Bent Valve/push rod?

[I Leak Oil]

Ha I hear ya. You know what boat stands for right???? This applies to rovers also.
"B"reak
"O"ut
"A"ntother
"T"housand

[JimCT]

Old gas

Old gas can end up forming a varnish that acts to glue the valves into the valve guides. I have seen guides pushed out of the head because of that.