Whats the deal with "Piston Slap"?

[Marc 85Z28]

wow, i was expecting you to say like close to 200,000 miles or something.

Yeah. As impressed as I am with the LSx platform, it seems that unlike their predecessors, they're a hit or miss deal when it comes to modifications and durability. My Z28's engine has been going strong for nearly a decade now, with no oil consumption, piston slap, or spun bearing problems that plague the LS1s. I experienced all 3 within the first two years of ownership of my LS1 car The new engine however, is MUCH better

[oreowizard]

all my problems started with a spun bearing. We rebuilt the motor and now I have the slap.

[INMY01TA]

You're in Crofton right? If you feel like stopping by the Severn area sometime I'll disprove your comment You can actually see where the #1 piston was rocking in the bore, wearing the liner. Not coincidentally, all my piston slap noise in that engine was traced to the #1 or #3 cylinder with a stethoscope.

To the OP, if you still hear the same noise when warmed up during acceleration, you may have more than just piston slap. A damaged oil pump pickup o-ring will cause oil aeration and cause a VERY similar noise. GM issued a TSB for this.

So you're saying that the wear in cylinder #1 was caused by starting the car and immediately driving off instaed of warming it up? Piston slap is harmless if you warm it up 1st?

[Marc 85Z28]

So you're saying that the wear in cylinder #1 was caused by starting the car and immediately driving off instaed of warming it up? Piston slap is harmless if you warm it up 1st?

Sounds weird does it not? It's just really hard to overlook the facts in my case: I traced the noise to either the #1 or #3 cylinder. I only spent time trying to diagnose the noise because it was louder than most, enough to concern me with ruling out other potential causes. After pulling that engine for various reasons, the marks left behind on the cylinder liner of the #1 cylinder just could not be overlooked. That was the ONLY problem found. No piston/skirt or valve issues, no rod (on cylinder #1 anyway ) or wrist pin issues, no bearing problems. I am no super badass engine builder, but I know my stuff. That wear was quite obviously caused from a piston rocking in the bore. And we all know that pistons rocking in the bore causes the slap noise, so I added 2 and 2 together...

[INMY01TA]

Sounds weird does it not? It's just really hard to overlook the facts in my case: I traced the noise to either the #1 or #3 cylinder. I only spent time trying to diagnose the noise because it was louder than most, enough to concern me with ruling out other potential causes. After pulling that engine for various reasons, the marks left behind on the cylinder liner of the #1 cylinder just could not be overlooked. That was the ONLY problem found. No piston/skirt or valve issues, no rod (on cylinder #1 anyway ) or wrist pin issues, no bearing problems. I am no super badass engine builder, but I know my stuff. That wear was quite obviously caused from a piston rocking in the bore. And we all know that pistons rocking in the bore causes the slap noise, so I added 2 and 2 together...

Please re-read the question.

[02blkws6]

Mine sounds like a diesel when cold and a sewing machine when warm. That is the norm for the LS1. I have had 2 different cars. My 1st was an '02 and the 2nd is a '00.

[Marc 85Z28]

Please re-read the question.

There's 2 questions there, one of which is a two part question. I'm not sure what the second one is asking. If you think you know better, I invite you to stop by and look at the engine and give me your opinion. I'll bring it to your front door if you like.

[INMY01TA]

There's 2 questions there, one of which is a two part question. I'm not sure what the second one is asking. If you think you know better, I invite you to stop by and look at the engine and give me your opinion. I'll bring it to your front door if you like.

Both the same question really. You answered neither. In post #16 I quoted Shady saying it's a myth that not warming up your car before driving off is bad for it (it aint) then you went off saying your engine was damaged. I asked if it was damaged by not warming it up and you never answered. I assume you feel it was damaged by piston slap which wasn't what I was talking about and is another issue. So I'll ask you again:
Was your engine damaged caused by continuously starting your car and driving off without warming it up?

[Marc 85Z28]

So I'll ask you again:
Was your engine damaged caused by continuously starting your car and driving off without warming it up?

I believe so. I have no idea how hard the engine was ran when cold before I owned the vehicle.

Let me ask YOU this:

Do you think a piston rocking in the bore on cold engine and running it hard is a good thing? You claim it's not!? And finally, the more important question: Do YOU let your engine warm up before you drive off?

You need to stop assuming the car was started cold and gently driven until warm. Someone stupid enough to drive off immediately after a cold start is stupid enough to run the engine hard

[INMY01TA]

I believe so. I have no idea how hard the engine was ran when cold before I owned the vehicle.

Let me ask YOU this:

Do you think a piston rocking in the bore on cold engine and running it hard is a good thing? You claim it's not!? And finally, the more important question: Do YOU let your engine warm up before you drive off?

You need to stop assuming the car was started cold and gently driven until warm. Someone stupid enough to drive off immediately after a cold start is stupid enough to run the engine hard

I didn't assume anything about your car, I wasn''t even talking about your car. I also did not claim running an engine hard with a rocking piston while cold is fine. I said there is nothing wrong with starting your car and driving away (not hard) while cold. There isn't.

[Marc 85Z28]

I didn't assume anything about your car, I wasn''t even talking about your car. I also did not claim running an engine hard with a rocking piston while cold is fine. I said there is nothing wrong with starting your car and driving away (not hard) while cold. There isn't.

Are you a politician or something? What are you saying then? All I said is that in my engine, I believe that the piston slap caused the increased wear. The evidence is all there and quite obvious. I'll take my first hand evidence over an internet opinion.

And I'll ask again: Do you warm up your car before driving off?

[INMY01TA]

Are you a politician or something? What are you saying then?

And I'll ask again: Do you warm up your car before driving off?

No I dont warm my car up. What I am saying I was saying to shady, not you. Why you butted in with your piston slap damage story I still dont understand. I said it's a myth that not warming up your car before driving it causes increased wear. Lots of guys over on BITOG have proven this with oil analysis and such, Patman for one.

All I said is that in my engine, I believe that the piston slap caused the increased wear. The evidence is all there and quite obvious. I'll take my first hand evidence over an internet opinion.

I disagree with this anyway, I have piston slap, always had, so have thousands of others. No problem here.

[oreowizard]

I didnt know I would start all this by asking a ?

[Marc 85Z28]

No I dont warm my car up.

Thanks. That's all I needed to know. Good luck with your engine and especially your springs

[INMY01TA]

Thanks. That's all I needed to know. Good luck with your engine and especially your springs

Better luck than you I hope...

[INMY01TA]

http://forums.corvetteforum.com/show....php?t=1953723
A little info for ya. Read post #46 from Patman. He knows more about engines, engine oil, and maintenence then anyone around here. Idleing a cold engine is just wasting gas. Start and drive easy till warm is the best method.

[JoshieDoom]

Alright... heres my opinion..
Since the early days of vehicles poorly made parts required a warm up. I know my flathead jeep HAS to warm up..or it will not run worth a damn. I believe that the poorly manufactured engines had to warm up and seat rings and guides and valves for them to properly work and without this EXTREME wear was caused. I believe this has been passed down into the mindset of people. BUT... and i emphasize BUTTTT. If you drive the balls outta a cold engine while it a piston is smacking around.. HOWEVER minut the movement, it will cause more rapid wear and tear on the engine. If the driver races a cold engine when he knows he has a piston smacking around then it will lead to a bad ending and a rebuilt engine comming soon. Ive seen lots of old people set in their ways and they were told the incorrect information when young and not corrected in time so it became set in stone..
1. More engine wear will be caused by not warming up a vehicle.
2. Piston Slap is causing excess wear.
3. If you let it warm up for just a minute piston slap should be just an annoying noise.. and thats all.

I let mine warm up about a minute and then baby the piss outta it until it gets around to operating temperature.

[INMY01TA]

Alright... heres my opinion..
1. More engine wear will be caused by not warming up a vehicle.

Running an engine cold period causes engine wear. Ideling a cold engine prolongs the warm up. Engine warms up faster under load.

[JoshieDoom]

They also wear faster under a load when not properly warmed up..

[INMY01TA]

They also wear faster under a load when not properly warmed up..

oil analysis show otherwise.....