I am a home DIY bloke who has never heard a big end going before and am not sure whether it is or not. The noise seems to come from under the tmic somewhere when stood with the bonnet up.
As per the video below, it only happens around 2500 and a slight recurrance a little higher up, it does not make the noise whatsoever when lifting off and letting the revs die back to idle. The car seems to pull just fine.
Mods include sti pinks, vf24 turbo, mapped since feb 2012, running reasonable timing (no knock) and 18psi peak dropping to 15.5 at redline. Any noises on deceleration are pops from the exhaust (3" turbo back). One other thing I noticed was the rubber flywheel cover has fallen forward onto the engine so can see it spinning but doesnt seem to be causing this noise.
Any ideas from the more experienced engine guys?

 

could be wrong but sounds like the early signs of a bottom end knock to me !!

hard to tell from video inside the car as this dampens the noise and masks it

my other halfs car sounded very similar but a lot louder when she first bought it ,its currently on engine stand as we speak awaiting tear down lol

im sure there are vids on youtube of knocking imprezas have a listen as may give you an idea

seems to be around 2.5k the knock as you increase and decrease revs can be heard here


i await a more expert opinion which im sure youll get !!

 

It only happens when holding the revs or increasing them slowly, decreasing noises is the exhaust popping. Think I might have to source myself a spare block. Good time to do timing belt etc too anyway but not an expense I need after xmas.

 

Sorry to say mate but it does sound a bit like the death rattle having been there with previous scoobys, My advice would be to drop the oil and have a good look at it, or even drop the sump and look in there too, Does sound like its in the early stages to me though, My guess would be cylinder 3 nearest the turbo. See if you can do an under bonnet vid, Just pull back on the throttle body when its running to rev it.

 

Took this last night also, maybe a little clearer.

 

I have no mechanical knoledge (as you know) but from other videos i have seen on Youtube , it sounds like what you fear

 

i would start saving now mate after listening to that second vid ....definately sounds like death rattle


like said drop oil and filter and also sump and check for metal particles ,magnets are handy for this

 

Fear is the wrong word
I knew it was bound to come (hence my slightly sympathetic timing map) as the previous owner didnt look after it, I change the oil every couple of thousand miles but if the damage was already done, nothing can help it so onwards and upwards.
Maybe make a little more scope for more power too, nothing mad though.

 

I think Ill dump it this weekend, got a new genuine filter etc here already.

 

This was my old block

A vid of where the knocking came from after i took the sump off



And the sump :shock: