I think you have convinced me to pull the head. There is at least an 80%
chance the threads are already buggered (that makes up for "detritus").
Also, pulling the head will give me a chance to check on the condition fo
the cylinders.
Marcus A. Pryor
For a new age of reason
> Bite the bullet and pull the head;
> Given the outer steel shell broke at the weakest point, the minor
> diameter of the the threads, the likelihood you will have to repair the
> threads is probable. You don't want pieces of steel from the old plug
> threads sitting on top of the piston and creating hot spots or worse
> like jamming a valve.. If you could manage to remove the remaining part
> whole without drilling, you could re-tap the aluminum head and insert it
> with a better chance of survival but still iffy. I just had the same
> happen to my Miata and the cost by a competent mechanic with misc. was
> 900.00
>
> Marcus Pryor wrote:
>
>> I have a peculiar problem, and I would like some opinions from those
>> who have walked the walk. The reason my '68 2000 doesn't run is
>> because it has a broken spark plug. Here's the rub; it isn't broken at
>> the usual place (at the base of the insulater) but, believe it or not,
>> the iron base of the plug sheared off just above the threads!
>>
>> I have studied the problem with an eye toward removing it without
>> pulling the head. I would like to see if I can get it running the way
>> it is. I figure if I drill it out (best solution), I will get some
>> detritus into the combustion chamber. Any thoughts before I tear her
>> down?
>>
>> Marcus A. Pryor
>> For a new age of reason
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