bad cutt

iTrader: (5)

I am building a 5.7 aluminum engine. diamond 3.905 pistons, wiseco 39050gk rings i am getting conflicting info as to what i should file the rings to. I was thinking .022 and .024. diamond says .o27 and .029 that seems a little large to me. what do you think, oh and i am running a t4/ t66

DeltaT

iTrader: (5)

The specs diamond told you match what I got for my pistons and hellfire rings, for the same boost range. If you make the gap too small, and the ring ends butt, you will lose a ringland at best. Bad stuff.

Jim

xfactor_pitbulls

iTrader: (16)

.020-.021 and .024 are good numbers. .027 and .029 are too big. .020 is enough tolerance that you will be fine. We set my last shortblock up at .019 and .023

koolrayz

iTrader: (26)

the ring manufacturer should provide the best guidelines. Different rings are made from different materials that have a different rate of thermal expansion. I gapped my wiseco rings at .024 top, .026 bottom

NAVY

20-22 it is good for 12 to 15 psi

chriswtx

iTrader: (5)

I run .028 and .030 on my Diamond 3.905 pistons.. No problems here..No oil use or anything...I boost up to 18-20psi...

bad cutt

iTrader: (5)

i run .028 and .030 on my Diamond 3.905 pistons.. No problems here..No oil use or anything...I boost up to 18-20psi...

i have had a problem blowing head gsakets on boost over 18 i am running arp studs and blew felpro and cometic gaskets on 20 psi, i have yet to have a problem since going back to the gm gaskets and they ar about 1/4 the cost. I have also stepped it down to 14 psi and turned the power back down to quit breaking the trans.