The most crap ever stuck in an exhaust stud?
 

Some of you may recall the 6 hours and 8 bits I went through last summer removing my timing chain guide rail bolt. Well I've gone and done it again only this time it's bad, real bad.

I've got the entire powertrain out of my '87 300SDL and I've got the head off, sitting on my bench.

When I was taking the exhaust manifold off two exhaust studs sheared below the surface.

One of them came out with little issue. I decided to replace the other studs and they all came out nice and clean.

However, the stud that is closest to the firewall is where the fun started.

I started drilling my pilot hole in the center, everything was going good. Then I think I may have moved the drill on a slight angle and *tink* my bit snapped off flush with the stud.

The bit wasn't really jammed in though, I could wiggle it around.

So I decided that I needed some room on either side of the bit so that I could get needle nose pliers in there and pull it out.

I got a smaller bit and started to carefully drill on either side of the drill bit.

Things were going very well and I was making progress. I just needed to drill a little further and then *tink* the 2nd bit broke off in the stud.

At this point I'm thinking I'm totally screwed but being the optimistic person that I am I looked a little closer and realized that the bit was still loose in the stud and I could probably pull it out.

So I got another small bit and started drilling next to the stud again. Wanna take a guess where this is going? *tink* Three super hardened drill bits broke off in the stud. I turned off the lights and left the garage.:behead:

It's been sitting for a week now while I think what I can do.

All the heat and PB in the world won't do me any good because I can't get a hold of the stud.

To top it all off, I used such hard drill bits that nothing I've tried will cut through them.

I even wore down a diamond tipped Dremel bit trying to grind through the drill bits.

At this point I'm considering dynomite or a new head.

Anyone got any other ideas?

Weld an extension?

Many machine shops have a device that disintegrates broken studs without damaging the host item.

Sixto
93 300SD 3.0

You need to get this EDM'ed out (electrical discharge machining), if possible.

At least the head is off!!!

Yes, call around to machine shops the EMD machine is awesome to watch. You chuck the head up into the machine, they lower a drill press like device onto the stud, push a button, and the machine humms and the stud, drill bits everything just pops right out.
my local guy only charged me 30.00 to fix my brother's similar problem in a dodge 440 head.
John

How long does it take?

Sixto
93 300SD 3.0

only takes a few seconds. it's really awesome to watch.
John

Alright I guess it's time to take it to the shop.

I was hoping to fight this one to the death but I suppose given the circumstances, it's probably time to throw in the towel before I make it even worse.

I didn't realize that having it EDM'd could be as cheap as $30. I'll spend that much on beer while I'm trying to get this stud out.

As always, thanks for the help!