In my case,I believe the oil starts to boil and burn giving off gases and smoke, building pressure under the #3 gasket.enough to force the high tension wire to pop out.the oil is boiling enough to coat the open hood. I have not started working on mechanical issues,so this is just what i have observed.not sayin' it's your issue.But cre is absolutely right,as usual
check to see if it's going to be worth your effort.