Do all LS1 engines have the piston knock ? [Archive]

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SpeedAddict38

11-24-2006, 09:45 PM

Do all the LS1 engines have the piston slap at start up, that goes away ?

fast droptop

11-24-2006, 10:03 PM

My 98 didnt but my 01 does at start up some of the time. Goes away in a matter of mins

SpeedAddict38

11-24-2006, 10:16 PM

My 98 didnt but my 01 does at start up some of the time. Goes away in a matter of mins

ya thats the way mine does. I was worried at first lol

Y2KPewterSS

11-24-2006, 10:17 PM

I have had a pair of 2000 LS1's now and been fortunate that neither of them had the piston slap. :)

SpeedAddict38

11-24-2006, 10:25 PM

I have had a pair of 2000 LS1's now and been fortunate that neither of them had the piston slap. :)

will it hurt anything ??

SeVeReDiStOrTiOn

11-25-2006, 12:32 AM

I have it...goes away way before reaching op temp

djvaly

11-25-2006, 01:28 AM

make sure ur on 91 or 93.. else it would knock..

98Z-28Camaro

11-25-2006, 09:09 AM

Mine doesn't as of right now. 77k

KageSS

11-25-2006, 02:45 PM

make sure ur on 91 or 93.. else it would knock..

Higher octane doesn't have anything to do with it. :bomb:

KageSS

11-25-2006, 02:47 PM

will it hurt anything ??

You're fine. :yup:

djvaly

11-25-2006, 06:12 PM

Higher octane doesn't have anything to do with it. :bomb:

engine knock he is talking about right?

KageSS

11-25-2006, 06:15 PM

engine knock he is talking about right?

He's talking about tapping noise that lifters make on start-ups when Eng. is cold. I think.

I know he said pistons, but i think he meant to say lifters.

SpeedAddict38

11-25-2006, 07:36 PM

He's talking about tapping noise that lifters make on start-ups when Eng. is cold. I think.

I know he said pistons, but i think he meant to say lifters.

ya lifters knock on cold start then go away

AKIRA

11-25-2006, 07:39 PM

He's talking about tapping noise that lifters make on start-ups when Eng. is cold. I think.

I know he said pistons, but i think he meant to say lifters.

He got it right. The term is called piston slap. However, it isnt cured by higher octane as you said earlier.

Tyler_LS1

11-25-2006, 07:40 PM

LS1 have Hydraulic lifters right? it may be that one is sticking just a bit.
I know my Truck sticks a bit at a cold start.

KageSS

11-25-2006, 07:41 PM

ya lifters knock on cold start then go away

It's normal.
Some ls1's will make the tapping noise, some won't on start-ups. :yup:

Mine don't...... :nana:

Excessive piston slap occurs when the clearance between the piston and the cylinder bore is too great. The piston to cylinder bore clearance becomes too great either through wear, mismatched pistons and cylinder bores at manufacturing or, a combination of both. The audible noise associated with excessive piston slap is due to the perpendicular impact of the piston against the wall of the cylinder bore. Audible piston slap is typically loudest when the engine is first started up. The pistons then expand with heat reducing the piston to cylinder bore clearance thus, reducing the perpendicular impact of the piston against the cylinder wall and its resulting noise.

In the case of the famous GM piston slap engine defect, the piston design with hypereutectic (high silicon content aluminum alloy) pistons, reduced or eliminated piston skirts (to reduce reciprocating mass), and a higher ring pack to reduce unburned fuel mixture on the sides of the piston crown have made piston to cylinder bore fit much more critical. The amount of tolerance (variation or margin) in allowable clearance between the piston and cylinder bore to prevent audible piston slap has been reduced by a factor of at least 50%. Consistently hitting the narrower margin for piston to cylinder bore tolerance has not happened for GM during mass production. Thus, some engines have no audible piston slap and some have piston slap on only one or two cylinders. What might have looked really good in testing of hand built engines in the lab hasn't transferred to the production line of this corporate giant.
Make no mistake about it, while a lot of these engines don't appear to be driving rods through the blocks, the ones with louder and longer duration piston slap will wear out before the ones that are basically quiet. The perpendicular heavy impact of the piston against the cylinder wall over time will not come without a price. This is also why GM has released a recent TSB saying that opening 4 quarts of oil to add to your crankcase between a 7,500 mile recommended oil change interval (1 qt per 2K miles on an engine with 36K miles or less is "NORMAL". After 36K miles, all bets are off (there is no abnormal oil usage rate). This is why the now common offer of an engine component letter extending your warranty to 5 years or 100K miles is basically worthless. If the piston isn't laying in the oil pan in pieces, the engine will be operating "NORMAL" according to GM

KageSS

11-25-2006, 07:55 PM

Like i said before, it doesn't have anything to do with the octane rating people. :cuss: :)

djvaly

11-25-2006, 08:00 PM

Like i said before, it doesn't have anything to do with the octane rating. :cuss: :)

aha, yeah I see, I thought u are just having knock problem, piston slaping
not sure mine does that,,, probably until the engine warms up, maybe it has to do with the starting temperature of the engine until it gets to warm level.
like here in TX it doesn't dip below 40 usually. but in Colorado it dips to 15-20F so it may start piston slap at that low of temp. not sure. mine doesn't do it.

KageSS

11-25-2006, 08:08 PM

aha, yeah I see, I thought u are just having knock problem, piston slaping
not sure mine does that,,, probably until the engine warms up, maybe it has to do with the starting temperature of the engine until it gets to warm level.
like here in TX it doesn't dip below 40 usually. but in Colorado it dips to 15-20F so it may start piston slap at that low of temp. not sure. mine doesn't do it.

I don't have that problem. You have me confused with someone else. And i'm from Texas also....... :rock: :D

djvaly

11-25-2006, 08:16 PM

I don't have that problem. You have me confused with someone else. And i'm from Texas also....... :rock: :D
ayy. u are right,, TX pal, I'd like to piston slap that avatar of urz. :)
I know ur from TX I was just making a point, other people like in Colorado etc may experience it more often,, I dunno

Tyler_LS1

11-25-2006, 08:23 PM

ayy. u are right,, TX pal, I'd like to piston slap that avatar of urz. :)
I know ur from TX I was just making a point, other people like in Colorado etc may experience it more often,, I dunno

:nono: I think that HIS girl.
LOL

djvaly

11-25-2006, 08:25 PM

:nono: I think that HIS girl.
LOL

oops, lol

KageSS

11-25-2006, 08:28 PM

It's all good, i'll piston slap her later for ya. :D

djvaly

11-26-2006, 03:10 AM

hahahhaha.. more piston "power" to you! :)

George141

11-26-2006, 08:17 AM

...you may want to experiment by plumming a coolant heater or plug in your engine block...(if you have one)..and see if that makes a difference..these engines are mild racing engines right off the show room floor so it's possible the clearances are a little loose....allways let them warm up before driving them and there should be no issues.....and like others say it clears up...

COYOTE SS

11-26-2006, 04:49 PM

I have it and it doesn't go away once the car warms up. It seems to have gotten worse since the day I bought it ( with 1,900 miles on it ). I put some Sea Foam ( I don't know if that is how it is spelled ) in it and got a Dyno-Tune, that help briefly. I'll try the Sea Foam again next Spring.

A~NICE~CAR~IS~A~NICE~CAR

11-26-2006, 05:33 PM

same here, it stays till its warm, sounds like a sewing machine.....

djvaly

11-26-2006, 05:37 PM

what do the tech people at the shop say?

COYOTE SS

11-26-2006, 05:44 PM

what do the tech people at the shop say?

Who are you asking?

98Z-28Camaro

11-26-2006, 06:45 PM

Piston slap is not the hydralic lifters tapping. That noise is called the hydralic lifters tapping. Piston slap is where the piston actually rocks in its bore (like a rocking chair) until the temperature of the cylinder (piston and wall mainly) reach operating temperature as which point they expand to correct tolerances and it quits rocking in the bore. It almost sounds like a rod is knocking. The tapping noise (light sounding, not a lower toned tap) is just the lifter to pushrod, or pushrod to rocker arm or rocker arm to valve stem being out of adjustment. Neither of which are a huge deal, but should be repaired as soon as possible in my opinion. But the piston slap probably doesn't need to be worried about until an overhaul or the engine fails. Just my .02 cents.

djvaly

11-26-2006, 07:33 PM

Who are you asking?
Coyotee SS: for u :yup: .. so the dyno tune shop people said..?

COYOTE SS

11-26-2006, 11:25 PM

Coyotee SS: for u :yup: .. so the dyno tune shop people said..?

I had Doug Rippie up in Minnesota tune it and he said it was a lifter sticking and to use Seafoam. I used half a can with half a tank of fuel, this spring I'll use a full can with a full tank.

z28punk

11-28-2006, 09:20 PM

im a newb to ls1's still. can someone post a sound clip of the piston slap noise? or is it to quiet to record?

djvaly

11-28-2006, 09:36 PM

www.xxx.com/sounds :lmao:

z28punk

11-28-2006, 09:46 PM

sounds a lot like that 07 Z06 i drove at the dealership. lol

MissingMyZ

11-29-2006, 02:43 PM

Gm aknowledges the noise but has stated that it has not been proven to cause premature engine failure.

9t8z28

11-29-2006, 03:34 PM

Our engines are aluminum! (Different expansion rates than steel) Its normal!

slpws6ta

12-31-2006, 01:24 PM

where you live has nothing to do with it i live in southern florida and my car has piston slap operating tepm is operating temp no matter where you live. It may take longer for piston slap to go away for people in cooler climates but operating temp is still 210 if it's 100 out you can still get piston slap

9t8z28

12-31-2006, 03:00 PM

djvaly

12-31-2006, 03:10 PM

Well then it does have something to do with where you live!

when it's cold out like 30s below I mean, coupled with higher altitude (less air density) as well then the engines tend to knock a bit. my 2 cents.

bttb

01-03-2007, 04:41 PM

My ss has lots of piston slap. It takes a long time after start up for it to quiet down. When weather is cold the more noise it makes.

GatorSS

01-04-2007, 12:05 AM

Mine does not have piston slap.

SSTODD

01-04-2007, 09:58 AM

Try a different oil and/or a different weight as some oils make the sound worse. Mobil 1 is very thin and makes more noise IMO.

ShelbySS

01-04-2007, 10:00 AM

Try a different oil and/or a different weight as some oils make the sound worse. Mobil 1 is very thin and makes more noise IMO.
So what is the best oil for an LS2?

I used Mobil 1 in my LS1...

ShelbySS

01-04-2007, 10:01 AM

im a newb to ls1's still. can someone post a sound clip of the piston slap noise? or is it to quiet to record?
You'd know if you heard it...

SSTODD

01-04-2007, 10:09 AM

Sarge is the oil guru but I believe he had good things to say about royal purple so I'M going to give it a shot this spring when I pull it out of the garage

jad628

01-04-2007, 10:44 AM

No slap here. 74K +.

shady milkman

01-04-2007, 10:49 AM

gm fixed the problem in the ls2 up engines. they switched to a floating pin design for the piston heads. its normal, really no problem with it, just dont go street racing before it goes to op temp. there that was my bit of information :coffee:

ShelbySS

01-04-2007, 10:49 AM

shady milkman

01-04-2007, 10:50 AM

My ss has lots of piston slap. It takes a long time after start up for it to quiet down. When weather is cold the more noise it makes.

yea once it reaches op temp it goes away, if it doesnt then you got a problem.

shady milkman

01-04-2007, 10:53 AM

So what is the best oil for an LS2?

I used Mobil 1 in my LS1...

there are better oils out there. rp is good. um that castrol shit from germany that is pure synth. throw sarge a pm and he will help you. but dear lord for oil filters..stay away from FRAM!!!!!! that is for all members.

SSTODD

01-04-2007, 11:14 AM

there are better oils out there. rp is good. um that castrol shit from germany that is pure synth. throw sarge a pm and he will help you. but dear lord for oil filters..stay away from FRAM!!!!!! that is for all members.

Where the hell is shepard,MI:dunno:

shady milkman

01-04-2007, 11:21 AM

Where the hell is shepard,MI:dunno:

:lol: its about 5 miles south of mt.pleasant. and about 45 mins north of lansing. right of of 127

SSTODD

01-04-2007, 11:31 AM

Thanks man, that a long haul from Livonia but I did learn something today.:yup:

shady milkman

01-04-2007, 11:35 AM

Thanks man, that a long haul from Livonia but I did learn something today.:yup:

:yup: :nana: then its a good day.

OnEbAdReDSS

01-04-2007, 11:53 AM

Hey is piston slap created by the pistons and engine block not being 200 Degrees because i know chevy before it bores out its blocks heats the engine up to 200-210 where ever the optimum temp is... soo is that it??

shady milkman

01-04-2007, 11:58 AM

shady milkman

01-04-2007, 12:13 PM

the slap is caused by the piston and clyinder bore is to great. so the piston travels off its up and down motion and goes more side to side, durring the up and down motion, so the piston "slaps against the clynider wall. the reason why the "slap: goes away durring op temp or close too. is becuase the ls1 pistons are made of a aluminum alloy. so as the temp increases the alloy expands which then eliminates the piston :wtcslap:. so yea its becuase of the build tolerances that some ls1s have no :wtcslap: at all and some do. its like a +-.001 build tolerance. :nana:

Frankthetank

01-06-2007, 09:33 PM

both mine do lol

hehe its cool man get used to it...it wont go away......Especially if u upgrade the valvetrain

OnEbAdReDSS

01-08-2007, 09:09 PM

I got used to it my dad thinks its one of my rockers knockin soo i told him if he dont' believe me then hey by me some SLP 1.7 rockers! :)

shady milkman

01-09-2007, 05:29 PM

I got used to it my dad thinks its one of my rockers knockin soo i told him if he dont' believe me then hey by me some SLP 1.7 rockers! :)

shit show him this thread.