hi all; not sure if ive posted in the right place, but hey ho

i bought a 2wd sapphire cosworth on a G plate about 3 months ago, i'm new to cosworths so my knowledge isnt great

The engine has done 60k and its never been rebuilt, its running stage 3. (350bhp ish)

now when i start the engine up from cold it sounds really rough, now is this piston slap? once i've driven the car for 10 mins - 15 mins the noise has virtually gone

the car also uses a bit of oil, is that common with cossies? or is this a sympton of something else?

if it is just piston slap, should i be overly worried? i havent got the money at the moment to get the bottom end rebuilt

any help appreciated

Cheers, Terry (a worried owner!)