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Re: single compression ring piston

Posted: Tue Feb 11, 2020 10:04 pm
by LSP
engineguyBill wrote: Tue Feb 11, 2020 8:51 pm
LSP wrote: Tue Feb 11, 2020 12:18 pm
engineguyBill wrote: Mon Feb 10, 2020 9:46 pm

I don't want my second ring to EVER try to control any amount of combustion pressure, that's why every motor I build gets more second ring and top oil rail gap than the top ring does, some A LOT more.
You will be able to sleep peacefully knowing that your second rings will help control any combustion pressure that is getting past the top ring. And some combustion pressure WILL get past the top ring via ring end gap, piston rock, cross-hatch pattern, etc., etc. Engineering nomenclature, including manufacturing prints still refer to piston rings as top compression ring, second compression ring/oil scraper and oil ring assembly. The ability of the accumulator groove to function according to design is made possible by the second ring's ability to control combustion pressure.
No, the 2nd ring isn't doing any of that in anything I build. I at least double, and sometimes triple the 2nd ring and top oil rail end gaps compared to what the top ring end gap is in some cases. I don't put any accumulator grooves in 2nd ring lands, why would I want to weaken the land that all the cylinder pressure is leaning on?

Re: single compression ring piston

Posted: Wed Feb 12, 2020 5:06 pm
by jsachs1
Back in the late 60's, I ran a AA/GS Anglia. 460" 671 Blown, B. B. Chev. with Venolia 2 ring pistons. Never any oiling problems at all.
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Re: single compression ring piston

Posted: Wed Feb 12, 2020 8:10 pm
by Mark O'Neal
That defies logic....and physics.