MadLion007

hey everyone... new to the forums....have an 08Z with the lingenfelter head and cam package. 18k miles... recently decided to be a show off at a car show and do a burnout..bounce of rev limiter at 7k but not for long. soon after i heard what sounded like a squealing belt. the sound subsided, went away and never came back ..a few weeks later (i had driven the car in between this time but at normal speed) i was getting on the car a little and i noticed the noise came back again for about 20 seconds and threw the blinking check engine light indicating a timing cut, but this lasted no more the 20-30 seconds. i thought at the the time it was the tensioner for the AC but after jacking the car up and listening the top of the motor and the bottom end it seems like the noise is coming from the oil pan and i can also hear it from the top of the cylinder head as well. it sounds exactly similar to the noise in this video but not NEARLY this loud: (this is not my car)

reason i am posting this is because i am NOT experiencing the common spun bearing issues: oil pressure is perfect and i did do an oil change and found NO metal shavings and, from what i understand it could also be a spun rocker roller bearing as well... any thoughts?

extrapilot

Take the old oil filter and cut it open, look for metal in the pleats of the filter element.
Hard to make out the "spun rod bearing", as it's usually more of a knocking noise than this squeaking noise that's so blaring in the audio. But, if your is more of a squeaking noise, I would suspect a lifter issue. Big cams and heavy valve springs can ruin the lobs of the cam and the rollers of the lifters.
Have a tech pull the valve covers off, start car, if noise increases, it will be more obvious that the lifters are the issue. While off check the rockers, but don't think that they would make this kind of noise.
Can't rule out the belt tensioners, check them also.

rjacobs

thats lifters FOR SURE.

Dont run that motor IMO.

The squeeking you hear is possibly the lifter going through the bore at an angle. You will **** up the lifter bores and then the motor has to come out to bush the bores, at a minimum. It also could be the wheel on the lifter.

But that tapping is a collapsed lifter, which sounds like it has caused more damage.

MyLS1Hauls

Yeah, that's the lifters. The squealing is actually the roller skidding on the cam lobes. I'm guessing you have either a GT19 or GT21 cam in there? The motor really should come out, and be flushed at a minimum...entire oil system too. There are going to be metal shavings everywhere in the engine. I was where you are last year at this time. My lifter bores were perfect, but I found 3 lifters with bad bearings. New motor has much milder cam lobes.

Luckily the only damage my motor had was the cam/lifters and the oil pump. Everything else was ok. Ended up rebuilding it while everything was apart though. Good luck.

MDSilverVette

I agree. I bet 1 or more of the lifters are pitted. Are you getting any misfire codes?

C6smackdown

Sounds like a lifter turned in the bore. That is definitely No Bueno!

MadLion007

Since the last time I started it about over a week ago it had gotten slightly louder I have not started it since. I have gotten no misfire codes and my oil pressure is at normal Psi. Going to have it towed to the shop next week and have them take a look.. It's deff. a collapsed or about to collapse lifter just hoping it's not bad to the point that it damaged the cam!

Spoolin8

I think like 9/10 times when lifters go they take the cam with them. I had lifters go on mine last month (SC LS2 aftermarket cam, stiffer dual springs, pushrods, etc). I caught the noise immediately and pulled the heads. I found 6 collapsed lifters, with 4 being really bad, but fortunately none of them got sideways in the bore and the rollers only had very minor wear along with the cam. Kept the cam and swapped in brand new lS7 lifters. Good to go but I got lucky.