Bad oil rings

[shmit001]

Hey, I've got bad oils rings in my redtop sr20. Its still got good compression on all cylinders, new valve seals, the crankcase is properly ventilated, but it smokes big time on acceleration. I've been planning on replacing the pistons with .2mm oversize, but the budget is getting tight, so my question is this: If the bore isn't scored up, could I get away with just getting a new set of rings and a good re-hone? Has anyone else had this experience?
thanks

[GSXRJJordan]

If it were your oil-control rings, you'd see oil/smoke on decel, not accel. If it compression tests 'normal', it's your turbo that's blown.

The good news? Turbos are cheaper than rebuilds.

[shmit001]

i'm pretty sure its not the turbo. I've inspected it. There wasn't any oil leaking out of it on either the exhaust side nor the intake. I've also inspected the chamber with a boroscope and it was soaked in oil. I'm thinking the oil rings lost their elasticity when I overheated the motor slightly, so they don't scrape oil off the piston wall on their way down. And my boss drove behind me, we're pretty sure its rings. I jsut wanna know if I can just replace them or if I need to get new pistons too. I know with new rings theres a chance that they won't seal properly without a re-bore and oversize pistons. But it wasn't the compression rings that went, just the oil rings.

[shmit001]

I should add that the cylinder walls are mint. There is no ring ridge, and theres even still a cross hatch pattern.

[GSXRJJordan]

I should add that the cylinder walls are mint. There is no ring ridge, and theres even still a cross hatch pattern.

Interesting. If there's still a cross-hatch pattern, the engine's not even broken in lol.

To answer your question, it's undoubtedly yes - you can re-ring with the existing pistons if all the ring lands are still intact... sometimes everything looks good, but once you pull the piston out, the ring land disintegrates in your hands lol.

So yeah, pull it apart, take a look at everything, scuff the cylinder walls if they need it, re-ring, throw it all back together, and be more careful during break in this time.

[dubtastic]

you try wet compression test?

[shmit001]

Yup, wet tested it. Didn't do much. I talked to my old boss about it. I'm gunna measure the clearances between the pistons and the cylinders, he says if its .002-.003ish, then I'm good to go, as long as the cylinder is still round. Don't have the tools for THAT so its too the machine shop for out of round-ness and a good hot bath. :)