just got my 383 checked by my mechanic because i thought i was hearing an exhaust leak. he said there was no exhaust leak and that the noise i was hearing was wrist pin/piston slap and was normal for high performance engines.

is this correct?

thanks!

 

piston slap is normal for forged engines. especially when piston to wall clearances are .005" or more. it should only do that on cold start though. it should not make any noise when warm. i'm not framiliar with wrist pin slap. i don't see why it would slap on anything, since they are pressed or held in by retaining clips.

 

thanks for the reply! i think i did not state the part he said about the wrist pin correctly. i think he said the noise could be from piston slap or the wrist pin moving around a bit (a little bit of play). you are right...nothing for the wrist pin to "slap" against.

in any event, i am relieved to hear someone else say that the noise is normal...and it IS only when it's cold as you mentioned. once it gets good and warm, you can barely hear the noise anymore.

thanks again!

robert

 

yeah. forged aluminum expands more than cast aluminum because of its properties and materials used. all manufacturers expansion rate are different. My je's were .005" piston to wall clearance, and my new speed pro forged are .0015-.0020". they slap because of the greater clearance on cold start. they expand to normal clearances when warm.

 

so is it safe to say that no harm whatsoever is being done when the slapping occurs while it is cold?

 

yep.. let it warm up before romping on it.. and yo ushould be good.. start noticing it getting louder as rpm's increase after it warmed up.. and you might have a problem