Author Topic: piston oil rings  (Read 829 times)

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Offline AdminPete

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piston oil rings
« on: November 26, 2008, 06:02:30 pm »
I recently bought on oversized piston kit for my BSA C11G 1954, and i'm not sure which way up the oil ring goes?
One side is square, and the other has a very small taper.
Has anyone had experience with such a thing, and can let me know?
Thanks
Tony
 


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From: floydpiper Sent: 13/01/2007 15:59
Hi,

I have the Hepolite instructions (from a box of BSA rings) right in front of me. It shows a photo of a tapered ring. The ''taper'' (thinner side) is facing UP. The instructions next to the photo, says:

''Taper or word 'TOP' towards piston crown.'

That would mean 'UP'.

Best of luck to you.

Sincerely,
Gregg
 

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From: milser78 Sent: 14/01/2007 11:35
Thanks Gregg,
That has helped heaps. I have seen some generic sites that seem to have bevel facing up, just wanted to confirm it with someone in the know. Thanks again
 
Tony
 

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From: chancho196 Sent: 14/01/2007 13:16
Yep, absolutely right. If I remember from my college days, it is to allow oil to bypass the ring as it goes upwards and scrape it down the bore on it's way down.
 
Cheers, Ben.
 

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From: floydpiper Sent: 15/01/2007 22:08
Hi Tony,

You're very welcome. I know the feeling. It's not like you can just ''flip'' it over after you find out you did it wrong.

I also know the feeling of knowing with certainty that you're doing something (this important) the right way. It's a big feeling of relief.

Best of luck to you.

Sincerely,
Gregg
 

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From: floydpiper Sent: 15/01/2007 22:15
Hi Ben,

(Quote): "If I remember from my college days, it is to allow oil to bypass the ring as it goes upwards and scrape it down the bore on it's way down."

I was thinking (as I wrote the correct instructions down for Tony), that I would have thought it would face the other way, because it would seem to me that if oil can get past it on the way up, then so can the COMPRESSION. It's kind of weird that it works that way.

I can only assume that it's designed so that ''X'' amount of compression is intended to get past it, so as to accomplish exactly what you said it does, which is to get that oil back down inside the motor.

So, I guess it does make sense after all.

:)
Gregg 
 

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From: chancho196 Sent: 16/01/2007 23:20
I might go and check to be sure now but the idea is, the compression rings will do their job and the oil control ring will try and limit the oil left on the bore. The oil ring will allow oil to bypass it on it's way up, the oil will then go into the gaps in the ring and be forced into the inside of the piston. On it's way back down, it should scrape the remaining oil off the bore with the square edge (lower).