Hi,

My mates just bought a nice S1 Escort RS Turbo

Running 254bhp.

He had it on the track at Croft last sunday with no problems,

We then went for a drive down the M1 racing a scooby on the way (blowing it away).

A really loud knocking sound started coming from the head which went away and came back depending on how high it was revving.

Still ran ok, didnt overheat or anything, managed to get it home.

Anybody any ideas what this would be????

Cheers.