i've done three different engine type octy timing belts for mates all petrol. i was wondering, for when an oil burning mate comes knocking with a t-belt under his oxter, do you have to use the locking tool for the camshaft as instructed by the manual or can you carefully use timing marks.i have'nt got a locking tool.

I did mine without a locking tool :-)

According to a guide I've got, you can lock the injection pump with a 5.5mm drill bit. It doesn't mention any other locknuts, but does recommend painting timing marks on the injection pump and cam pulleys, belt and rear cover, then transferring the marks to the new belt.

You don't necessarily need to lock the pulleys. So long as you don't undo any of them you can only be a whole tooth, or multiples thereof away from correct alignment. So do as Ken says and mark the pulleys and the belt before you remove them. That way you can't go wrong.......