Broken manifold stud in head

I did almost the same thing (broke a tap in a cast iron head) and was about to start looking up shops who can EDM when I had a brainstorm.

I was able to use a very high quality (read: really hard) pointed punch to shatter the tap. USE GOOGLES! From there I was able to remove the pieces with a dental pick and drill around the larger pieces with a very small bit and remove them with a pick too.

This method is a major ***** and took me probably 2 hours. I had nothing to loose at this point, but I would not recommend it to everybody. You need to wack the tap at just the right angle to not drive it deeper, yet just where it looks it might chip or splinter. It's like freakin' cutting diamonds.

A good practical "feel" for different kinds of metal and how they act/react under stress is necessary to to pull this off.

I'm really liking the filling a nut over the stud/extractor idea. I've never tried it and I hope to never have too, but this is good info to file away in my non-alcohol absorbing side of my brain.

If this is an exhaust manifold stud, don't bring it to a shop that will just drill it out the threads and all then helicoil or you will have a coolant leak. Heli-coils work great for fastening but are not oil/water tight unless they locktight red them in and you use high-temp silicone on the stud. Liquid teflon won't even seal.

OK, I'm worn out now. Time for another brew.:drinkers: