I R Gunnr

Freshly rebuilt iron block, went all out with forged internals, aligned honed, and short blocked by a very reputable shop in Memphis TN. Has a mild cam with double valve springs and properly sized comp pushrods. The noise is actually more present in the video than standing next to truck. Can barely hear it from the engine compartment, gets louder in the wheel well, and is loudest underneath. Using a mechanics stephoscope I found it was loudest on the number 7 header tube right at the heads. However, the same noise is present on the passenger side, hard to tell if it is coming from that side or just echoing over. I know the LS is a loud engine and the long tubes don't make it any better, but this seems like more than just normal noise.

Good oil pressure
Broke in with break in oil, currently running royal purple 10w30
No over heats

Thoughts? Additional troubleshooting steps?
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NHRAFORMULA00

iTrader: (2)

sound like lifters. it is always possible that the oil pump o ring is pinched, it adds air to the oil pressure and will sound like lifter chatter at idle.

RockinWs6

Check the engine oil for tiny bubbles. Also headers makes the valves sound much louder than they sound with stock cast iron manifolds.

I R Gunnr

Found tiny bubbles in the oil. Stopped driving it and going to pull the motor when I get time. I was ridiculously careful with the o ring. It's either the wrong o ring, which I don't since I researched it to death, or my pickup tube is out of round or cracked.

How bad do you think the bearing damage will be? Have about 2.5K miles like this. Oil pressure gauge always showed good pressure, lowest it ever got was 40 psi.

RockinWs6

The bubbles won't cause any damage but the lifters will be loud. Heres what I would do, run the engine up to full temp then check for bubbles. Cold the oil will have some bubbles in it but as it warms up to full temp they should be gone. If its full of tiny bubbles warmed up you need to find why air is entering the oil BEFORE the pump. Could be a tiny crack in the pickup or something with the oring. Also might be a good idea to add a cradle to the pickup tube where it bolts onto the pump. It allows you to use 2 bolts to secure the pickup tube to the pump.

Now I had the same issue but I used TransX automatic transmission sealer to seal the oring to stop the air from getting into the oil stream. But this was on a stock engine that was never apart @ 75k miles.

No reason to pull the engine apart down to the bearing etc because the bubbles won't hurt anything short term. Hell I drove mine like this for 75k before I fixed it.

G Atsma

Oil pump O-ring tech: If the tube has a groove, you need the fat O-ring. If no groove, the skinny one will be it.

BlwnLs1GTO

iTrader: (12)

I don't have the best speakers on my PC. It sounds like an exhaust leak on several primary's from here. But not a reason for bubbles in the oil.
Lifters also have the sound when the PR's are too short. I'd take a look there first since it's so easy to do. check a couple of them and see exactly how much preload you have on them, which lifters (assuming LS7) and make sure they're loaded up enough.

Good luck. Hope it's something simple.