After getting my bottom end rebuilt, (crank, conrods, and clutch all sti parts) and a new oil pump and big end shells, my wrx wagon (my-96) was fine for about 500 miles easy running.
After giving it a bit of stick at weekend it developed a nasty rotational knocking noise.
It is not audible when building up rpm off boost, engine is not noisy (except for my slightly leaking header flexi pipe) but as soon as it comes on boost the noise is there, lift off slightly and it goes away when boost drops off.
It is still boosting ok and does not seem to be loosing much power.
Any ideas people?

 

check here:
http://bbs.scoobynet.co.uk/showthrea...67#post3405267

 

i had something very similar to my 95wrx, was a grinding noise, where stationary but when acceleration i couldnt hear it as much, ut then got to a point when it was really loud stationary, ended up to be the water pump bearings just about to die, thankfully it didnt seize up otherwise big bucks, now fitted and sorted,

could be the same too, just a long shot!