cam timing marks 1.7 corsa isuzu diesel?

Hi all,
I replaced the head gasket of my corsa c 1.7, but now Im having problems with timing. I've locked fuel pump in place with a bolt, the crankshaft is on its mark with 1 and 4th cylinder at TDC. The camshaft pulley is locked with a bolt to prevent moving. In my opinion I've done everything correct but when I put the cam belt on and try to turn the crankshaft it goes only half turn and stops. What could be the reason for that? Is it possible to have put the camshaft wrong?

Bsr
August 2011

camshaft timing is done using an m6 bolt through the hole in the sprocket, lines up at the 9oclock area, the hole it goes into will probably be full of gasket sealant, the diesel pump uses an m8 bolt in the 4oclock area (if i remember), the crankpulley has a marker pin at 3oclock line this up with the cut in the bottom pulley

j bremner
April 2008