The Mechanics Worst Nightmare!

[jlandry@domain.elided (John A. Landry)]

OK Gang, I could use some suggestions...

This past weekend while tearing down the V392E I purchased from a local
wrecking yard, I managed to snap off one of the water pump housing mounting
bolts about 1/16" from the front face of the block.  The bolt is 3/8"
course thread and is in a blind hole.

I center punched the remains of the bolt, drilled it completely through.  I
felt I did a pretty good job of getting the hole centered and straight, so
everything was going good so far.  I then drove in a Rigid brand broken
bolt extractor which measures 1/4" OD.  This type of extractor has splines
which run lengthwise to engage the inside of the drilled hole.  A special
nut then slips over the outside of the extractor protruding from the broken
bolt, where it is turned to hopefully remove the broken bolt.

I tried working the broken bolt back and forth with no luck.  I tried a
little more force and *snap*... the extractor broke about 1/8" from the end
of the broken bolt.  It broke in such a way that I cannot get a vice-grip
on it to attempt to pull it out.  So now I have this super hardened
extractor in the middle of a super stuck broken bolt.  I've had this happen
before and always lucked out and somehow managed to get the extractor out.
This time it looks pretty hopeless.

In retrospect, I know I should have tried to weld a nut onto the end of the
broken bolt, but that's hindsight.  What I'm looking for is suggestions on
how to deal with the situation I'm in.

I've had a couple of people suggest I try super heating the broken
extractor with an acetylene torch to anneal it, making it possible to drill
it out.  This might work but sound difficult.  The heat would have to be
incredible to get the extractor that hot (when tightly surrounded by a
heavy engine block).  Then I'd probably need a tungsten carbine drill, and
doing this with a hand drill, I would have great fun trying to keep the bit
on the extractor instead of walking off into the softer surrounding metal.

I've also been told I can't expect to weld something to the extractor in
order to try and pull it out with a slide hammer, so that's out.

I was also warned against trying to weld a nut to the end of the broken
bolt with the extractor still sticking out.

So here's and idea I thought of this morning...

I do have access to the opposite side of the block wall behind the bolt
hole.  I was thinking I could drill a small hole through the backside of
the block wall (say 1/8" ID) into the bottom of the blind hole, so I could
insert a punch and drive out the broken extractor.  The backside of the
block wall is right under the valley pan, and I don't see what harm having
a small hole there once the water pump housing mounting bolt is there.  I'd
probably fill the small hole with JB Weld or something anyway.

So if that idea worked, once I get the extractor out, then what do I try?
I mean this bolt is not going to move?  I'm afraid that trying to weld on a
nut to what remains of the broken bolt will be fruitless.  As I mentioned
in the beginning, the broken bolt was only sticking out 1/16" and now I've
been drilling on it.  All that remains is a thin wall of the bolt.

If I get the extractor out, I suppose I could let a machine shop mount the
block in a mill/drilling machine and drill out the hole exactly on the
enter and insert a new Helicoil.  I can't do this at home because I can't
insure the new hole I'm drilling is properly centered on the original hole.

Any suggestions on how to deal with this problem would be most appreciated.

Regards,

John L.
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