JimH,

If the timing chain breaks or jumps only one tooth, one of the pistons will push against a valve and stop the engine from rotating. If enough force is applied, such as cranking the engine with the starter, the piston will cause the cam towers to break, and possibly bend a valve. If this happens when engine is running, more may be damaged.

Possibly after a while, the hydraulic valve lifter may leak down and then the engine will turn again.

P E H