VetteVinnie

UPDATE 5/23/2013

The sound turned out to be a bad lifter that came apart and was grinding against the cam lobe. If you read through the thread, you will see a picture of the damage done to the camshaft. This is for anyone else who happens to encounter the noise(s) that it was creating (rhythmic squeaking and eventually a grinding sound).

Aside from a replacement Phantom cam (with many thanks to Shawn David at Lethal Racing for a quick turnaround and excellent customer service and to Terry Wallace at Vetttech for putting up with me and my frequent questions ), car is now getting upgraded with Morel hydraulic roller lifters, the larger capacity OEM dry sump tank, and the Aviaid tank insert and windage tray, holding true to my philosophy, "If it breaks, upgrade!"

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Intermittent, rhythmic squeaking that changes frequency with RPMs. My guess is the belt, but hoping it isn't an exhaust leak. Sound familiar to anyone?

Car still runs like a raped ape.

Any thoughts are greatly appreciated before I tear into it.

Turbosixx

Bearing on the tensioner? Spray a little WD40 on it to see if it quiets down.

Dirty Howie

I have something similar. Close your hood and see if its easier to hear through the front grill.


DH

VetteVinnie

Oh, I can definitely hear it with the hood closed. Drives me nuts because I lost my Mild 2 Wild remotes and can't open the exhaust with the windows down to drown it out. I actually hit the belt with some conditioning spray and it seemed to help a bit. I will probably pull the belt, check the pullies, replace the belt (after all, it's over 5 years old with 29K miles on it) and then see where that gets me. All of the header bolts are still tight and I see no carbon residue anywhere around them.

Side note, anyone wondering whether their loud sewing machine sound when running headers, dual springs, and higher compression is normal can wonder no more. It has always sounded like that. Clackity, clackity, clackity... It's the squeak, squeaking that needs to die a horrible death.

jedblanks

It could be the bearing on the tensioner or idler pulley. Pull the belt off and see if it stops.

It can also be the tensioner leaning towards the front of the car from wear and allowing the belt to run ****-eyed across the pulley. That's the normal mode of failure for the tensioner part. It's not enough to see it.

VetteVinnie

Well, the verdict is in. I spent the weekend tearing into it only to find that it was not related to any of the accessories, pulleys or belts. After replacing a suspect idler pully and the main serpentine belt, the sound was still there. So I removed both belts and fired it up - still had the sound. Conclusion: Internal.

Pulled the valve covers, nothing. Pulled the intake and the valley cover - visible scoring on the camshaft. Verdict: Broken lifter(s) grinding against the cam lobes.

Gotta love it. And to think I just posted "no engine problems" in another thread. Lol! Damn it.

Note to others, when changing out your cam, make sure you change out the lifters also. Apparently those aren't all trouble-free, either. Glad I shut it down and inspected it and didn't keep driving. Who knows what could have happened.

z0sicktanner

Man that sucks. seems to be another common issue good luck on the fix

VetteVinnie

Thanks. It's undergoing surgery at Vetttech.

Replacement Phantom cam is inbound. Gotta love Shawn's exceptional customer service over there at Lethal Racing.

And, yeah, I've seen more than one thread involving stock GM lifters coming apart. Is that the next "sky is falling" thread?

erichg1000

I had scoring on my stock lifters and stock cam when I removed them, but they didn't come apart, they were still all in their correct format but the wheels and cam had some light scoring on them. You don't have any pics??

VetteVinnie

I have a preliminary pic, but I can't access Photobucket at work. I'll put it up tonight. I'm sure I'll have more when the heads come off the car. The wheels actually came off. That's the grinding, squeaking I was hearing - the empty wheel socket in direct contact with the cam lobe.

Just ordered some Morel 5206 LS Pro Series Hydraulic Lifters. One less problem to worry about.

Dirty Howie

Tough luck and bad Karma .....

I replaced my lifters that looked good with 37K when the heads were redone.

Good luck.


DH

erikszr1

bad lifter....ooops I didn't see the rest of the posts.. good luck with the repair. its fairly common. maybe not so much in corvettes but ive done quite a few on ls motors in general.

mariofromnewyork

Glad you caught it in time!

Lesson to me read entire thread before posting!

VetteVinnie

Here's a picture of the damaged lobe:

VetteVinnie

Original post updated for archival purposes in case anyone else encounters this noise.

Landru

Glad you got this resolved.

You must be in oil.

VetteVinnie

Thanks. Me, too.

Negative. I wish. Otherwise I'd just forge the entire bottom end assembly while the car is apart and be done with it. I don't drive it like I stole it anymore, so I'm not as worried about the pistons giving out. At least it got a good shakedown where I was able to identify and replace the weak components. If I ever decided to sell it, the new owner could have solid peace of mind that it will be reliable going forward (knock on wood - haven't replaced the transmission yet, but the stock TR6060 should be plenty strong). And it has never seen drag radials and probably never will. R compound road race tires? Maybe in the future. We'll see.

Dirty Howie

Evil

Can you post a new video of your motors sound now. I am not sure which sound in your original video relates to the cam grinding. I have a rythmic sound too, but not sure what is ??


DH

ConfusedGarage

Are you running running solid stem exhaust valves? The main reason I didn't switch to SS valves when I had wcch completely redo my heads was concern of the extra strain on the lifters. Could have been a random failure either way. Sorry to hear, best of luck on the fix.

briancb1

How many miles were on the lifters?

How many miles were on the performance springs you had?



My rule of thumb, personally, is change the springs at 10K and the lifters before 20K once you have a performance cam setup installed. A weak spring can allow a lifter to start bouncing. All valvetrain components are now considered consumables IMO.


But good catch, glad it didn't take out the beast. We should meet up sometime, you go to any events around here?