Just wondering what you guys used Piston ring gap formulas Bottom ring gap should be 20-30% larger than top ring gap. Top rings NA gap = .004" per inch of bore diameter Oval track = .0045" per inch of bore diameter N20 = .005" per inch of bore diameter Turbo/super = .006" per inch of bore diameter. for street, lower hp I would go .005per inch bore, full out race .0055 per bore and what ever you make the top at least the same on the second ring if not .001-.002 bigger, never had any problems that way. theirs a saying if you build to tight everybody will know,(BOOM) you build loose your the only one that knows. I think i'm going to use .0055 forumla 3.830 x .0055 = .0021 ring gap 1st and do .0023 for 2nd What about the oil catcher rings? .0015? .0019? .0025?
I always look up the manufacture spec if I can, though they generally all seem to be in the same ball park. Those numbers look like they'd keep you out of trouble. Likewise on the second ring being a hair wider. I've never gapped the supporting rings of the oil ring, which of course is overlapped.
Yeah I simply didn't know specs for supporting rings Imagine there would be a spec sheet in the piston ring box
No I don't think there is one. they just have like a 1/4" gap (iirc...) as they are not there to push against the cylinder wall they have a fairly irrelevant gap.
yeah i know about them I wouldn't want to run a gapless 2nd ring though...sounds like it'd compound the problem of flutter, which is why you're suppose to have a larger gapped 2nd ring versus first
The manufacturer's guidelines are a starting point. If you call them with specifics, they'll suggest something. You'll notice those guidelines vary somewhat with piston material. If you are running 9000rpm NA, you would want more...Boosted, are you talking about 7 psi or 25? Again, more... Bill Trovato says he runs .060" gaps in a Nox Olds with no ill effects. That Total seal top rings seems more attractive now, doesn't it?