Had a funny noise on my expert e7 taxi sounded like some of the videos I've seen for bottom pulley. Bottom pulley is fine and the engine had reduced power now won't even turn over. Thinking maybe the timing belt had jumped or let off tension i regimes using the marks from when I replaced timing belt 18,000 miles ago aswell as the locking pins for crank and cam. All retimmed it won't turn over as if it's locking? Any ideas gonna take the rocker box cover off and see next but thought I'd post on here to see if anybody had any ideas?