could someone give me some pointers to a light tapping from my sti v3 my97 import on start up from cold i got a little knocking sound from the engine on a light throttle at about 1500 to 2000 revs,when its above that thers no knocking and when its fully hot theres no knocking at all, as it starts to cool down again the knocking returns,it pulls with no hesitation ever,i have read on other sites there was a problem with piston slap in some of these engines,does anyone have some idea if its small end wear in 1 of the pistons and possibly whats involved to cure as winter is here and seems a good time to repair if needed,cheers Paul

 

Welcome. Noises of any sort are notoriously difficult to diagnose accurately over the internet. Nothing beats a trained ear under your bonnet. What you describe is most likely light slap, might be the early onset of bearing damage (unlikely), could be something as subtle as a degraded heatshield or a noisy injector.

If you tell us whereabouts on the planet you are, someone might be able to suggest a suitably local trained ear.

 

hi again and thanks splitpin for your reply,im living in the rhondda in south wales and someone that has lots of experience on these machines would be greatly appreciated

 

You need a pro to listen to it to confirm but it is probably the piston slap problem that afflicted the majority of MY97 cars. You want to hear mine at 5am on a cold morning. Sounds worse than a bag of spanners till warmed up LOL

 

hi his n hers thanks for the reply i would imagine it could be either piston slap or perhaps 1 of the small ends a bit too much clearance i tried it again today it rattles for a few minutes but when really hot theres no knocking which i think is good cause it gives me an excuse to get it very hot so it dont knock lol

 

i have a v3 sti with piston slap also mate , 1 thing is though dont rev or move the car until its FULLY warmed up , may take a while but if u just take of and rev it to heat it up intentionaly then u r certainly askin for trouble mate , mines is also perfect when warmed up and more frequent oil changes wouldnt go amiss either

 

97/98 cars had a reputation for slap and were a warranty fix when new.
I found mine slapped much more colder weather - but once warmed up then the noise would go.

 

mines is slappin like a bitch lol and HAS got worse depending on weather , the v3 and v4 pistons have a very high copper content which i believe is part of the problem as to the rate of expansion , cold weather would prob affect them quite a bit more i suppose its like 0* outside 1* if im lucky in the morning , didnt do this half as bad when the weathers hotter as i only noticed it when the winter came , that castrol oil on the telly keeps stikin in my mind about startup protection LOL but i think ill stick with millers , going to see next friday if puting millers in it will help any but i prob doubt it ???

 

it scares u a little as i mistook , and others probably , the same noise for knock a year ago lol

 

if it goes when warm then its probably pistonslap.
i have a 93 wrx with piston slap. its absolutly nothnig to worry about. just keep an eye on the oil level. in the summer mine is gone.

 

i get it with my 02 sti and it can be a worry, im gonna get it checked out just to be sure.

 

Yeah it's notable on the STi 'forged' pistons as they are designed to expand to the correct tolerence when up to normal temp. This means that when cold, they are ever so slightly undersized and 'slap' against the cylinder walls a bit. Even more noticable in this weather!

I have STi v.3/4 pistons in my Zen-build and really noticed the slap until warm (when comapred to the origianal WRX 'non-forged' pistons). Got used to it now though, and don't really 'tune into' it anymore... Mind, my exhaust is probably to blame for that lol.

 

I have only had this scoob a few weeks and i noticed the noise last week, i had fresh oil put in over the weekend but as the engine was warm the noise was absent so will just have to see how it goes lol

 

As said, we all think it's normal for STi 3>on... Don't worry.

 

mines sounds like woody the woodpecker lol