, 2020)

Sounds like your fuel is not being atomized by the carb. I wonder about pre-heating. We have engines on the farm that benefit greatly from a touch with the tiger torch. The Deutz diesels won’t start without it.


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## dnalot (Jan 5, 2020)

I decided the Snow engine is a failed design and not worth wasting my time on. Getting over it and moving on. Still looks nice on the shelf but will probably move it as the working engines are offended by sharing the shelf with a looser. 

Mark T


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## Gordon (Jan 6, 2020)

I agree that the carburetor is likely the problem. I am wondering about putting two carburetors on it. One carburetor on #1/#2 and another on #3/#4. I think that the long intake manifold is a problem. Fuel is atomized at the carburetor but reforms to a liquid before it reaches the cylinders. The two carburetors would not have to matched exactly in order to run since the cylinders fire in sequence.


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## Gordon (Jan 6, 2020)

dnalot said:


> I decided the Snow engine is a failed design and not worth wasting my time on. Getting over it and moving on. Still looks nice on the shelf but will probably move it as the working engines are offended by sharing the shelf with a looser.
> 
> Mark T


I seem to be drawn to failed designs. I worked for way too long on my Atkinson Differential before I decided that it was a very marginal design and it was time to stop beating a dead horse. Unfortunately working full size engines do not always scale down successfully. It is true that for most of our model engines we just want them to run successfully but not actually power anything so we accept just looking and sounding nice.


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## Rustkolector (Jan 6, 2020)

Gordon,

I posted a while ago here about my problems with the Snow and in particular an issue I took with the intake manifold design. It quickly gets very cold upon engine start. Many engines would run a short time and then stop. Mine started doing this later on, but not initially. The cold impedes good fuel distribution and likely causes fuel and moisture condensation as well. I found a significant improvement by building a flat log type intake manifold. It proved even better when I jacketed this manifold and forced return coolant through it.

Last year at this time my Snow was running very well. It ran without stopping at 400 RPM as long as it was getting fuel, and combustion had improved to the point where the gasoline/oil mix was burning with a visible blue color. The only drawback was increased carbon inside the engine. The jacketed intake manifold absorbed significant engine heat allowing long engine runs with only a small coolant reservoir system. I was very pleased with the engine. However, the pleasure did not last long. I soon discovered significant cylinder and piston rod corrosion. I blame my own careless operation and ignorance of 12L14 cylinder material for this problem. Short runs create significant moisture inside the cylinders. You cannot let it remain on confined 12L14 surfaces after shutdown even a minute, especially if the engine is burning the fuel completely. If the exhaust is slobbering wet all the time this condition is probably not as bad. I believe this combustion created moisture can cleared by spinning the engine over (fuel ON, ignition OFF) immediately after every engine shutdown.

So far, I attribute the improved running of my Snow engine mostly to two specific improvements. First the coolant heated jacketed log type intake manifold. It keeps the manifold very warm to the touch right up to the bottom of the carb. I used a small 3 mm throat RC carb. The second improvement was a different cam lobe profile. The cam was changed to a 46⁰ profile. This allowed for  ~220⁰+ exhaust duration. However, the single cam lobe Snow feature required increasing the intake valve lash significantly to get a more reasonable 190⁰ duration on the intake valve. For what its worth, I once ran across an old engine book from 1906 on Google books that indicated Snow (Worthington) had recently (1906) improved the poor light load operation of their tandem double acting gas engines. Unfortunately, the book did not say just how they did it.   

In my rebuild I am reusing the cleaned up original cylinders (with better maintenance) and replacing the piston rods with stainless steel. The new piston set screws will be 6-32 half dog type. I also have replaced the piston rod connector with a split type and cutting the piston rod connector reliefs .032” deep to allow use of a temporary Delrin clip type insert to protect the oil seal during assembly.
Jeff


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## oldengineguy (Jan 6, 2020)

Hello All:   Re Snow Engine   After seeing the real thing at Coolspring , I knew  I'd have to build this engine if only for show maybe not a runner.  I saw one running at NAMES 2019  that had different  manifolding and a radiator ,but can't remember the fellows name. I have had moderate success with other engines but compression loss is always a concern. After reading this thread it seems there may be hope for a runner . I like the heated manifold idea and Loctite on the piston rod/ piston. I'm a long way from that point yet  but am only a few parts away from a stack of cylinders and crank assembly  which is the point where I find out  whether a piston rod will slide or whether I have taken on more than I am able to do with my machines and skills. Regards  Colin


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## mfrick (Jan 7, 2020)

So When I built my Snow engine I used a spit coupler threaded with LH/RH threads this allowed to adjust the stroke of each piston, the nut has two allen head screws to lock once the stroke is set. The piston rods are 1045 chrome hydraulic piston rod material.  Cylinder liners are cast iron with alu pistons.  I did change the intake manifold making it a straight manifold and this did improve the running of the engine.   Engine runs great for 8 to 10 hours then it carbons up due to the fact that I used mixed gas. I need to play with the mixture and see if I can cut down on the amount of oil used. 

Mike


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## Gordon (Jan 7, 2020)

Obviously I am missing something. I cannot get my engine to run on it's own for more than a few seconds. I think the compression is the problem but I certainly cannot isolate the problem. I have a fitting which permits me to put compressed air into the cylinder through the spark plug hole and I can pressurize it to 30-40 psi and there are no or at least very minimal leaks. I can put a pressure gauge in the spark plug hole and turn the engine over by hand and the gauge jumps up to about 10 psi but immediately drops to 0. If I turn it over with my drill it jumps up to about 40 psi but drops right back to 0. On the other hand turning it over by hand I do not feel any appreciable bounce back. If I put my finger over the spark plug hole and turn it over by hand I can feel some pressure on the compression stroke and it seems to hold vacuum for a couple of seconds on the intake stroke. I had the engine running a couple of years ago until I decided to "improve" it recently. 

I have 12L14 cylinder liner, aluminum pistons and drill rod connecting rod but I have not noticed any rusting or corrosion. I use Coleman fuel with a shot of Marvel Mystery oil which is the same as I use in all of my engines.


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## mfrick (Jan 7, 2020)

Hi Jeff
Could you post a drawing of your new cam profile.

Mike


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## Rustkolector (Jan 7, 2020)

Gordon,

If you don’t have a pressure gauge that holds the highest reading, it is normal to see the compression pressure or vacuum bleed off rather quickly through the ring gaps. No flywheel bounce back is puzzling unless your engine hasn’t been run much. If you crank your engine with a portable drill driver and you can hear the compression strokes in the sound of the drill motor I would say the problem is not compression.

Have you documented your valve timing? I have gathered some relative valve timing information on one currently running 400 hp Snow engine and it is pretty strange. I have told two other builders about the 46⁰ cam profile and this single change produced a running engine in both cases (see link below). I don’t have a drawing of this cam lobe, but see item #46 in the original drawings and reproduce it with a 46⁰ angle instead of the original 58⁰ angle. It produces longer duration. Install the cams and then adjust the exhaust valve lash at about .002-.003”” and then, using a dial indicator on the valve spring retainer, set the exhaust valve opening (EO) to about 40-45⁰ BBDC and exhaust close (EC) at TDC. Then adjust (by opening) intake valve lash to get IO at about  5⁰ ATDC and IC at about 10-15⁰ ABDC. It should run better provided everything else is good. This is not an orthodox valve adjustment means, but with only one cam lobe you have to improvise. The wide valve lash hasn’t presented and issues or wear on my engine.

Jeff

http://www.modelenginemaker.com/index.php/topic,4060.630.html (go to reply 632)


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## Gordon (Jan 8, 2020)

Rustkolector said:


> Gordon,
> 
> If you don’t have a pressure gauge that holds the highest reading, it is normal to see the compression pressure or vacuum bleed off rather quickly through the ring gaps. No flywheel bounce back is puzzling unless your engine hasn’t been run much. If you crank your engine with a portable drill driver and you can hear the compression strokes in the sound of the drill motor I would say the problem is not compression.
> 
> ...


Thanks. I have not been watching valve timing too closely. I will try your settings to see what happens. Last night just before I quit I noticed that at least on #4 I was getting a puff back through the intake which is obviously exhausting the intake manifold just prior to the intake stroke so at least part of the intake stroke is used to refill the manifold. This tells me that I am opening the intake valve BTDC while it is still in the exhaust cycle. I had run across your 46° cam on another post and I have made 46° cams. Generally valve timing is not as critical as it is on this engine but as you say you are using the same cam for both intake and exhaust so things become a compromise. 

A continuing problem is the set screws come loose as the engine runs. I like the idea of at least making the rod coupling with RH and LH threads. I have already made the set screws in the cams 6-32 instead of 2-56. Trying to tighten a 2-56 with a .050 hex just does not provide enough torque to hold. I have also put a coupling in the valve shaft which makes the adjustment of the relationship between ignition and valve timing easier.

Hopefully I will get time soon to get back and try some things. My wife seems to think that replacing the GFI receptacle in her bathroom just because it trips even with no load is more important than working in the shop. Sometimes wives have no concept of priorities.

Gordon


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## awake (Jan 8, 2020)

> I don’t have a drawing of this cam lobe, but see item #46 in the original drawings and reproduce it with a 46⁰ angle instead of the original 58⁰ angle. It produces longer duration.



Newbie here - can someone help me to understand what it means to talk about a 58° angle or 46° angle (or whatever angle) cam? I'm particularly confused because my first thought is that this angle is the included angle of the flanks of the cam (if that's even the right word - the flats or slightly rounded part that leads up to the lobe). But if that is the case, wouldn't a smaller angle result in *less* duration rather than more? I think I am not understanding correctly ... help!


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## Gordon (Jan 8, 2020)

awake said:


> Newbie here - can someone help me to understand what it means to talk about a 58° angle or 46° angle (or whatever angle) cam? I'm particularly confused because my first thought is that this angle is the included angle of the flanks of the cam (if that's even the right word - the flats or slightly rounded part that leads up to the lobe). But if that is the case, wouldn't a smaller angle result in *less* duration rather than more? I think I am not understanding correctly ... help!



per my as I go along sketches


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## Rustkolector (Jan 8, 2020)

Gordon,

Set screws are a problem indeed. I ran across a this set screw tightening recommendation: *To tighten new, standard, alloy, cup point set screws, install an allen wrench with the short end in the socket, long end in your hand, and tighten until the wrench bends or twists about 30° (1 hour on a clock face). Then the set screw is as tight as it should be.* The key word is “new”. Don’t put used set screws in a final assembly, and use black alloy and not SS. Always dress up the wrench end if any rounding apperars. I am using half dog point set screws on my pistons. In theory they should help. I had considerable trouble with the connector set screws loosening, but none of the others. 


Mike’s idea on the piston rod connector is a very good one. Piston position is difficult to equalize, but can be done close enough. I was more concerned with damage to shaft seals during assembly. I chose the split type I saw on another Snow engine builders engine. I was able to make a temporary and simple split clip Delrin bushing that snaps in  the shaft connector relief. This allows the shaft connector relief to smoothly glide past the seal with no forcing.

Jeff


http://www.safetysocket.com/sites/www.safetysocket.com/files/parts/bd/Products/setscrewtorque.htm


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## mfrick (Jan 8, 2020)

Hello Jeff
Thanks for the SnowCam  drawing.  I will try this out on my engine and let you know how it works out.

Mike


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## awake (Jan 8, 2020)

Gordon, that sketch is very helpful. I realize now that I was "defining" the angle correctly ... I just wasn't processing the results correctly in my head.

I should have realized - the one time I have attempted to cut a cam thus far, the same sort of confusion caused me to cut it wrong. I was thinking it was simple - a 62.5° degree cam was called for, so I would need to make cuts while rotating the dividing head by (360-62.5) = 297.5°. Ah, no. I did finally get it right, but I am still not quite sure how to turn it into a formula ...


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## Gordon (Jan 8, 2020)

Rustkolector said:


> Gordon,
> 
> If you don’t have a pressure gauge that holds the highest reading, it is normal to see the compression pressure or vacuum bleed off rather quickly through the ring gaps. No flywheel bounce back is puzzling unless your engine hasn’t been run much. If you crank your engine with a portable drill driver and you can hear the compression strokes in the sound of the drill motor I would say the problem is not compression.
> 
> ...


I have the engine somewhat running, at least I did until the rod coupling came loose again. There is one thing which does not seem right or at least I do not understand it on the valve timing. I have flats milled on the valve connector rod at 90°. That is if #1=0°, #2=90°, #3=180°, #4=270°. It would seem like once one cylinder is set the others should be also set but there seems to be quite a bit of variation from one cylinder to the next. If  #1 is set for intake close at 10-15 ABDC #2 closes at 10 BTDC. I have tried to compensate by adjusting for more or less valve lash gap but that is not giving me 190° open on each cylinder. Should not the valves be at a fixed 90° position? Any idea what is causing the variation?
Gordon


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## Rustkolector (Jan 8, 2020)

Gordon,
Sorry, no idea of the cause of the variation. However, the camshaft  flats at 90⁰ sounds like a good idea and probably would work on a shorter larger diameter camshaft, but I found precise cam lobe adjustments on this long small diameter camshaft to be very sensitive. You will still have to fine adjust each one. If you could clock the flats to the easy-to-set EO location, it might prove helpful. Use a degree wheel on the crankshaft, set the #1 cylinder at 40-45⁰ BBDC on the power stroke and back the cam lobe up against the exhaust lever roller and snug one set screw. Fine adjust till you get EC at, or just after TDC. Go to the remaining cylinders adjusting for the EO at the same setting. This is a very slow speed engine so any valve overlap is likely not beneficial. After setting the exhaust valves, go back and adjust the intake valves using the valve lash. There may be some slight variation in the possible exhaust settings, but usually all will be close to the desired setting.  You probably won't get them all to the same setting, but close should be good enough. Replace all set screws with new and tighten. Take your time.  

Jeff


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## Gordon (Jan 9, 2020)

Rustkolector said:


> Gordon,
> Sorry, no idea of the cause of the variation. However, the camshaft  flats at 90⁰ sounds like a good idea and probably would work on a shorter larger diameter camshaft, but I found precise cam lobe adjustments on this long small diameter camshaft to be very sensitive. You will still have to fine adjust each one. If you could clock the flats to the easy-to-set EO location, it might prove helpful. Use a degree wheel on the crankshaft, set the #1 cylinder at 40-45⁰ BBDC on the power stroke and back the cam lobe up against the exhaust lever roller and snug one set screw. Fine adjust till you get EC at, or just after TDC. Go to the remaining cylinders adjusting for the EO at the same setting. This is a very slow speed engine so any valve overlap is likely not beneficial. After setting the exhaust valves, go back and adjust the intake valves using the valve lash. There may be some slight variation in the possible exhaust settings, but usually all will be close to the desired setting.  You probably won't get them all to the same setting, but close should be good enough. Replace all set screws with new and tighten. Take your time.
> 
> Jeff


Jeff: Thank you very much. Your input has been very helpful. I am sure that I am now on the right track. I am presently waiting for a couple of things to continue but I am now confident that I will get it running. Valve timing is the answer. The extended running will come later.

This and other on line groups are very helpful. Frequently we are too close to the problem to see even obvious solution. The internet is not all bad. There are some real advantages.

Gordon


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## Gordon (Jan 16, 2020)

Latest observations on the Snow: I think that the most important aspect of valve timing is to be sure to start the intake stroke after bottom dead center. If the intake is started before bottom dead center a puff of exhaust blows out through the manifold and exhausts the manifold chamber which then must be refilled in order to start filling the manifold with a combustible mix. This is my theory and I am sticking with it until proven wrong but once I made sure that the intake started ATBC I could get the engine to start.

As suggested I have made a rod coupling with RH & LH threads to adjust the stroke and prevent the loosening of the set screws and uncoupling of the rods. I then put the assembly together with the #1 and#4 heads removed and discovered that as built the #3 piston extends into the combustion chamber by 1/8" and #4 piston is 1/8" short. I then did a CAD layout and confirmed this. In order to get the correct position there is a 5/16" gap between the two piston rods. Each rod should be about 1/8" longer. I am not sure how much this affects the running but I am sure that it it does not help.

Gordon

I just back into the CAD drawing and checking parts and I have found that I had cut the piston retaining groove from the wrong end. However it just meant that the piston was too far in the other direction. Both piston rods should be shortened by .07 in order to center in the cylinders. Back to the lathe to remake the piston rods. By my calculations and CAD drawing the groove on each rod should be 3.59 from the end, not 3.66. Now if I just did not screw up again. That is a real possibility with me lately.


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## Gordon (Jan 23, 2020)

Does anyone have a picture or drawing or description of how Doug Kelly utilized a point ignition on his original Snow? He used the electronic ignition later. The electronic ignition is kind of fussy and I was thinking that perhaps the point ignition would be less fussy. I am not sure where and how to place the four lobe cam without it being unsightly. 

Gordon


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## Rustkolector (Jan 24, 2020)

Gordon,
At the time Doug, and many others, built the Snow engine a company in FL called MJN Fabrication was selling all the Bruce Satra designed ignition components including the distributors. Many of us bought the distributor bases with a set of points installed. The four lobe ignition cam is an integral part of the distributor rotor shaft and operated the MJN installed points. A lot of builders used the points with any number of transistor ignition systems and a separate coil and battery. MJN closed up their operations about the time the more compact CDI ignition was introduced. Most everyone now seems to prefer the CDI systems using a Hall magnetic sensor in the flywheel or distributor base. They are as simple and compact as it gets. 
Jeff


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## Gordon (Jan 24, 2020)

Rustkolector said:


> Gordon,
> At the time Doug, and many others, built the Snow engine a company in FL called MJN Fabrication was selling all the Bruce Satra designed ignition components including the distributors. Many of us bought the distributor bases with a set of points installed. The four lobe ignition cam is an integral part of the distributor rotor shaft and operated the MJN installed points. A lot of builders used the points with any number of transistor ignition systems and a separate coil and battery. MJN closed up their operations about the time the more compact CDI ignition was introduced. Most everyone now seems to prefer the CDI systems using a Hall magnetic sensor in the flywheel or distributor base. They are as simple and compact as it gets.
> Jeff


I have the S&S distributor. I am not sure what the problem is but I have burned out the transistor on a TIM 6 twice now. I have it running using the S&S ignition module. I was just thinking that a straight forward point ignition would be simpler. If it requires making a new distributor with internal points it certainly is not easier. I guess I will just stick with the existing setup. Thanks. 
Gordon


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## Gordon (Feb 2, 2020)

Update: I just made a new intake manifold, straight line 7/32 dia tube. Due to a screw up on tapping the carb mount block I ended up using another existing single throat non throttled carb and the engine starts and runs well. I do not have the coolant system reinstalled yet so I cannot run it for more than about 4-5 minutes before it starts to get too hot. I figured that coolant was not a priority until I could get it running consistently.


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## Rustkolector (Feb 2, 2020)

Persistence pays off. Congratulations!
Jeff


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## Rustkolector (Feb 29, 2020)

Gordon,
How are your Snow modifications coming?
Jeff


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## Gordon (Feb 29, 2020)

Rustkolector said:


> Gordon,
> How are your Snow modifications coming?
> Jeff


I have it running but it keeps getting out of adjustment. I cannot keep the set screws tight enough. At this point it is no longer my problem. Due to some strange circumstances I ended up selling it. I was working with a guy to sell him one of my engines and the next thing I knew he bought 15 of my engines. I have been thinking about thinning out my stock so that my kids did not have to try to figure out what to do with them and the whole thing went down a lot quicker than I anticipated. That is good. I have been just working on previous engines to tweak them because I did not want to add to the problem. Now I will probably take on another larger project which hopefully will be year long project. My kids are also glad.


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## burn0170 (Aug 25, 2020)

Rustkolector - Do you have any pictures or details of how you did the updated intake manifold?  We are building the snow now and will be using your suggested updates to hopefully lessen the frustration in getting it running.


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## Rustkolector (Aug 25, 2020)

The intake manifold was made by soldering two 3/8” x 3/16” rectangular cross section brass tubes back to back. See photo of the open end cross section before closing it up. The center carburetor cross section sketch shows the coolant water path at the carburetor. I suggest you put a drain fitting at the bottom and end of the outer fuel manifold to be able occassionally to remove any collected fuel and oil.

Also, see other HMEM forum thread on the same subject My Improved Snow Engine


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## burn0170 (Mar 24, 2021)

Rustkolector - We are assembling our Snow, and I noticed on one of your posts that you mentioned that you pinned the pistons, or that you were thinking of switching to half dog set screws.  What did you use for pins?  Spring pins, taper pins, or ??  I was thinking about using green loctite, but I also like your idea of pins.  Any advice on securing the pistons is appreciated.  We aren't to the point of starting it quite yet, but I assume once we get the pistons centered in the bores, we should never have to remove them from the piston rods?


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## Gordon (Mar 24, 2021)

burn0170 said:


> Rustkolector - We are assembling our Snow, and I noticed on one of your posts that you mentioned that you pinned the pistons, or that you were thinking of switching to half dog set screws.  What did you use for pins?  Spring pins, taper pins, or ??  I was thinking about using green loctite, but I also like your idea of pins.  Any advice on securing the pistons is appreciated.  We aren't to the point of starting it quite yet, but I assume once we get the pistons centered in the bores, we should never have to remove them from the piston rods?


They probably will have to be removed at some point. You are probably going to have to replace the seals or the head gasket.


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## burn0170 (Mar 24, 2021)

Gordon said:


> They probably will have to be removed at some point. You are probably going to have to replace the seals or the head gasket.


Thanks Gordon, just to clarify, we wouldnt need to remove the piston from the rod to replace seals or gaskets, right?  I modeled my center coupling after Rustkolector's design and that worked great so far.


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## Rustkolector (Mar 24, 2021)

burn0170
Most Snow builders have encountered set screw loosening at the center rod connector and sometimes the pistons. Most of that comes from tired set screws that are worn from assembly and reassembly. The heavy recip masses in the Snow really stress all the piston rod assembly set screws. For the center connector you can thread the rod ends and connector. I chose to make my rod ends with full end to end contact between each other and use a clamp type connector. One of my other Snow threads shows a sketch of the clamp connector. The clamp type allows for easy disassembly. If you use this method you will need to also make a small single cut split delrin filler piece for the rod clamp shaft relief to prevent damage to the lip seals when assembling.

The pistons are not as hard on the set screws as the center rod connector but there is a good chance one of them might come loose. On my rebuild I also installed a spring pin (size ?) to retain each piston after finalizing the piston positions. In my experience the pistons do not have to be precisely positioned, just very close. There maybe a tiny usable adjustment allowance left in the crankshaft block position that can help.

CAUTION: I have enjoyed my Snow engine and it had accumulated lots of both short and long run time cycles. I never paid much attention to how I left the engine after shutting it down. As a result I noted that upon disassembly my cylinders and piston rods (drill rod) showed significant corrosion had taken place although the engine was still running fine. Upon rebuild I decided to use TGP stainless steel piston rods. I have also adopted an engine shutdown procedure to mitigate cylinder bore damage from combustion moisture (which can be significant).  I now spin the Snow engine over about 20-30 revs with ignition OFF, throttle OPEN, and fuel ON to rid any residual combustion moisture and hopefully lubricate the cylinder.  
Jeff


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## burn0170 (Mar 24, 2021)

Thanks Jeff, that is very helpful.  I've reviewed your other posts have incorporated all of your findings (center clamp connector, stainless piston rod, new cam design, intake manifold, etc).  I'm hoping to learn from your experience and have a good running engine without too much frustration.  I really appreciate everyones help!


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## burn0170 (Mar 31, 2021)

I just wanted to drop a quick note and say thank you to Jeff, Gordon, and the others that have documented their experiences with the Snow engine, we started ours last night for the first time.  Your input and experience really helped move our project along and help us avoid issues.  Once we get it tuned in, I'll post some pics/videos.  Thanks again.


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