<VV> Oops - need advice

[Chris & Bill Strickland]

>It sheared the plug off flat against the head - so just the metal of the sparkplug is in the threads of the head with nothing to grip. ... a mouse had made its nest around this plug, so i suspect that getting the remainder out will be a challenge.
>

Since it does sound like you broke the hex head off of the spark plug's 
'shell', I will fully agree that this sounds like a challenge.  If you 
tore the hex from the rest of the shell, it is unlikely that any reverse 
twist drill or 'no such thing as an easy'-out will do much good without 
some other more drastic measures, like a cutting torch to split the 
shell.  (And while you were at it, the rest of the shell, too.  But then 
you have debris that won't just "burn up" - yuck.)

I would suspect the ceramic tip to no longer be in the shell, correct?  
Just a hole into the combustion chamber? If so, perhaps you could thread 
the inside of the shell to accept some small diameter motorcycle plug 
for that one hole -- yeah, I hear the purists hollering already -- I 
think the pulling the head route will be the way to go for you..

[Maybe, for a way out idea, you could thread the inside of the shell and 
using Locktite green sleeve goo, lock a good bolt in there to twist on, 
then, when you break the bolt off, you take the head to a machine shop 
for a good laugh!]

I thought the hacksaw idea sounded good, but you will find yourself 
getting really tired of that process in a big hurry, and the threads 
that didn't turn when you had a hardened steel hex to turn them will 
still be corrosion welded to the head.

Running the engine to heat the head sounds good, but  if the tip of the 
plug is in the combustion chamber, maybe not.

Again, under the 'if you have to ask' rule, yes, you probably need help 
-- or just replace the head and save the old one for a conversation 
piece at club meetings and swap meets.

Godspeed!

Bill Strickland