Burken01

iTrader: (88)

So I bought a front mount 76mm turbo kit for my ls6, and was just wondering and can't get a definitive answer on my piston rings...

My forged 347 was built with nitrous in mind, total seal steel top ring set.. top ring gapped .029, second ring gapped .030

it seems these gaps should work fine for a boosted application? thought i would ask for clariffication?

Any and all advice is welcomed..

mightyquickz28

iTrader: (8)

When I was going thru my build, spec'ing parts from the bare block up, I asked my piston supplier (Diamonds from Erik at Victory racing) about ring gap since these were custom purpose built turbo pistons. He said almost verbatim what you have here. He said "Top ring = .028 - .030, 2nd ring .018 - .020"

However, my machinist, who builts a lot of forced inductions for various engines, felt it should be "top ring = .022, 2nd ring = .019" so I went with that. Perhaps Jim thought it could be tighter on top because I'm a mostly street, little strip application. I run 93 octane pump gas all the time, no meth/alky/water injection, run a mail order tune (PCM4Less), no smoke on acceleration/deceleration, no detonation, have approx 8.8 CR and have run up to 18psi on my T76mm.

So it sounds like, based on Eriks recommendation you'll be fine, especially at the track. Maybe a little more blowby at low RPM's/light loading.

stevieturbo

You'll be fine with those. The only bad thing you can have with ring gaps is too tight.

Loose gaps will have minimal effect, and blowby will be down to bad ring sealing, not the gap unless it was absolutely huge.

9sectruck

iTrader: (9)

005-0055 per bore size and I always open up the seconed ring bigger, if the compression gets by the first ring let it go down to the crank case no need to trap it between the top and seconed ring, may cause the ring land to pop on the top ring,
my .02