Ok I have found out what is happening. The crank is moving forward when the clutch pedal is depressed very slightly. This moves the timing chain away from the timing cover. I remove the slight pressure on the pedal and the crank moves toward the rear of the engine causing the timing chain to hit the inside of the timing case. Am I correct in thinking there is excessive play in the main bearings . Is there an easy fix for this. Maybe space the alternator to-wards the front of the engine causing the belt to pull the crank forward. It wouldn't need to be much. Any thoughts