95LT1Z28

My LT1 had severe blow-by towards the end of last year. Around 6,200 rpm's oil would be pushed out the oil dipstick tube all over the engineand I also had white smoke pumping out the oil filler cap. I pulled the engine out and everything looked pretty good no scratches in cylinder walls. As I was pulling out the pistons 7 out of 8 had the top piston ring broken in half! The ringlands on the pistons are fine, just have the broken top rings. What would cause the top rings to break into 2 pieces on a cam only LT1 engine? I have about 10,000 miles on this setup and the engine was still running great besides the white smoke from the oil fill cap. I have a XE 224/230 with supporting mods and a PCMforless mail order tune. I am going to rebuild the engine, but would like to know what caused this to happen so it doesn't happen again!

Jeff

wrd1972

Are you sprying?
May have been detonation.

95LT1Z28

Nope, no spray or boost ever - just a cammed, naturally aspirated LT1.

93Z28Sam

Incorrect ring gaps could have caused your problem. Maybe they were too tight. What did they set the gaps at?

96capricemgr

Good chance it was too lean with too much timing.

95LT1Z28

The motor was bone stock from GM when I did the cam upgrade, engine only has 86,000 miles. I could see too much timing or running too lean, maybe I will get with Bryan at PCMforless so he can recheck the fuel and timing just to be on the safe side.

GMRL

Did it ever overheat or run low on coolant? Besides detonation, thats one of the leading causes of ring failure.

87bandit

get that thing on a dyno when you fix it, no reason to reuse the possible source of your problem imo