Hey everyone,

I have an 08 H/C/I Z06 that started making a pretty terrible noise recently. The car has 11k miles, I guess you can say it's been run hard, heads have been checked, exhaust valves and all valve guides replaced. I don't believe it's part of the rocker/needle bearing problem lot. The noise becomes apparent when it's warmed up.

Here's a video: https://youtu.be/nM8bZQhYcVo
At this stage all I'm trying to do is form a plan to diagnose this thing, I have plenty of time and not a lot of money (as usual). My goal would be to not run it anymore but to still find a definitive cause. That way I can tow it to a shop or start pulling the heads/engine myself, but I'd love to have an idea what I'm dealing with. Last thing I want is to be knee deep in parts and no idea what the issue is. So far all I've done is make this video, panic briefly, then do an inconclusive compression drop test by pulling injector connectors.

Any ideas to single out a problem source without running it would be very appreciated.

 

Could very well be a broken valve spring. Do you have a CEL?

Perhaps start with removing the plugs, and then the valve covers to see if there is any obvious damage. Maybe you could rent a bore scope to look into the cylinders. Then move on to a compression test from there.

 

Thanks for the reply, I'll start with the plugs and valve covers when I get home.

Unfortunately no check engine lights so no help there and it doesn't sound like it's missing. I added another video to YouTube (recorded at the same time as the last). I think the sound is a lot louder in this one.

 

Kind of sounds like a bearing going out.