i have a 2000 z28 with 132K on it and i just bought it a couple months ago with about 127K on it...it recently has been having some engine noise...on a cold start the initail first 20-30 seconds its quiet.. then after that it idles down just a tid bit and it starts to have a slight knock..i think it is a rod bearing..my buddy thinks its a wrist pin..the knock goes away when the engine is warm

 

Mate, id be getting that thing on a hoist asap and having a good listen. It may be piston slap

 

If it goes away after the engine is warm, then it is probably just piston slap.

 

so i should probably be tearing it down this winter???

 

No need to tear it down. Piston slap is completely normal in these LS motors.

 

it sure scares the hell out of me tho..not something i want to be hearing

 

is it a sloppy sort of sound or a hard knocking sound

 

That's an F-body for you.

 

kinda sloppy...kinda like a rod but doesnt make sense to be a rod after it warms up..cause after its warm its all fine and dandy..runs like a raped ape

 

Its completely normal...ITS YOUR PISTONS! fergit about it.

 

and have been told that it's my lifters and should not be worried about it. i have to ignore that talk tho cuz it's not their car to deal with. i hate the sound of it!!!! unlike the thread starter my sound starts from the turn of the key and goes in and out. it does stop most of the time but if i rev the engine i hear the sound again and as the revs drop it fades out