so my car was makeing a tapping, knocking sound on cold starts and the noise would fade off as the engine would get warm. i checked the oil no problems there and the car has low miles so i just couldnt belave it had a bearing issue. my one buddy is a gm tech and told me the ls1 has a problem with piston slap. is this true. and if it is have any of u had any issues with this before and if i do have piston slap does that mean its time to tear her down and rebuild.... thanks

 

yes thats normal. what you are hearing is it a ticking? all of them do it. nothing to worry about. unless it isnt stock than you need to check your piston to valve Clarence

 

no it not a ticking it is more of a knock for the first id say 5 sec when i cold start it then it fades off pretty good

 

whats done to the car?

 

my car does it do! i hate it! i can really hear it with cutout closed. It compleatly goes away once car is warm..but it annoys me when car is cold. people think its something wrong with my car. i tell them naw its normal. its called piston slap. and they look at me like i just called them an ******** or something..lol.. why do they do this?

 

My '98 Vette has a little of it too. It's NORMAL on most LSx based engines.~Cole~

 

the car has slp intake and slp catback with punched cats i have a nitrous kit sitting at my garage but i didnt put it on cause of this problem what do u think

 

spray the problem away!

 

what helps out with alot of people is change to royal purple 5w30 it almost eliminates. i dont have it. but iv ran RP since i had it.

there is a thread on this to just search for it.

but try that and see if that helps

 

o really? hmmmm.. if royla purple can get rid of it..then royal purple is what ima be running...its a pretty respected oil aswell anway...

 

so u think im safe to spray im doing nitrous outlet 100 dry ****

 

i would do a compression check first.

 

**** or shot?

 

so piston slap can cause a loss of compression?

 

it could. but its a really good thing to do before running nitrous on any motor, and you really want to do it with high milage engines

 

ok man thanks for all your help

 

I have a 99' FRC Vette that has had a problem similar to this from the day I bought it. I have been told by numerous people that the LS1 just sounds like that and not to worry about it, but I haven't been able to stop worrying about it since day one.

Mine is a very light ticking noise. It's like a baseball card in the spokes of a bicycle. The intesity of the ticking increases and falls with RPM. It's never got louder, it's never got quieter. I've owned the car over a year now, and it's done it the entire time. It dyno'd at 312rwhp(SAE) with only B&B Route 66 exhaust. I'm about to the point where I'm going to bring it to a local Chevy dealer and see what they think, I just don't know.

How does one come to a final decision of whether or not this is a HUGE problem without tearing down the entire motor to carefully inspect every single part?

 

its normal

 

Really?

What causes this noise?

 

Lifter?? That what i thought mine was, and i just noticed it in the last month, but i'm doing heads and cam soon so i didn't worry bout it