Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines
The Regular Stuff: Chat, Buy, Sell, Off Topic, etc. => General Discussion - Scale Model Gas Engines - Hit & Miss - Throttle Governed - Non-Compression – etc => Topic started by: rodnoc on January 31, 2023, 01:09:52 am
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I suspect that you guys might like to see what Jin's 1886 Benz engine looks like.
It is very nicely made.
(https://i.ibb.co/sFkPL4K/A-IMG-1981.jpg)
Starting with the guts of the intake slide-valve.
The original engine used spring pressure to seal the slide. Jin uses o-rings.
(https://i.ibb.co/mHr47LS/a-IMG-1979.jpg)
The intake slide
(https://i.ibb.co/tLJXsD9/b-IMG-1977.jpg)
(https://i.ibb.co/ypr3vk5/c-IMG-1975.jpg)
The above part flipped.
(https://i.ibb.co/zSRV5qZ/d-IMG-1976.jpg)
The exhaust valve.
(https://i.ibb.co/1qkYBfQ/e-IMG-1982.jpg)
The exhaust-valve head visible in the recess, and the unusual piston 'crown'.
(https://i.ibb.co/g3yGgJS/f-IMG-1983.jpg)
Tiny spark plug. It needs to be removed to get the piston out.
(https://i.ibb.co/g3PwTZg/g-IMG-1987.jpg)
To get a look at the piston, I removed the rod cap....
(https://i.ibb.co/TH6tN1M/h-IMG-1984.jpg)
...and pulled the piston down far enough to push out the wrist pin. Then pushed the piston out the top.
(https://i.ibb.co/c8Y1r5J/i-IMG-1986.jpg)
(https://i.ibb.co/vDxZcyZ/j-IMG-1989.jpg)
(https://i.ibb.co/qkzg5ST/k-IMG-1990.jpg)
End
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Verrrry cool. Nice sequence of pix. Makes me want
to buy one - and I don't collect IC engines!
Does the piston match the original or is made to
such a strange shape for another reason?
Have lots of fun,
Wayne
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Since the head is flat, the piston "crown" area becomes the combustion chamber. Don't know if that is related to the original engine.
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Searching for data about the original engine is becoming a black hole for time. What I've seen of the Benz 1886 patent just shows some detail about the car. There are apparently a few full-scale operational copies of the car and it's engine in existence, so there must be some engineering drawings somewhere. I'm still looking.
The original engine had a compression ratio of 2.7:1 (not much) and made about 3/4 hp at 400 rpm.
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I missed a photo in the pile. Better late than never.
The exhaust valve assembly. This also shows a closer view of refinement to the head which is a casting with surface roughness. To ensure a good seal with the head gasket I smoothed it with 600 wet/dry on a surface plate.
(https://i.ibb.co/py1TW3z/IMG-1995.jpg)
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Is the piston pin secured in some way? Due to the unique vertical axes of rotation of this engine, the pin would have a tendancy to fall down and rub against the cylinder wall.
Beautiful and well done engine!
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Thanks for the photos.
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Is the piston pin secured in some way?
No, and it is free enough to move. During reassembly I sliced two wafers from an old o-ring so each end of the pin had a buffer. The wafers are thin so they don't create any drag. I've done this to several engines and it seems to work fine.
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Excellent detailed photos thank you very much!!!
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Huge thanks for your post and sharing all your pics, rodnoc.
My R18 just arrived the other day, it’s such a sweet little engine;
I am beyond impressed w’ it.