Piston Slap?

[sjsotelo]

I took my car in and had the timing belt stuff done, you know, timing belt, all drive belts, waterpump, oil seals, all that jazz..

Well i also asked him about this noise i get when i first turn the car on and start driving. Its a clicking noise, and it only happens tell the car is warmed up. The guy said it was a "Piston Slap" and it just means the car needs to warm up more. I dont remember having this 2 months ago, is this a problem? or something that I should just ignore?


-Stephen

[Turbob20EG]

Can you tell where it is coming from head, block, or what? Pistons shoudn't "slap" far as I concerned piston noise is not a good period. Think about what is happing.. Besides that, I would look into mech's rep. If you take your car some where to do anything it shoudn't come back making new noises. I mean they tell you about problems already had that might not known and should have said something about new noise before you started it. To me seems little shady waiting till you asked bout it.

[Hybrid_Coupe]

piston slap is normal for a forged motor...my motor does it and has done it since i built it the first time...(.003" clearance for high rpm forged motor.) if its a stock motor...their should be NO piston slap...that means you have excessive skirt wear...or a broken skirt.

[sjsotelo]

its a stock d16y7 baby! so piston slap is bad for me eh? next qustion, whats a skirt? lol

[Hybrid_Coupe]

the piston skirt is what stabalizes the piston in the bore...its exactly what it sounds like its a skirt that goes down a little ways...i dunno how to explain it...but anyways...yes...piston slap for you = a bad thing

[Turbob20EG]

I didn't know that bout sleeved high rev'ers. Ya always teaching me chit 98EX. Only forged stuff I deal with normaly is old american stuff. It seems like would still be bad thing thou, but that just from thinkin what is actualy going on in there.

[dubcac]

Piston slap can also occur if the cylinder bore is slightly larger than the piston, and the piston slaps the wall. For instance, if the cylinder wall gets honed a little too much and not measured/toleranced.

[Hybrid_Coupe]

we use extra clearance because forged aluminum expands at a different rate than cast aluminum. when my motor is dead cold, my pistons will slap for about...10minutes...by the time the fan comes on...i have no more piston slap...now there are several things that happens there...oil coverage, heat, and obviously a rpm change from warm up to normal idle. After 2 years of using the same pistons, i have no signs of skirt wear. the tolerances were set to cp specs. Now trust me...my car fully warms up before i even move it, let a lone race it, so i dont race it with piston slap. that would probably cause major problems, but i dont want to find out...piston slap in a forged motor is normal..you probably just cant hear it through your cast iron block and by the time you do hear it, your right, it probably is a very bad thing.

[sjsotelo]

<div class='quotetop'>QUOTE(Resistance98EX @ Apr 6 2006, 04:12 AM) [snapback]100784[/snapback]</div>

we use extra clearance because forged aluminum expands at a different rate than cast aluminum. when my motor is dead cold, my pistons will slap for about...10minutes...by the time the fan comes on...i have no more piston slap...now there are several things that happens there...oil coverage, heat, and obviously a rpm change from warm up to normal idle. After 2 years of using the same pistons, i have no signs of skirt wear. the tolerances were set to cp specs. Now trust me...my car fully warms up before i even move it, let a lone race it, so i dont race it with piston slap. that would probably cause major problems, but i dont want to find out...piston slap in a forged motor is normal..you probably just cant hear it through your cast iron block and by the time you do hear it, your right, it probably is a very bad thing.
[/b]

I just noticed something, it only happens when i first turn the car on *when the engine is cold* and when i step on the gas. It does not happen if i just turn the car on and its in idle.

Is it piston slap still? or something releated maybe the tranny, or something hooked up to one of the belts...

Note: if you rev the engine in idle, dont hear anything wrong, sounds normel.. only when you put the gas on and are moving.

[dubcac]

You're positive it's piston slap and not valve tap?