Broken spark plug in cylinder head of 1989 Convertible (Solved)

[JensenHealey]

I attempted to remove all the plugs from the engine on the white 1989 Convertible and I was successful with seven of them.
However the eighth plug in the right front corner of the engine broke apart as I was trying to remove it.
Here is a photo of the eight plugs lying on my work bench. One of them does not look like the others.

So now I am working on trying to get the broken off part of the spark plug out of the cylinder head.

BTW, I don't know about anyone else here but I ALWAYS put a light coating of never-seize on the threads of all spark plugs I install into engines I am working on. The strange thing here is the threads on these spark plugs are not really that corroded but the outer part of the plugs beyond the threads looks really bad. This car has 50K miles showing on the ODO and I bet it has NEVER had a plug change during those 50K miles.

Edited December 25, 2020 by JensenHealey

[IndyJimW]

I have seen this on small block CNG engines but not on gasoline. Small fat easy-out may work, just don't go too deep or you could break off the electrode. It may come out with the treads. Spray some penetrating oil also.

 

Good luck

Jim Wood

[JensenHealey]

I spent some time over at my shop again today and I have to report that I was successful at removing the piece of broken off spark plug. I used an easy-out and about a week ago I used an acetylene / oxygen torch to heat it up for a few minutes.

[IndyJimW]

Good job! Very unusual for that type of spark plug to break like that.

Good luck,

Jim Wood