Hey all, I was wondering if you guys could help me diagnose this strange sound coming from my '01 LS1. The car is not a corvette, its actually an 01 Camaro Z28 (M6), but I figured since a lot of you are LS1 pro's, you could help me diagnose it. The engine has the typical bolt-ons and an F13 cam, 99k miles on the odometer. There is a really loud ticking coming from the engine that developed a few days ago on my way to work (see video at the end of this post). I've done several searches on here (as well as other LS1-related sites) and youtube comparing this noise to common noises (belt tensioner, lifters, pushrods), but none of them sound the same as this one to me. The noise is there all the time (idle, acceleration, deceleration), and varies according to the rpms. Any guesses where I can start to look?

I changed the oil today, it did not smell burnt and there were no metal shavings in the oil/plug, oil pressure is good. I haven't ruled out belt/pulley issues, but I wasn't sure how to test for that (I can't start the engine with no belt, can I?). My next idea is to pull the valve covers and check the valvetrain, see if anything looks out of the ordinary.

I can't really afford to take it to a mechanic right now, so any help is greatly appreciated!

http://www.youtube.com/watch?v=eHsz7qStdlA


2/29 UPDATE: Ran the engine with no belt, the sound was still there. Pulled the valve covers and checked the valvesprings/rockers/pushrods. I couldn't find anything damaged, all seems to be in good shape. I guess the next thing to check would be the lifters.

 

See if you can isoloate the noise to a bank. If so, pull the appropriate valve cover, and inspect the rockers/springs....and yes....you can start the engine without a belt. Don't let it run very long, because you are running off the battery.....and the water pump is not turning.

 

my guess is broken valve spring. If not then i would say you ate a lobe on that futral cam. Seems kinda common from what I hear.

 

Seemed to get louder when you moved to the driver side. If I had to guess, it's either a broken valve spring, bent pushrod or a rocker lost it's bearings. Where do you live? Maybe someone could go listen to it in person.

 

I forgot to mention in the original post that the car is an M6. Thanks for the suggestions! I have to work all day today, but I have the day off tomorrow so I'm planning on pulling the valve covers off and checking valvesprings, rockers, and pushrods. I'll keep you guys updated...

 

Well, I popped off the valve covers this morning. I went through and checked the valvesprings, rockers, and pushrods. Everything looked good, I couldn't see anything cracked/bent/broken. I didn't pull the heads off the car, so the back springs on the passenger side were very difficult to inspect with the limited amount of space, but from what I could tell nothing was wrong. I guess the next thing to check would be the lifters. I'm going to have to wait until the weekend to dive into that project, since I've never pulled the heads off before and I want to do it with plenty of time.

Any chance that it could be anything else other than a bad lifter? I'd hate to go through all that work and put it back together only to start it back up and hear that damn noise again!

 

Why did you pull both sides? Could you not isolate the noise to a bank? Are you using a stethoscope? Did you run the car without a belt?

 

I used a large screwdriver in lieu of a stethoscope, and heard the noise slightly louder on the driver's side (on the top of the head, near the intake manifold). After pulling the valvecover and not finding anything, I figured it would be worth a shot to check the passenger side valvetrain as well.

And I forgot to mention, I did run it without a belt, there was no change in the sound.

 

Did you remove the pushrods? Inspect the rockers for needle bearing loss?

 

Yep, all looked good. I was kinda hoping I would find the answer there, but no luck.

 

well since all that was fine I will say that you ate the cam.

 

Any chance it could just be a bad lifter? I'm planning on pulling the heads next, I may pull the cam out at the same time to check it. Unfortunately I don't have a lot of time on my hands so it'll have to wait until the weekend (or maybe find a decent local shop around here who can do it for not too much $$$).

 

possibly but to me it sounds worse. You will know when you get the heads off. Just pull the lifters and check the rollers. If one is damaged then it's the cam. You will be able to look down at the lobes after the lifters are out. I know futral had some bad problems with some of their cams.

 

I had a stuck lifter on my '00 SS Camaro M6 from over-reving. I isolated the lifter and injected ATF in that push rod. Let it set overnight and started the next morning. All was well and never had a problem since.