Burnt valve questions......
How tight does a valve need to be in order for it to burn?
I believe the valve burns because of inadequate heat transfer from the valve to the valve seat due to it being held open. Is this correct?
Are larger valves (ie two valve per cylinder versus four) more prone to burn at an insufficent clearance versus smaller valves?
Is it usually an exhaust valve that burns?
Any experiences or thoughts are appreciated.