That's what the shop says is the problem, It hasn't been fixed yet.

I have air bubbles in the oil until you get it good and hot, then the air bubbles go away and the engine is silent.

 

I believe he has already tried with the belts off and still had the noise.

 

Well the oring hasn't solved the problem............not sure what to do next. One place says its lifter noise, another says its piston noise.

I think its piston noise, If I get it hot enough the noise just about goes away. If I go through a Mcds lets say and get the engine good and hot it quiets down. Once you get out on the road again and start driving the noise starts to come back.

You can actually hear the engine RATTLE when you let off the throttle below 1500 rpms as you drive along. If you drive along steady at lets say 40mph very light throttle it rattles constant until you give it throttle and get above 1800-2000 rpm. Oil pressure is good 42 hot 60 plus wot.

Anyone chime in, this is starting be a major pain in the ***. Link to video of the sound in park.
Here is another thread someone started with the same issue, https://ls1tech.com/forums/new-ls1-o...ston-slap.html


Someone has to know what this problem is.

 

My best guess is when there is no tension on the timing chain the lifters clatter because the cam is not turning steady because of the slack in the chain. I think the cam is actually jittering back and forth slightly from the lifters acting on it with out tension on the chain. This is the clatter I hear as I let off the throttle and the chain goes slack. If I get the engine hot enough I think it grows enough to tighten the chain enough to stop the noise.

Using the CTE of aluminum with a 200 deg F rise (being conservative) shows an expansion of about 0.0027" per inch of the block. I can't remember how far above the crank gear the cam sits but if it's 6" then there's 0.016" of growth total where the cam moves further away from the crank theoretically. This doesn't sound like much but it will take some slack out of the chain.


I will soon find out because I'm having the chain and gears changed shortly.

 

I'm sure I found the answer to this all this noise purely by accident. It got cooler out this week 50-60's and the engine was getting noisier. I was driving and pulling out from a stop light and ran it moderately 1/2 throttle to about 3500 rpms and it rattled like a snake. It had to be preignition and piston noise. So I put about 5 ozs of Lucas upper cylinder fuel treatment in the fuel at 1/4 tank and ran the **** outta it.

ALL THE FARKIN noise is GONE! So it has to be carbon and piston slap. That's the only thing the Lucas could help. I think too my valve seals are leaking a bit and is that carboning up the valves and pistons faster than normal. You watch i'll bet within 100 miles all the noise comes back If I stop using the Lucas.

I do have some lifter noise but that is only at 1st start up cold or hot but it disappears with in about 30 seconds. These engines are really tough to figure out the noises.

 

RockinWS6, what was the final outcome to your problem in this thread. Since some time has gone by is the noise back, gone totally, due you have to use the Lucas all the time? Reason I am asking, I have an 02 Z06 and it is doing the same thing. Interested in hearing the feedback. Please let me know. thanks.

Sam

 

If it was spark knock, more than likely the intake was filled with oil. Low RPMs off the gas and moderate throttle back on will make it ping like a ****. There is a mopar spray you can put into the pcv port into the intake. Forgot the name. Worked like a charm for me.

 

The ENTIRE PITA was caused by 2 things, pickup tube O ring leaking air into the oil and LIFTERS. After running TransX and ATF Dex6 in the engine oil the lifters cleaned up and the engine is nice and quiet. All the noise was from the lifters.

What's crazy is my jeep wrangler is starting to make the SAME NOISES. Going to put some ATF in it soon.

Good luck, it a BS jungle out there in "PISTON SLAP LAND"

Dam I forgot to add I did have some pinging and spark knock that was caused by the intake caked with crap. So actually there was 3 things all at once......what a PAIN IN THE AZZ. Thankfully its quiet now.

Another cool thing is ever since I started putting ATF in the engine oil it stopped using oil.............

 

Drove 300 miles today, quiet as a mouse. I added 2 ozs of ATF just for preventive maintenance before I left. Me Likie Quiet motor.

 

Put better lifters in there. Get some Johnsons. My **** is quiet as hell.

 

Well after reading this and listening to your clips and symptoms , it is one of the few posts I've read that are exactly mirroring mine. I guess I'll return to the ATF seeing as your problem seems so close to mine. It's the constant fast tap at idle from underneath by the oil pan/bell housing that concerns me. But those sound clips of that rattle as it idles down is exactly mine to the tee. Including rpm at which it disappears,cold weather and a heavier oil making it louder.

 

I really don't understand anyone putting ATF in an engine. Its will swell anything that is rubber like seals and O-rings causing premature failure. I would never do that.

 

ATF does not cause rubber/seals/o-rings to swell.

 

It sure does unless its designed for trany fluid as trany parts are. Sorry but Ive known this for 30 years.

 

Transmission seals don't swell and fail using ATF, why would ATF cause engine seals to swell and fail?

ATF does not cause seals to swell but it does condition them so they stay flexible. I ADDED a seal sweller called TRANSX to actually swell the seals. The engine runs quiet now and I'm adding 2ozs ATF every oil change then 8 ozs 100 miles before I change it. I haven't added any more Lucas since the engine seems quiet without it.

Another side effect from using ATF is the oil consumption went way down. Car runs GREAT now.
Also now that the lifters are quiet you can hear cold piston noise at start up. It doesn't slap or knock, all you hear is a light rocking noise that's barely audible for the 1st 3 mins. When I think about all the BS the dealers shoveled out about piston slap I get pissed!

 

If you would have heard my engine before putting ATF in it you would have said SHUT IT OFF! It sounded that bad and these stupid effin dealers were claiming it was piston slap. It EFFIN INSANE. Personally I didn't believe them but wasn't sure what to do to solve the problem.

I noticed if I put heavier oil in it got much worse. I also noticed adding 4-8 ozs of ATF caused it to become dead quiet. Smoke that!

Now that I have the problem under control I'm just adding 2 ozs ATF at oil change and 8 ozs 100 miles before I change it. Now if it starts getting noisy again i'm going to just change the o ring and be done with it but so far(over 20k miles) its quiet.

 

Ok so when we all used to add ATF to our power steering pumps because its what we had on hand, what happened after time? The front pump seal failed because it swelled and got too soft. Adding the TransX or any seal stop leak isn't good. Its a temporary fix that will cause seals to fail in the end and need to be repaired.

I am not saying that it doesn't help stop lifter noise. Evidently it does for some reason. But it can cause another issue. Like the old saying of putting a band-aide on an axe wound. Its better to fix the problem instead of just covering it up.

 

Well the reason lifters quiet down is its properties allow it to enter the lifters and fill them, It also cleans them. Seriously the difference is increadable. Unfortunately the stock gm lifters are very touchy and seem to have zero tolerance for any kind of dirty oil. Hell they used these lifters in all their engines and honestly I just looked at a 01 Buick with a 6 cyl in it with the same issues. We put ATF in it and its quiet again, I've been doing this for years without any trouble.

My wifes 02 Formula had terrible lifter trouble at 28k, I dosed it with TransX and add small amounts of ATF and it ran great again. She drove it WITHOUT any leaks or trouble until 120k when a utility pole jumped out in frt of her and she totaled the car.

Trust me I would NEVER post up anything that I feel would cause more trouble to some ones car.

One thing I can tell you products like Rislone etc that claim to clean the lifters can cause BIG issues if the engine is sludged up. Friend of mine had a mid 90's Impala that had lifter noise, he bought it used. Put a qt of Rislone in it and a week later it wouldn't run, EVERY lifter was stuck closed and wouldn't bleed off. No compression!

I've never had ATF cause anything like that.

The one that really threw me was this EFFIN piston slap BS. Once I realized it was all BS and all the real noise was the o ring and lifters I just applied what I've used in the past to quiet the lifters. What really messes with you on these newer engines is aluminum sounds so different than cast iron engines. Plus the dealer network is so full of misinformation. The o ring and lifters are the 1st places to look on these engines if they clatter cold. Piston slap IF YOU HAVE IT is so different and its only 1 cylinder or so that IF you did have it would sound like a single knock, not a clattering tapping noise.

I've learned the hard way with the LS1.

 

thank u very much fo post da results of dat rattle n clacking noise,
I have da exactly same sound n at da exactly at da same rpm wen letting of da throttle at 1500 rpm
so, da o-ring pick up tube needs to b replace n anything else dat needs to b replace?

thank very much!

 

​​​​​
alright I will go n put TRANSX n ATF in my engine
big relief it's not piston slap ! Yay!