I recently had an engine loose power at the end of a race. After the loss of power, the engine still ran, had good oil pressure, but sounded like a lawn mower. I began to tear down the motor yesterday and found that one of the exhaust valves on the #4 cylinder had come in contact with the piston and was bent. I do not see any other damage in the cylinder.
This motor as many (too many) races on it. What has to fail in order for the valve to hit the piston? Timing belt looks fine and as I mentioned above engine would run after the incident. Also should I expect to find any other damage in the motor due to the piston and valve colliding?
Any insight is appreciated