Hi Ashley,
Thanks for the interest. The cracks you have observed are only superficial, for some strange reason there is an undercut just underneath the dome surface. This undercut increases the diameter of the spark plug hole by approximately a sixteenth of an inch. Maybe at some point the plug threads have been “helicoiled “and the tapping drill was stopped short of going all the way. The plugs have not been removed during the repairs so far, to maintain the integrity of the threads, also in the pressure tests carried out so far, there have been no leaks. John
|