O-Rings as piston rings

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warmstrong1955
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Re: O-Rings as piston rings

Post by warmstrong1955 » Wed Jul 11, 2018 9:37 am

No doubt, that if you go outside of the recommended fit, you will have leakage problems.
And to Harold’s point, I agree. If you try to get an o-ring to the same friction ‘feel’ as a cast iron ring, it will probably be out of tolerence, and too loose of a fit.

I’d like to know how it turns out too!

Other Bill
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tornitore45
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Re: O-Rings as piston rings

Post by tornitore45 » Thu Jul 12, 2018 8:33 am

Will report, I am still far away from that part of the construction.
Mauro Gaetano
in Austin TX

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warmstrong1955
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Re: O-Rings as piston rings

Post by warmstrong1955 » Thu Jul 12, 2018 10:28 am

Oh sure.....keep us in suspense....

;)
:)
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steamin10
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Re: O-Rings as piston rings

Post by steamin10 » Tue Jul 17, 2018 1:00 am

Freind past used O-rings for a Tich. His solution was polished bores and two piece piston that could be adjusted on the rod for crush on the ring. This flies in the face of the way o rings are supposed to float, but it worked famously with little drag, once set up.
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tornitore45
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Re: O-Rings as piston rings

Post by tornitore45 » Tue Jul 17, 2018 5:39 am

used O-rings for a Tich.
Interesting, but

What is a Tich? Steam? OR IC?
Mauro Gaetano
in Austin TX

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NP317
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Re: O-Rings as piston rings

Post by NP317 » Tue Jul 17, 2018 9:41 am

"Tich" is a small 0-4-0 steam locomotive.
~RN

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GlennW
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Re: O-Rings as piston rings

Post by GlennW » Tue Jul 17, 2018 2:10 pm

tornitore45 wrote:
Tue Jul 17, 2018 5:39 am
used O-rings for a Tich.
Interesting, but

What is a Tich? Steam? OR IC?
I'm guessing that your Hoglet is internal combustion?
Hoglet.jpg
Glenn

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tornitore45
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Re: O-Rings as piston rings

Post by tornitore45 » Tue Jul 17, 2018 3:54 pm

The Hoglet is so called because is a V twin loosely inspired by the Harley Davidson engine.
Love the picture.
In Italy we call that a Porchetta once is stuffed and roasted.
Mauro Gaetano
in Austin TX

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GlennW
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Re: O-Rings as piston rings

Post by GlennW » Tue Jul 17, 2018 4:25 pm

Italy, what a great place!

Some day I'll make it back there.
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

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Re: O-Rings as piston rings

Post by Harold_V » Wed Jul 18, 2018 1:18 am

tornitore45 wrote:
Tue Jul 17, 2018 3:54 pm
The Hoglet is so called because is a V twin loosely inspired by the Harley Davidson engine.
Love the picture.
In Italy we call that a Porchetta once is stuffed and roasted.
And delicious! :-)

H
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warmstrong1955
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Re: O-Rings as piston rings

Post by warmstrong1955 » Wed Jul 18, 2018 11:11 am

Looks like potential carnitas to me, still on the hoof, speaking of delicious!
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tornitore45
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Re: O-Rings as piston rings

Post by tornitore45 » Wed Sep 12, 2018 2:45 pm

I used this calculator and adjust the numbers to have just over the minimum recommended ring radial compression, I settled for 12% http://www.applerubber.com/oring-gland-calculator/

It turns out the number match what Glenn W posted.
The bore is mirror finish and a funny thing I noticed.
The static friction is much higher than the the moving friction. That is a known fact but usually the difference is not too great.
I put a temporary crank on the V twin and it turn fairly smooth.

Thanks to all that helped.
Mauro Gaetano
in Austin TX

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