I wonder if JB-Weld would fix it.

Brent <NONE@NOSPAM.COM> wrote in article
<10n6g4e62j7pf53@corp.supernews.com>...

You don't really need to repair this.  All you need to do is coat the
threads of
the new exhaust stud with a liberal amount of high-temp RTV silicon.  The
stud
will block the hole.

Ted

As long as the stud thread doesn't leak it isn't an issue. Loctiting the stud
in is probably as good a way as any to ensure this. Silicone sealant is
another. Maybe even both. There should be a good 1/4" below the bottom the stud
and the start of the water jacket. Squirt a suitably sized i.e. small dollop of
silicone into the hole and wind the stud in which will push the silicone down
into a plug at the bottom. Let this set for 24 hours, take the stud back out,
clean it up and loctite it back in. Don't use so much silicone it pushes into
the water jacket and blocks that too.

You could also do the same with araldite or JB Weld instead of silicone.

If the whole is visible from the water jacket side (I know probably not) I'd
attempt to get a weld shop to try and seal it before you install it. You may
also have them fill the whole and have the stud location then drilled and
tapped. If it's worth fixing I'd probably get it welded.
Aluminum is easy to weld, you just need to know how.

Brian

Brent, If the head is off the car you could weld the hole shut. However
if it is still installed the easiest way to repair it would be to tap
new threads all the way through the hole using a bottoming tap. Leave a
SMALL area that isn't threaded at the very bottom. Make up a plug for
the hole by cutting a short piece off of a bolt of the correct size. Cut
it off grind it nice and clean. Cut a screwdriver slot on one side that
is just deep enough so you can turn it. Now coat the threads with a
coating of Loctite and screw it into place. Let it set a bit and then
measure the bolt that is going into that hole so that your sure it
doesn't bottom out. When you reinstall that bolt give it a light coat of
sealant.

Easy and quick.
Oh and next time Measure another bolt and mark the drill !!!!!

Are you sure the stud hole was "blind" in the first place? Exhaust studs
typically DO penetrate to the water jacket on many engines. Maybe you
just drilled all the way through the stud.

Re-thread or helicoil the hole (using hi-temp silicone or loctite on the
outside of the helicoil) and then immediately install the stud and coat
it with high-temp silicone as well.