scooby.steve555

iTrader: (5)

hiya guys

I have a 98 version 4 WRX import, running 300bhp with panel filter decat and fuel pump if that info is going to help with this.

Basically when i start up from cold the car runs fine on idle but as soon as you get to about 1200 rpm it starts to make a really harsh tapping or rattle, does not sound healthy at all.
Now the strange thing is it goes away once left for around 15 minutes to warm right up which i can't get my head around as normally when the oil is thin a knock etc will get worse.
My guess is something must be struggling to get oil to it when its thick but I'm not sure what..

Wondered if anyone could maybe shed some light on what it might be that's tapping and how serious it could be?

Any help will be useful

Thanks, Steve

ALi-B

iTrader: (1)

Have a look on youtube for bigend/rod knock on imprezas.

Here a good example of one ready to let go, (well, a bearing has gone, but as a result, the rest of the engine's not got long left to live)...


Does it sound like this:



If so, get your wallet out, its going to be expensive

carpeys

hi i have the same tapping on my v3 sti,been told its piston slap from what i believe to be a forged engine,had mine for past 5 years been thinking of getting it sorted but when hot has no tapping and still goes like stink so prob save up and do a stroker conversion to it

The Pink Ninja

iTrader: (23)

Forged engines genrally have noisier pistons anyway but if it's a standard engine and doesn't sound like the above do a search for piston slap as it was common on a few of the earlier engines, Not sure which years though.

scooby.steve555

iTrader: (5)

This is definitely not piston slap unfortunately.

It's a lot sharper noise, like tappets really..

And as i say it goes away once its hot, surely a big end would get worse as the oil gets thinner?

Dmacnz

Prob just noisy tappets....Maybe some special oil additive can help you out.