SacCityCorvette

Hi,
I have a 02 Z06 with a 440 ci ls2 with ls7 heads, manifold, big cam ect.
Its n/a and makes 570wrhp. Anyway recently especially when cold I hear this chirping squeaking off and on that comes from the passager rear in the valve cover. I pulled the cover and did a visual inspection of the rockers and springs. BTW, It has Yella Terra roller rockers. Everything looked and felt normal. Is it possible for the roller on the lifter to skid on the cam and make the noise? It dosent do it as much when it warmed up.
Any idea what could cause this sound?

Thank you in advance!

Badd LS6

Could be a spun bearing or the beginning of a lifter going out, I wouldn't run the car anymore and get it checked out ASAP.

RonSSNova

You could remove the suspected rocker pair and pushrods and start it and see if the noise goes away. You wouldn't need to run it very long. A lot of work for sure.
I would also drain the oil into a light colored clean container and look fo metal. Cut the filter apart as well.
If a lifter is failing, the cam will die rather quickly leaving metal in the oil.

Ron

Joe_G

I had that problem and it was my belt tensioner. Chirping when cold, quiet when warmed up.

They are pretty cheap and easy to replace.

glenB

Yes, a bad lifter does make that noise, but so does a rocker trunnion.

pewter99

cam bearing perhaps

SacCityCorvette

I have a Ktech solid tensioner on it. So I'm pretty
sure its not that.

SacCityCorvette

I hope its a rocker trunnion. How do you test it? The engine has 16k miles and the Yella Terra rocker have about 6k miles on them.

DSOMC6

You could swap the rocker with one on the other side and see if the noise moves with it.

If need be you can also pull the intake/valley cover off and get a partial view of the lifters/cam lobes.

glenB

What he said

SacCityCorvette

Good idea! Ill let you know what I find.

seans857

Yes it does... I had chirping noise... Change belts,tensioners and the UD pulley but the noise didnt go away... Later found out that I could have run without belts to diagnose any belt and pulley issues when engine is cold....

Remove your heads and check it before its too late.... My lifter broke and two big chunks had already dropped through the cam.

SacCityCorvette

Update- Pulled valve covers, intake and valley cover. Could only see the rear 3 lobes and front 3 lobes. They all look good. The noise comes from the rear. So I moved the rear rockers to the front and the front to the rear. No change. Pulled belts no change. Drove it all over the place last weekend and its seems fine. Only on cold start it makes the noise and goes away as it warms up. It doesn't sound like its getting worse. I will keep looking.

Badd LS6

Could be a spun bearing ..does the squeak sound like its deep down..are you paying attention to your oil pressure??? You wont always lose pressure when you spin a bearing but its a sign that you could of.

I would still pull those heads and thoroughly inspect the lifters.my motor is currently out of my car because I trashed lifters..doesn't take long for them to get so bad they self destruct,especially when their spinning in the bore..lol

AndyMac

Does it sound like this?

https://www.youtube.com/watch?v=uPGRAsxrRwU

If yes, you have a pitted cam lobe and/or lifter roller.

JUIC3D