z28_n_tx

iTrader: (7)

ok ...i've been throught thisbefore, but i came across this http://www.pistonslap.com/ ... wish i had know about the 4k-6k value decrease at trade in..other wise i would of offered way less than what i payed for it...i've hearded that its normal for ls1 engines to do it and that there is nothing to worry bout...is this true???? i know my car has it for sure, when i first strat the car it does it up untill it warms up. but even then you can hear it not as loud though.

camaroextra

iTrader: (10)

propaganda! i duno what does it sound like, i get the usual valve train noise

z28_n_tx

iTrader: (7)

ummmm its sorta like a knocking noise...like isaid it only does it when i first start the car ..but if you give it gas you can hear it go faster..untill you let it warm up.

Zymosis

iTrader: (7)

gm claims its normal yes, which boggles my mind

Camaroz

iTrader: (2)

i have a little bit but it goes away after about 10 seconds..

z28_n_tx

iTrader: (7)

so is it normal??? and not something to worry about??

Camaroz

iTrader: (2)

I wouldnt say normal other than it is normal for GM V8's since way back... Don't worry about it it's just a annoying

Benjamin Russick

iTrader: (1)

If the noise goes away after warm up and you aren't using like 2 quarts of oil between changes, I wouldn't worry about it. I've had "slap" in other cars with no problems and they weren't even GM vehicles.

Mr Incredible

It is fairly common for LS1s. It hasn't been proven harmful except in the most extreme occurances, and we don't hear much about those.

I have a little when it's cold, and it only lasts for a minute or two. After that the pistons are warmed up enough to stop making noise.

I've changed to 5w-40 Mobil1 and it still does it, though not quite as much as when I used 5w-30 or 10w-30.

I'm not concerned in the least...for what that's worth.

jrivera04

It is a regular occurance with an LS1. I have a new LS6 block that was replaced under warranty in 2004. It has slight "piston slap". It doesn't hurt anything. But it does sound annoying. It reminds me of a deisel engine a little when it fires up. I believe pro stock cars have it but you can't hear it because its so loud.

Switching to forged internals will get rid of the piston slap from what I've read.

z28_n_tx

iTrader: (7)

thanks guys..it is annoying..hopefully when i get my lt's they will help with that prob

z28_n_tx

iTrader: (7)

forgot to ask.. is the value decrease true..do to piston slap???

chrs1313

iTrader: (24)

my car slaps real hard, when it starts up it sounds like there is a washing machine with marbels in it, i am not joking it is straight desiel...It is normal and my car runs strong as ever, dont worry about it.

B-MAN

Just about all LS1 based motors, 5.3,5.7,6.0,etc..., get piston slap. I put 64,000 miles of hard core beatings on my Trans Am since new and no problems. The only reson I rebuilt my engine, was because I needed big boy stuff in it, so that I could keep beating it up at the track!!!!!!.

My 2004 Silverado 2500HD also has had piston slap since new, and it now has 39,000 miles on it. Still runs like a dream. Love this desgin of motor so much, that I am thinking of adding a new GTO to my collection.

99PontTA

mine does the same thing..its nothing to worry about UNLESS it does it hot...then its a problem

narc

mine slaps even when hot...just not as loud...runs strong as ever

ULTIMATEORANGESS

iTrader: (4)

its not a problem.



for once GM is telling the truth.

99PontTA

hot slap won't hurt the running but its an indication that piston is too loose in that one cylinder....probably won't cause a big problem but its possible....get it???The idea is to get the pistons fitted loose enough they won't seize if you suddenly heat them up but tight enough that they don't scuff and slap.

Benjamin Russick

iTrader: (1)

Forged pistons will "slap" more because they take longer to warm up and get snug in the bores. Both of my old 5.0s were slightly noisy from the factory because of this effect. The LSx pistons "slap" because of the short piston skirt and high wrist-pin placement. Some blocks got uneven sleeves and those are the ones with the problems.

Humvee z28

ahh yes the wonderful piston slap. no it is normal. usually anything with a higher compression will have it, it is because of the tight/small piston to valve clearence. the dodge hemi's have it also. dont worry too much about it and just watch the oil level to make sure. my car does it a lot more when it is cold out like it is. in the summer in warmer weather it isnt as noticeable.