VGLNTE1

iTrader: (1)

So my buddy has a LS6 CTS-V with a cam. all else stock.

The car was hamemred on through 2 gears, and then a loud knock came. He drove the car home easy and said the knocking went away at 1900 RPM but every other rpm band had the knock. OIl pressure was fine.

We checked the valvetrain. all seemed ok. We then pulled both heads and there is nothing wrong with the pistons or any scoring on the cylinder walls.

We then drained the oil. The magnetic drain plug had almost what lookedliek anit-sieze on it. I think it was metal that was so fine you couldnt even feel it. But after it was wiped off, it had a graphite, lead look and feel to it. Is this bearing material?


Also, how do you check if a lifter is bad?

uwood

I was just getting ready to post for the help.

Few more facts.

228/230 116 cam
7.4 Push Rods
Patriot Dual .650 springs

Stock everything else.

Car idled fine, and great oil pressure. It sounded like a shoed horse prancing down the road with a squeal mixed in occasionally.

TooLateVTEC

iTrader: (2)

Well, im gonna say its most likely a rod bearing.

That **** on the drain plug is probably bearing material.

At what RPM did this happen? Was a gear missed and it over reved?

Get ready to pull the motor out.

uwood

It was around 6600 in 2nd and 3rd before I backed out. I never bounced the limiter.

VGLNTE1

iTrader: (1)

this car was also 13.5 AFR. I imagine the detonation took out a bearing. If there is no visible damage or marks on the crank, rod jouornal, are these completely reusable?