ss2z06

After racing last weekend at thunder hill I now have a chirping sound that is most noticeable at idle. It has the same sound when you have an idler bearing going but sounds more in the center of the motor. It’s definitely not in the front and can’t tell a particular side. I’m suspecting something in the valve train. Other than dissembling the heads any ideas to help isolate? On a separate and slightly related note are arp head bolts reusable? Car and mods are in my sig
​​​​​​​ Thank you

Apocolipse

Take belt off. If still chirps - have ur answer.

MTPZ06

Bad lifter will sound like a bird chirping. Go to Harbor freight and grab a mechanic's stethoscope for like $5 (or Amazon if no Harbor fright near you) to help isolate where teh noise is located.

ss2z06

Both are correct and I realize that. You both gave me an idea because I was going to remove the belt but also wanted to make sure it wasn’t the blower. Now thinking about it that has its own belt too. I’ll remove one, recheck, and then remove the other. Thank you

ss2z06

So I confirmed it was a lifter. I pulled the heads today and found one that has a flat spot and a couple with what looks like pitting on the edges. The cam has about 23k on it. The lifters are stock. I'm now replacing them all of course. Any ideas on what causes that? I can supply a pic if that helps. It's hard to show the flat spot on the roller but the pitting can be seen.

Apocolipse

Usually valvetrain instability.

ss2z06

Just so I make sure I don't have this happen again do you mean valve springs? or lifter pre load? I will be replacing the valve springs again now anyways because they have 23k on them.

Apocolipse

Usually its from a weak valve spring allowing the lifter to come off of the cam profile and smashing back down.

ss2z06

Ok, thank you. Then it sounds like i'm on the right path then with the repairs.