Chain Drive Apposed Piston

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johnmcc69

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That's very interesting, similar to the Atkinson.

I would be interested in any more pic's or drawings of what you have made.

That's an unusual engine & a great runner! You did a fantastic job on it!

John
 

Nerd1000

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A four stroke opposed piston engine is quite the oddball! Very cool, I have thought about how this sort of thing might be done but haven't gone further than that.
 
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It was a long road to get to this finish line with several different design changes. I tried using a cog belt but in order to stop the belt from jumping a tooth I had to have the belt quite tight. This caused too much drag on the engine as it would fire but not run on its own. Maybe a different belt with deeper teeth would have helped.
I also tried aluminum gears and as it did run the noise level was way too high. If the gears were inside a housing to muffle the sound it may have been acceptable but it would have been a project in itself.

I will post a few pictures.

IMG_0979.JPG
IMG_0992.JPG
IMG_1215.JPG
IMG_1214.JPG

I do have more pictures and a couple of drawings if there is a specific area you would like to see let me know.

Thank you all for the kind words and likes.

Ray
 
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The spark plug comes up from the bottom awake.

I don't make many drawings but when there is a possibility of interference I will plot it out.
This is one I did when I reduced the stroke to 1" per piston. I also reduced the piston diameter to 0.75 in hopes I could find a balance between engine power, tooth jumping, and belt tension. I was not successful so went to the chain drive instead. If I had used the chain drive originally I believe I could have stayed with the 3" stroke and a 1" diameter piston.
Mounting Plate.jpg
In order to keep the compression ratio up I had to make the pistons enter the original 1"combustion chamber 0.090 on each. If I remember correctly I am around 5.2 to 1 now.

Gear train.jpg
The gears were cut 16DP so if you need any I have some left over.

Thanks for looking
Ray
 

Nerd1000

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It was a long road to get to this finish line with several different design changes. I tried using a cog belt but in order to stop the belt from jumping a tooth I had to have the belt quite tight. This caused too much drag on the engine as it would fire but not run on its own. Maybe a different belt with deeper teeth would have helped.
I also tried aluminum gears and as it did run the noise level was way too high. If the gears were inside a housing to muffle the sound it may have been acceptable but it would have been a project in itself.

I will post a few pictures.

View attachment 143715
View attachment 143717
View attachment 143718
View attachment 143719

I do have more pictures and a couple of drawings if there is a specific area you would like to see let me know.

Thank you all for the kind words and likes.

Ray
I think a gear (or chain!) housing is a perfect job for a 3d printer. Print in PETG or nylon and you can even have an oil bath for all the moving parts.
 

vederstein

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Very Cool!

The chain appears to make quite a racket. Is it very loud in real life?

...Ved.
 
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The chain makes a swooshing sound that is not objectionable. The engine is generally louder than a hit miss engine as there is more going on but compareable to my twin with an exposed cam.

Thank you for the question
Ray
 

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