Re: Totaly stumped now!
right, checked all the plugs no problems there, compression is in the 190psi region accross all 4 at cold, have put the stethoscope on it but cannot pinpoint the bang to one cylinder as it resinates around the whole block! have run it with the cam cover off and it makes no difference to the noise.
the noise is constant when driving and ticking over, loaded and unloaded, up and down the rev range which indicates its a mechanical (metal on metal) problem but its not audable while cranking over.... which indicates its combustion related?
dont want to take it to a garage because they'll just say "needs a full rebuild"or "replacement engine" which i just cannot afford and it would be the second engine its had! i've only managed to drive 40 miles in it 6 months so my patents is starting to wear a little thin having thrown alot of money at it, i mean i knew it was an alfa when i bought it, i've owned italian stuff before but never had anything like the problems i'm getting. its run on the most expensive oil, have'nt had a chance to rev it hard yet.
thankyou for the suggestions though.