There's a locking pin to be inserted into the block to lock the crank on TDC adjacent to the vacuum pump, then there are two marks on the camshaft & inj pump pulleys that should align with marks on the head, then you need to fit a special locking plate between the two pulleys.
If the belt has snapped there is a great possibility that the valves and pistons have become very intimate with each other as this engine is know as an interferance fit and damage is most likely!!!
nigel, March 2011
