I can not for the life of me fix this noise:


The noise started after I did heads and cam swap with all the supporting parts (lifter, pushrods, timing, etc). I've driven it a hard 1k miles with this noise. I would think it would have blown something or gotten worse if it were catastrophic. It gets really bad between 1500-2000rpm then pretty much goes away. It does seem to be load dependent or whether going up or coming down in rpm. It only happens when hot, it's perfectly silent when it's first started up.

I've checked lifter pre-loads numerous times, even swapped them to a different length and got the same noise.

I used brand new GM/Delphi LS7 lifters from TSP. I'm getting 55-60psi oil pressure at cruise.

When looking into the engine bay, it sounds like it's coming from the rear but not low enough to be a rod.

I've pulled the valley cover and the cam lobes don't look awful to me, but may be worse than they should be for only 1000miles.

Is there a sure-fire way to know it's a lifter before tearing apart the heads? Or would a cam bearing cause this noise?

 

Did you measure for correct pushrod length?

 

.....

 

stock rocker/rocker arms? what type of lifters, LS1 or LS6?

 

LS7 lifters. Stock rocker arms.

 

Cam bearing will do that. id def pull cam OR put a magnetic drain plug in the pan and check it to see what is going on. but still pull cam and check. better safe than sorry.

 

Have you double checked your header bolts after a few heat cycles. Exhaust leak at the head will sound like lifters. Re torque header bolts at the head just to be sure it isn't something simple

 

I don't hear a "metal on metal" sound at all, sounds like exhaust to me as well. I also only heard it when you moved the camera to the center of the car.

 

I'll have to dig out the torque wrench this weekend and check them. It doesn't sound like the usual exhaust leaks I've heard to me.

 

Sometimes its hard to get a good recording of things like this that can be posted.

 

It does sound like my lifter did alittle, when one went bad. But it's impossible to tell from that vid like stated. Start simple. Re-tourqe header bolts. So on so forth

 

Retorqued header bolts to 18ft-lbs. Still there. Double checked pushrod length with the "turn method". On average between 0 lash and torque is about 1-1/3 to 1-1/2 turns, which should be .0625-.0705" preload. A little on the low end, but should be in spec.

 

Have you checked for aerated oil? This will cause loud lifters.

 

Does your oil drain plug have a magnet? It might be time to do an oil change and run vr1 20w50 and put in a new magnetic plug. Like mentioned inspect the dip stick while the engine is running for tiny air bubbles in the oil on the dipstic

I also suggest using a mechanics stethoscope to listen to the head on each cylinder to pin point the noise location. You can also get under the car with it running and use the noise test to try to find if it's prominent on the top or bottom

To try to narrow it down further you could also perform a compression test and leak down test before you try to tear down the motor.

 

I get 0.077" for the 1-1/3 turns. Did you check the exhaust connections in addition to the header attachment to the head?

 

Wonder if there was ever a resolution to this?

 

After talking to a lot of people, it got chalked up to the FAST intake acting as a resonator.

Car ran great and never had issues.