Guy down the street from me comes in my driveway with his WS6..LS1, stock with Headers, making one hell of a wierd noise.

On warm startup it knocks for about 15 sec, then goes away..I thought it was a Rod Bearing till the sound went away. No metal in the oil, good Oil Pressure, he said it runs great. Sounds doesnt come back till you shut the car down and re-start it.

Sound is on the passengers side, up top kinda.

The only thing I can think of is a Lifter bleeding down when he shuts the car down, and when it starts it gets oil pressure eventually.

Thoughts?

 

Maybe lifters, or piston slap.....does it do it on cold start, or on warm start too?

 

Warm and cold..I already ruled out the piston slap..he was driving it and came up to my place as it was normal operating temp.

 

Sounds like it may be time for a new set of lifters for him.