Hi there i have a version 4 sti type r and have discovered a knocking noise from within the engine bay at around 1600-1700rpm?? Been told by a local import company who do tuning as well that if there was something like a big end gone that i would no about it and would hear it clearly.....he said maybe a heat sheild.......The noise also sounds as if it is in time with the engine's rpm and can be heard slightly above and below 1600-1700rpm but not as much.....a little concerned...any help much appreciated...


Joe.....

 

piston slap? right kind of era i think - kind of a bok bok bok sorta noise? Think there is a sound file around here somewhere.

Does it go away when warmed up?

Ritchie.

 

Sounds similar to what I have at the same revs. Had it since the de-cat was put on, but I have no heat shields anywhere now so cant be that. Was on the rolling road at the weekend up to the rev limiter twice and no ill effects, so it cant be that serious

 

Is it just at 1600 - 1700rpm if it is then i would'nt of though it
was slap, as this can normally be heard quite clearly at tick over.

If it's at higher revs then it sways more towards lower end problems.

Rob

 

I have personally experienced piston slap and although when it develops it is audible at idle i certainly found it more pronounced with a tickle of the throttle. Mine then quietened down after about 2000 rpm.

I'm sure they all behave in slightly different ways but it is worth a quick investigation - particularly the model age of your motor. If nothing else to rule it out. Good luck, hope its a loose heat shield.

Ritchie

 

Another possibility is the cam belt tensioner although at those revs the action would have smoothed out somewhat.
JohnD

 

Well went to Barrets Motorsport yesterday to get the oil changed and it turned out there was 6litres!!! of oil in it which is way to much so we sorted that problem...but it had no effect on the tapping/knocking noise at 1600-1700rpm....these guys used to run a group n rally car and they seem to think that it could be a tappet that is worse than usual.....but in my opinion its not that click click click noise of a noisy tappet...and am swaying towards the idea of piston slap....the performance is not affected one bit and there is no smoke as i followed the car on full chat yesterday........am i being paranoid or should i just fix it when it blows if it does????

Joe.....