Car ran hot a few times kept adding water until oneday loose of power and spurtering.took heads to be shaved,had to tap a couple holes,and theard,one rocker arm stud hole did not go deep anough so took washers grided down sides to fit in rocker to tighting did not torque just tighting rocker until it would not move.it seems like timeing is off,could it be from driving a few miles before i took heads off,running hot?please help