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Author Topic: Jin's R18 Benz engine detail  (Read 199 times)

rodnoc

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Jin's R18 Benz engine detail
« on: January 31, 2023, 01:09:52 am »
I suspect that you guys might like to see what Jin's 1886 Benz engine looks like.

It is very nicely made.


Starting with the guts of the intake slide-valve.

The original engine used spring pressure to seal the slide.  Jin uses o-rings.


The intake slide






The above part flipped.



The exhaust valve.


The exhaust-valve head visible in the recess, and the unusual piston 'crown'.



Tiny spark plug. It needs to be removed to get the piston out.



To get a look at the piston, I removed the rod cap....



...and pulled the piston down far enough to push out the wrist pin. Then pushed the piston out the top.









End

komet163b

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Re: Jin's R18 Benz engine detail
« Reply #1 on: January 31, 2023, 11:41:37 am »
  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

Steamloco

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Re: Jin's R18 Benz engine detail
« Reply #2 on: February 01, 2023, 09:59:18 am »
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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rodnoc

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Re: Jin's R18 Benz engine detail
« Reply #3 on: February 01, 2023, 12:31:12 pm »
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.

rodnoc

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Re: Jin's R18 Benz engine detail
« Reply #4 on: February 02, 2023, 02:16:52 pm »
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.



RobA

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Re: Jin's R18 Benz engine detail
« Reply #5 on: February 07, 2023, 04:33:16 pm »
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!

Jim

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Re: Jin's R18 Benz engine detail
« Reply #6 on: February 07, 2023, 05:07:35 pm »
Thanks for the photos.
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rodnoc

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Re: Jin's R18 Benz engine detail
« Reply #7 on: February 07, 2023, 08:22:59 pm »
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.

Fullraceflathead

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Re: Jin's R18 Benz engine detail
« Reply #8 on: February 11, 2023, 03:49:51 pm »
Excellent detailed photos thank you very much!!!

gamma13r

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Re: Jin's R18 Benz engine detail
« Reply #9 on: March 09, 2023, 04:39:57 pm »
Huge thanks for your post and sharing all your pics, rodnoc.

My R18 just arrived the other day, its such a sweet little engine;
I am beyond impressed w it.

 

Tom Jensen Jr. 1936-2023