Vauxhall 2.0 Sohc

[swordfish210 20]

Hi, my next door neighbour wants me to do a headgasket change on his Vauxhall Frontera and do a cam belt change while i'm at it. I had a look at it today and it doesnt look too bad, fairly good access to most things. I couldn't however see any timing marks on the cam pulley so does anyone know how to time these engines up and has anyone ever done this job before, anything to watch out for while i'm at it? Thanks. Mark