piston slap is the noise generated when the piston hits the cylinder wall. this happens because the gap between the wall and the piston is large when the engine is cold but disappears when the engine warms up and the parts expand from the heat. the noise will also drop off as oil circulation increases after the first few seconds past start up.

it's not damaging to the engine, just annoying. some ls1s do it, some dont...mine never has (knock wood).

 

So you guys are saying that my issue is "piston slap"?

In most cases, I read that piston slap goes away when the car warms up, is that right? Mine never goes away. It's there regardless of all outside temperatures and the operating temperature of the vehicle. It never gets louder and it never gets quieter. It's just a constant really light ticking noise as the RPM's rise and fall.

 

you may have a exhaust leak.

 

Where at? Where the headers meet the engine?

I just had B&B Bullets installed last week, everything is as tight as can be. Sound is still there.

Noises like this sure are frustrating.

 

I guess I'm lucky, my engine was silent untill I installed a LS6 intake with out the foam pads on it. Now I can hear the injecters echo through the intake but it will get fixed soon. A few things that make LSX engines make noises, hmm lets see. Noisey valvetrain, piston slap, belts, and belt tensioners. Just thank god you dont own a 6.0 truck that sounds like every lifter is ticking from the factory. Oh BTW I would not spray **** into my engine even if it did give me 100HP

 

Mine's done it since I drove it from the dealership in 02. It goes completely away after she's warmed up. 44k on it now and no problems. It's just an annoyance. I know they are out there but I have yet to see one in person that hasn't had it. They are fortunate.

 

My 00 WS6 has it....it's more of a knock and not a tick. it goes away in a minute or two.

 

do you have headers or manifolds? if you have headers than they might not be tighten down right you have to start from the middle and work your way out to the ends. or they may have came loose after a wile

 

To me, piston slap sounds more like a light knock than a ticking. If it goes away (or at least gets a lot better) as the engine warms up (about 10 minutes), then it's most likely piston slap. If it sounds the same warm or cold, then you've probably got an exhaust leak or a sticking lifter.

 

 

My dad's 2000 silverado 2500 does it sometimes. He is still driving it with 200,xxx miles on it. My 5.3 doesnt do it. I guess its a hit and miss kinda deal.

 

piston slap is normal........it should sound like a diesel when its cold but any abnormal ticking or pinging should be looked at

 

diesels sound WAY different trust me. my dad has his own big rigs. they dont sound anything like piston slap.

 

I always thought piston slap on lsx cars sounded a little bit like diesel pick ups

 

piston slap

 

not time to tear it down. When u throw a rod, thats when its time. Completely normal. Most GMs do this from the day they were born. Dont worry about it man

 

most lsx engines experience PISTON SLAP. short piston skirts at the problem, i believe. one vehicle's being worse than anothers is simply in the build tolerances. same reason some stock ls1 cars haul *** and others are boat anchors. i can think of 7 ls1 cars off the top of my head that have that problem. 3 of them are making serious power, 2 have over 150k on them, and 0 have had any problems. hit it with the n2o, you'll like it.

also - my car made the noise regardless of what oil is used. i went through all kinds just to see what was bs.

 

hey quickshift the same thing happens to the suburban with the 8.1liter engine or at least some of them. i can hear it when rpms go up and down. i just figured it was piston slap plus the fact its in kuwait and i thought the 120* weather destroyed the engine haha

 

Yeah maybe big CAT or Cummins motors but that's because those are inline large displacement engines. Piston slap will sound like an LB7 Duramax or a 7.3 Powerstroke. Our 5.3 Tahoe sounds the same as our 'stroke when it's cold due to slap. And trust me we have 6 diesel rigs ranging from a lil 3 cyl wheel tractor to a tractor with a 3306 and many other large diesels including a Cummins and International... So trust me

 

Don't worry about it. It My 5.3 has done it for the 170k+ miles I have put on it. Sometimes sounds terrible like a diesel sometimes not. Sometimes a light tick when warm sometimes not. I doubt switching to RP oil will help it because what is happening is the very short piston skirt(to eliminate weight) allows the piston to rock back and forth as it is moving up and down in the cylinder. Carbon build-up on the piston contributes to this. Many have temporarily eliminated or helped the problem by "Seafoaming" their engine through the PCV or brake booster. I am surprised nobody has mentioned this yet. There is a whole website devoted to this and they tried to get a class action lawsuit against GM about it. It is bookmarked on my other computer and their slogan is " GM, like a knock" My 5.3 has used a little oil since new I believe because of the looser tolerances which causes the slap but my 5.7 is tighter and has no slap or oil usage. Use of top tier fuel (google it if you don't know what it is) will help too. Spray itlol