View Full Version : Piston Slap


Bigbrut01ws6
01-18-2010, 05:35 PM
Whats the deal with piston slap, should i be worried about my car??

TA_BUD
01-18-2010, 08:01 PM
does it only do it when in gear, then its slapping

araber89
01-18-2010, 08:57 PM
Most LS1's make noise actually my LQ4 in my truck does too. Its something you get used to. Keep an eye on it but usually quiets down when it warms up but still there.

BlackScreaminMachine
01-19-2010, 07:02 AM
It's common, do not worry about it.

If the car is fully warmed up, in Closed Loop and showing Knock Retard on a scanner, then I would start looking. There are cars out there that sound like a Diesel.

RPM WS6
01-19-2010, 10:19 AM
My '02 car slaps pretty well, even when warm. 96k miles and no problems though, rarely burns a drop of oil.

I just live with it.

TurdsOfMayhem
01-19-2010, 10:35 AM
Mine only does it when it is really cold, sounds like a damn diesel, even after it warms up. After a good 45+ mins of driving, it is almost completely gone. But like this morning it was warmer than it has been, and barely had any noise at all.

My Formula did the same thing, and this is my 2nd LS1, so I'm sure it is common. Though my uncles Z28 doesn't do it, fiances fathers vette doesn't do it... Just my luck. LOL

xTraViSx
01-19-2010, 12:07 PM
If you start getting piston slap its ok. Just make sure your car is good and warm before you romp on it. Ive had 2 LS1's. Both have/had it. Both were/are daily drivers. Piston slap sounds a little ruff when you first start it up. But, other then that it hasn't caused any other issues.

99NBMT/A
01-19-2010, 01:10 PM
What causes them to do it? This is my first LS. It doesn't do it, What if it starts?

ULTIMATEORANGESS
01-19-2010, 02:04 PM
both my cars have it. im not concerned.

Bigbrut01ws6
01-19-2010, 04:51 PM
It does it when i first start it up then gets a little quieter but never really goes away.

RPM WS6
01-19-2010, 05:58 PM
It does it when i first start it up then gets a little quieter but never really goes away.

Sounds just like my '02 car. But I'm not worried about it. MPG is great, power is great, and there is no significant oil consumption.

My '98 is slap free though. My '99 and '00 were also slap free. Just the luck of the draw I guess....

transbiulder24
01-19-2010, 06:19 PM
my 02 z28 ticks like crazy when warm,then is intermittant.long trips it does it all the time,i thought it was a lifter?what do yall think?no oil consumption either. but i cant stand it when people stare,damn!

Bigbrut01ws6
01-19-2010, 06:34 PM
thanks for the opinions i feel a little better about it now.

chadaclysm
01-19-2010, 08:50 PM
My car does it, but only when cold. It is gone before the car is even fully warmed up. It is an '01 with 100k miles.

Ironxcross
01-19-2010, 09:01 PM
I like my piston slap. It lets me know I'm driving an LS1.


Then again it only does it when it's colder than 40 degrees out.

gta3uzi
01-19-2010, 09:25 PM
Mine does it in the morning. If I start it and immediately leave when it's about 30-40*f outside, the slap is usually gone before I've gone 1000 feet.

00blacka4
01-19-2010, 10:00 PM
mine has it a little if you start it up and put it right in gear you can hear it...but if its cold i just start it and hold it right before the rev limiter for like 3 minutes and it goes away.

FormulaWs666
01-19-2010, 10:11 PM
mine has it a little if you start it up and put it right in gear you can hear it...but if its cold i just start it and hold it right before the rev limiter for like 3 minutes and it goes away.

Theres a recipe for a blown up ls1...:nod:

gc302047
01-19-2010, 10:32 PM
mine has it a little if you start it up and put it right in gear you can hear it...but if its cold i just start it and hold it right before the rev limiter for like 3 minutes and it goes away.

your kiddin... lol

00blacka4
01-19-2010, 10:45 PM
no ? thats what someone told me to do...they said since the oil isint heated up the high rpms help it get to the tick and stop it faster so it doesent cause problems...

prokilllsx
01-19-2010, 10:54 PM
Nice car man. I am from Cinci also and used to run at edgewater and tri-state. Those are some decent times. What is done to your car?

baalic
01-19-2010, 10:56 PM
no ? thats what someone told me to do...they said since the oil isint heated up the high rpms help it get to the tick and stop it faster so it doesent cause problems...

you are kidding right?? Somone honestly wants you to blow your car up.. That "theory" holds true to diesel trucks especially with air brakes but NEVER just before a rev limiter or redline... if you ARE going to rev up the car to hold an idle...when its cold...I would NEVER go above 2000 rpms....and even that's a little much...1200-1400 is about all you would even rev it to if you want it to warm up faster but the smarter thing is to let it warm up in idle......

00blacka4
01-19-2010, 11:05 PM
lol alright funs over...no i never touch the gas until my car is almost completly warmned up...and i never give it WOT until its all the way warm...i was just having a little fun seeing what the comments would be. :nod:

baalic
01-19-2010, 11:23 PM
lol alright funs over...no i never touch the gas until my car is almost completly warmned up...and i never give it WOT until its all the way warm...i was just having a little fun seeing what the comments would be. :nod:


Well GOOD, but incase someone else reads this and thinks its ok I wont amend my previous post's lol

RPM WS6
01-20-2010, 12:27 PM
I find the best way to clear up piston slap is to keep the pedal floored while starting the engine cold, so as soon as the motor is running you're at WOT. Then, I instantly shift into gear while keeping my foot on the brake and gas, doing a massive burnout through 2 gears. I then release the brake and stay at WOT coming out of my driveway all the way till it shifts to 3rd (about 100mph). If there is traffic in the way, I just drive on the sidewalk. That usually gets rid of any slapping!

baalic
01-20-2010, 01:20 PM
i find the best way to clear up piston slap is to keep the pedal floored while starting the engine cold, so as soon as the motor is running you're at wot. Then, i instantly shift into gear while keeping my foot on the brake and gas, doing a massive burnout through 2 gears. I then release the brake and stay at wot coming out of my driveway all the way till it shifts to 3rd (about 100mph). If there is traffic in the way, i just drive on the sidewalk. That usually gets rid of any slapping!

+++++++++++++1

ULTIMATEORANGESS
01-20-2010, 02:45 PM
blowing up your motor is a guaranteed method of getting rid of piston slap. :bomb:

baalic
01-20-2010, 03:38 PM
blowing up your motor is a guaranteed method of getting rid of piston slap. :bomb:

Yup it can't slap if its gone boom....

ae13291
01-20-2010, 05:12 PM
so 97-2000 LS1 engines are build with tighter tolerance?

RPM WS6
01-20-2010, 07:40 PM
so 97-2000 LS1 engines are build with tighter tolerance?

In my experiance, the '01-'02 cars usually slap louder and are more prone to the issue in the first place.

I beleive there was a piston or ring change made in 2001. I suppose this might have something to do with it.

chadaclysm
01-21-2010, 11:16 AM
I find the best way to clear up piston slap is to keep the pedal floored while starting the engine cold, so as soon as the motor is running you're at WOT. Then, I instantly shift into gear while keeping my foot on the brake and gas, doing a massive burnout through 2 gears. I then release the brake and stay at WOT coming out of my driveway all the way till it shifts to 3rd (about 100mph). If there is traffic in the way, I just drive on the sidewalk. That usually gets rid of any slapping!

Thanks a lot jackass, you made me actually laugh out loud... I am in a quiet study room.

gta3uzi
01-21-2010, 11:23 AM
lol alright funs over...no i never touch the gas until my car is almost completly warmned up...and i never give it WOT until its all the way warm...i was just having a little fun seeing what the comments would be. :nod:

You made me nervous. haha

AmericanMuscleLS1
01-21-2010, 12:42 PM
I find the best way to clear up piston slap is to keep the pedal floored while starting the engine cold, so as soon as the motor is running you're at WOT. That usually gets rid of any slapping! LOL!

Ahem, these engines won't start at WOT, the injectors are turned off! DUH!:bang:

My 98' WS6 has a hint of slap when cold, and none when warm. She has
127k on the origional motor. I just ignore it, and let her warm up to atleast 160 before taking off. My fathers LQ4 slaps, but only on VERY cold mornings.

zacht
01-22-2010, 07:19 PM
so is the culprit with piston slap the piston rings? and more comonly 01-02 cars?

wondering, i have a 02 crate in my car with 25k, dont get any, but its a relatively new engine.

pewter2002
01-22-2010, 08:00 PM
I thought GM changed the type of rings, TIGHTENED the cylinder tolerences and coated the piston skirts for 2001 -02's to prevent scuffing (due to tighter tolerences) due to the customer complaints? GM High Tech brought up these technical improvements in its mag back in the day. GM still maintained that the piston slap was a customer satisfaction issue rather than a durability issue, as far as they were concerned (yeah, limit warranty claims) yet they saw fit to make the already mentioned improvements! Some of the improvements were made to combat "ring flutter" (and resulting oil consumption). After 2000 I thought piston slap was not an issue?

RPM WS6
01-22-2010, 08:49 PM
After 2000 I thought piston slap was not an issue?

I've noticed it to be the other way around. My '98-'00 cars were not slappers, but my '02 is a HUGE slapper. Other '98-'00 cars I've heard rarely slap as well, but I've come across several '01+ that do.

SOMbitch
01-22-2010, 09:04 PM
A little PS or CSK (cold start knock) as it is sometimes referred to hurts nothing in these motors. My 98 LS1 has none at all. My 196K 5.3 LM7 in the truck has had it since I bought at 87k and has no change in noise or oil consumption. It has always used about a qt. at 3k and never more and still runs like the day I bought it in 01.

It is caused by excessive piston to bore clearance causing the piston to rock until it heats and expands to fill the bore. Also these pistons. have short skirts to keep weight down and carbon builds on the skirt and makes it noisy. This why seafofam or a similiar treatment can help temporarily. Many forged pistons are also this noisey but with headers and aftermarket exhaust they never hear it or report it. I had a buddy with a Mopar 440 in a challenger built as hell and that thing was ugly sounding on cold start but could rape anything he wanted too when it counted......he ran it for years before we lost touch...It was the wristpin offset that made that car so noisy is my point.... DRIVE IT!!!

ULTIMATEORANGESS
01-22-2010, 09:04 PM
i heard LS2s have a piston coating to prevent slap yet i still hear it.

quadd2244
01-23-2010, 12:23 AM
98 ws6 here. 81k miles NO piston slap whatsoever. I also rarely burn a drop of oil and I have full bolt ons. Thankfully I guess I got a good one since I heard 97-00 ls1s have more slap then newer cars however I hear more 2000+ cars having more slap then 2000 or less lol. Hell my buddies 04 gto has under 30k miles and is a slapper

Mr.z/28
01-25-2010, 04:51 AM
My 2000 z28 does that when I turn it on a cold start. Rarely does it.
It then goes away when its warm.
Friends on mine says its common on F bodies, but nothing to worry.

the_merv
01-25-2010, 05:17 AM
A little PS or CSK (cold start knock) as it is sometimes referred to hurts nothing in these motors. My 98 LS1 has none at all. My 196K 5.3 LM7 in the truck has had it since I bought at 87k and has no change in noise or oil consumption. It has always used about a qt. at 3k and never more and still runs like the day I bought it in 01.

My 1999 Sierra 5.3 does the same thing if I havent driven it in a while..it knocks for about 5 sec and goes away.