well i finished getting the block apart last night, and i found two spun rod bearings, one of which was hardly anything left, and a broken piston ring. i'm sure there could be alot of reasons, but anyone know what could have broken a piston ring? i know when i took it to the track the night that it started knocking...i did hit the rev limiter in third...but don't know if that would do it. the spun bearing was on the las piston on the passenger side, and the broken ring was on the first piston on the passenger side as well.

it wore a pretty good grove on the crankshaft where that bearing was spinning.

 

How many miles were on it, and how high were you spinning it?

 

First quess would be detonation.

 

more importantly which ring broke? I assume the compression ring (top ring). If its not a defective ring massive blowby causes a ring to break. Did you run nitrous in that motor?

 

yeah, the person who had the car before me ran nitrous don't know how much of it though...yes it was the top ring that was broke..and someone metioned blowby..well when i took the valve covers off i smelled gas pretty good..but the whole thing is getting rebuilt as i speak so hopefully i'll have better luck when its done.

 

Isn't it funny that just this months Chevy Hi-Performance(December 2006) magazine has information in it about LT1's from Golen Engine Service.
And I quote
"In their day, LT1's were known to occasionally spin a rod bearing. According to Golen, the combo of 0.0015 to 0.0018 inch factory bearing clearance and 5W-30 OEM-specified oil wasn't up to forced-induction apps or other hard useage. GES opens up the clearance to 0.0025-0.0030 and specifies 20W-50 Valvoline oil."

So now we know why! Forged internals and 4 bolt mains aside.