Well, I dropped the oil pan today to replace the o-ring on the oil pick up. I went ahead and replaced it, but the old one was perfect. No splits or tears in it.
I guess i'm just the proud owner of one of the worlds loudest piston slapping engines.

 

I had a noise like that about 8 months ago. Power was normal but it just would be loud as hell when cold. Chased my tail looking for it for a little over a month. Changed the oil pump o-ring, timing chain and still had it. Did a compression and leakdown test and both came back good. Not giving up, I ended up pulling my heads and found a piece of the #4 piston gone. The top of the piston popped at the gap of the first compression ring.

My whipple came off and will not go back on until it's intercooled. I also swapped an LS1 instead of repairing the 5.3.

 

[QUOTE=hohl]I had a noise like that about 8 months ago. Power was normal but it just would be loud as hell when cold. Chased my tail looking for it for a little over a month. Changed the oil pump o-ring, timing chain and still had it. Did a compression and leakdown test and both came back good. Not giving up, I ended up pulling my heads and found a piece of the #4 piston gone.]

I musta missed the fact that you were having trouble, Ranwalk. I had a couple pistons break from detonation in the first 6 liter but I drove it like 200 miles before I realized there was a prob. It was quiet as a mouse even with broken pistons. If you have a serious noise, I would bet you have an internal prob.

 

If it is somthing broken, how can the noise go away after the engine gets hot? There was no metal in the oil pan, everything looked great

 

thats a good question, but randy, i started paying attention to my engine after your post. mine does it real bad in the a.m. too. then when it gets warm, it goes away. i for one am not worried about anything. it was loud and sounded like a rocker arm off but it went away. so maybe, we are having the same issue here.

P.S. it has been cold here, our trucks are used to the hot near 100 degree days...

 

Does it have low oil pressure? Change the pump out to a LS6 pump...you can also shim the pressure relief spring a couple thou and bring the pressure up a bit.

If its just noisey when its cold....seems to be a LS1 trait...especially modd'd ones. Does it sound like a sowing machine?

 

mine was noisy when i first got it. talked to a few mechs and asked on other sites, seems pretty common. switched from mobil 1 5-30 to 0-30 even though it never really gets cold here. quieted it down a bit on start up. still a little noisy though. the piston heating up and sealing thing never made much sense to me, seems if there is enough slop to make noise it should blow smoke and mine never has.

 

Gotta be the 6.0. Mine has done it from day1. I replaced the oring also and the old one looked fine like yours. Just by looking at the oil press gauge mine has less pressure than my wifes Tahoe at all rpm's. Not much, but it is less. I might try the LS6 pump sometime but with the way I drive, if it was gonna bust, it would have long ago......

Mike

 

You guys are making me feel better. It never did it before, so that's why it has me so concerned. It has allways had the normal cold engine piston slap at idle til the engine warmed up. This noise it makes now when accellarating may just be the same thing only louder. My oil pressure is great. I know it's hard to tell exactly on theses guages, but it's over 60 when cruising at hwy speeds and after then engine is good and hot it will stay a 1 - 2 bars over 40 at idle.
So, maybe it is actually ok. Dont loose engines make more hp anyway?
One way to fix it, I guess I could allways get louder exhaust and drown out the noise

 

Out of curiosity I pulled and checked the spark plugs. They all looked good. One of them had a few reddish spots on it,from additives in the fuel I assume, but other than that they were perfect.No signs of detonation, no oil.