Triumph Repair: Spark Plug Sheared off in Engine Head., acetylene torch, triumph spitfire 1500

Question
Howard,

We meet again.

The vehicle is a 1974 Triumph Spitfire, 1500.  It is in the final stages of a complete rebuild.  Although, the first part of the rebuild occurred about 7 years ago, the vehicle has been housed in the garage since that time.

Today, when pulling the spark plugs, one of the plugs sheared off, even with the head.  There is no hex end remaining.  The ceramic portion remained with the hex portion.  Therefore, only the threads, flush with the head remain in the block. Nothing, to my knowledge, fell into the cylinder.

An extreme amount of steady force was being brought to bear in an attempt to turn that plug.  Seven years of sitting in the garage, most likely, corroded it.

I looked at an easy-out today.  However, the small size of that tool, when compared to the force and tools to originally turn that plug leads me to believe that won't work.

Is there anything, short of pulling the head, I can do to remove the remains of that plug?

Thanks,
George

Answer
Hi George,
Over the years I have had to remove the threaded portion of a broken off plug with the head on and off and it really depends on how badly it is seized in the head. I got most out by heating the left over piece of plug with a acetylene torch, then inserting a large "EZ" out that has been left in a freezer. The heat tends to break the rust loose but expands the plug, the cold EZ out tends to cool and contract the piece of plug while the head is still warm. I have however had to drill out some and a few that required an insert as the threads were damaged in the process. I don't know of any way to tell you that will always work in all cases and I don't believe there is one other than to remove the head and jig the head up in an end mill and cut it out which is costly and time consuming.
Howard