- Joined
- Feb 2, 2014
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- 1,217
This is my ninth internal combustion engine I have built and most have taken no more than a couple of months to complete but this one has been a long road as I started in July of last year. During that time I had put it up on the shelf a couple of times to do some more thinking when I ran into a road block . Most of my engines are of my own design from bar stock so the final product is seldom the same as I first envisioned it.
I saw a similar model engine made by a German company I believe and thought it would make a nice project. It ran on LP gas or similar gas and used a complicated rotary valve setup. I now also understand that Cummings is developing a similar engine that is two stroke and uses a blower some how to purge the combustion chamber and add fresh fuel mix.
My original design was to use a coged belt arrangement with two crankshafts turning the cam shaft / output shaft.
The combined stroke was 3" and the piston diameter was 1". The pistons would come together in the center where the intake and the exhaust vales and the spark plug was located.
The belt chosen was a Gates 15mm wide HTD power grip belt with the corresponding gears for a two to one ratio.
When I was testing this arrangement I found that the belt had a tendency to jump a tooth on one of the gears when it fired. I kept increasing the belt tension until it no longer jumped a tooth but now the engine would actually jump off the table when it fired even though I was holding it with my free hand. The firing actually caused one of the rollers to bend so time for a design change.
I dropped the stroke down to 2" instead of 3"and tried again with sturdier rollers. The engine would fire consistently but not run because I still had to have the belt rather tight and that created considerable drag. So now another design change.
The belt is gone and now gear drive. This did reduce the engine drag considerably and I was able to get the engine to run but as a witness can attend "It sounds like a freight train just outside the door". The noise level was way too high and completely unacceptable probably because I had cut my own gears and they were not enclosed. Time for a design change.
I reduced the piston diameter to 3/4" in the hopes that the reduced power would allow me go back to the coged belt arrangement. I made some cast iron liners for the cylinders and reinstalled the belt pulleys. Well that didn't work as the belt would just jump a cog or if the belt was tightened it did not have enough power to run.
Time for another design change and here it is.
Yes it is a size 35 roller chain and with some minor modifications it runs.
As built 3/4" piston 2" stroke.
Thanks for looking
Ray
I saw a similar model engine made by a German company I believe and thought it would make a nice project. It ran on LP gas or similar gas and used a complicated rotary valve setup. I now also understand that Cummings is developing a similar engine that is two stroke and uses a blower some how to purge the combustion chamber and add fresh fuel mix.
My original design was to use a coged belt arrangement with two crankshafts turning the cam shaft / output shaft.
The combined stroke was 3" and the piston diameter was 1". The pistons would come together in the center where the intake and the exhaust vales and the spark plug was located.
The belt chosen was a Gates 15mm wide HTD power grip belt with the corresponding gears for a two to one ratio.
When I was testing this arrangement I found that the belt had a tendency to jump a tooth on one of the gears when it fired. I kept increasing the belt tension until it no longer jumped a tooth but now the engine would actually jump off the table when it fired even though I was holding it with my free hand. The firing actually caused one of the rollers to bend so time for a design change.
I dropped the stroke down to 2" instead of 3"and tried again with sturdier rollers. The engine would fire consistently but not run because I still had to have the belt rather tight and that created considerable drag. So now another design change.
The belt is gone and now gear drive. This did reduce the engine drag considerably and I was able to get the engine to run but as a witness can attend "It sounds like a freight train just outside the door". The noise level was way too high and completely unacceptable probably because I had cut my own gears and they were not enclosed. Time for a design change.
I reduced the piston diameter to 3/4" in the hopes that the reduced power would allow me go back to the coged belt arrangement. I made some cast iron liners for the cylinders and reinstalled the belt pulleys. Well that didn't work as the belt would just jump a cog or if the belt was tightened it did not have enough power to run.
Time for another design change and here it is.
Yes it is a size 35 roller chain and with some minor modifications it runs.
As built 3/4" piston 2" stroke.
Thanks for looking
Ray
