Anyone know of a video of our cars running with piston slap? thanks.
Piston Slap
- Thread starter elyrain
- Start date
picture your car with a powerstroke in it, and you've got it.
hahahaha, true..
Yeah, it was cold yesterday, 50 deg or so, cold for cali anyways.It was making all kinds of noise till it warmed up. I'm pretty sure that's what is was.
Just idling or driving at 3K RPM?
not to much at idle, I could hear it more when driving 1-3k.
no I've had one of those before, this was something else.
01cobravortech
Banned
I don't remember my 01 being loud at start up or while driving. It did have a loud slap though when I had spun rod bearing though.
Oh oh..
Rod bearing???
+1
who built your motor, and what are the p/w clearances. should say on your build sheet.
as for your problem, what kinda pistons were used?
My JE pistons made a good bit of noise when cold. My CPs however, are nearly dead silent. Sounds like a stock motor.
The stock motor almost all make noise when its cold out at under 3000 rpm. not idle. But if it never used to do it when it was cold and just started i might be worried!
these are the cheap probe pistons, I don't know if it matters but the rings are gapped for nitrous, .020 on top I think. It was built by a good shop.
A rod knock does not go away when warm, this goes away completely. I think I may have a header leak...
A rod knock does not go away when warm, this goes away completely. I think I may have a header leak...
ring gap doesn't matter, piston to wall clearance does. I don't care how good the shop was, if they don't give you a build sheet, they blow.
Piston slap isn't the end of the world, but you need to know why its occurring. If its because the p/w is a bit bigger for nitrous, ok, but if its because you have collapsed skirts, then its a problem.
Im assuming these "cheap" probe pistons are 4032 alloy? If so, then the motor should be dead silent. They don't expand as much as 2618.
Piston slap isn't the end of the world, but you need to know why its occurring. If its because the p/w is a bit bigger for nitrous, ok, but if its because you have collapsed skirts, then its a problem.
Im assuming these "cheap" probe pistons are 4032 alloy? If so, then the motor should be dead silent. They don't expand as much as 2618.
FWIW I've had piston slap on my stock '01 Cobra for about 4 years. Sounds like a soft rattle between 2,000 and 3,000 rpm when cold...disappears at full operating temperature (5 to 10 minutes). Ford's says it's normal on some stock Cobra's (TSB about it)...not that I believe them. If it was a rod bearing it would have gone years ago. If your sound is similar and disappears when warm my guess is piston slap. Don't forged pistons slap in some aluminum motors? (I know stock '01 pistons aren't forged, but maybe yours are.)
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yes, forged pistons typically slap more. But his are 4032, which expand less than the more common 2618. Plus, some better pistons are pretty damn quiet (CP and diamond)
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