I have a Heli-coil tap broken off in my head (yes, it feels like it too!)
A tap extractor won't budge it and the super hard drill bit I bought doesn't hardly scratch it either. I really don't want to remove the head and take it to a machine shop. I haven't even fired up this new engine yet. I'm just about ready to drill four small holes around the flutes of the tap, effectively hogging out the original hole, to try to get this thing out. Then I was thinking of a sleazy JB weld fix to put the heli-coil back in. The hole in question is for mounting the exhaust manifold to the head (Oops, now you know it's not a Slant 6, it's a 318) Does anyone have any other suggestions before I do something stupid? I've gone through half a can of penetrating spray, and bent the tines on two tap extractors. Would a propane torch to heat up the head around the tap help or hurt the situation? Thanks,
Rob

I had same thing happen on a tractor one time. I used a propane torch on area around hole to help that expand and used a set of crappy old needle nose pliers that I drove in just snug with with a hammer, then worked that out, don't give up on it just yet, it took me awhile but persistence paid off. -Spin

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Project B-52 Crew

They are brittle enough that you can usually shatter them with something like a nail set, or small center punch, and a few judcious taps with a hammer. It works better on smaller sizes, so you might have difficulty with one that big.

I agree on tapping (wacking) to try to break it up. hit on it sideways to start, somtimes that helps loosen the thing's grip.

Remember, that head stud hole is a thru hole into the water, you can drill small holes around the broken bit and then drive it thru.
DD

Thanks everyone. I didn't think the hole went through into the water jacket. I think my problem was that I bottomed the tap in the hole I drilled and gave it just a little too much twist. It broke off below the head surface. I'll try chipping away at it a little first with small punches to see if I can break enough pieces off to loosen it up. I will also try the heat, penetrating oil sequence a few times. Any suggestions on a good place to get a small propane torch? My last resort is drilling more holes. I'll let you know how it goes. Thanks again everyone!
Rob

we used to use tap extractors. They had fingers which reached down the spaces between the flutes. They came in different sizes and different #'s of flutes. They worked most of the time. If it was particularly tough, we sent them to a shop which filled the hole with a solution, and then applied some kind of electrical current to them. They just disolved, without damaging the part!

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'66 Cuda 225/4spd
'66 Dart GT convertible 225/auto
'64 Dart GT 340/4spd

The solution and elctrical current sounds interesting. I tried hitting the tap with different punches, but that didn't seem to do anything. I'll try to find a propane torch. I also need to get some more tines for the tap extractor. When I have success I'll let you all know. Thanks,
Rob

heat it cherry red w oxy torch & hit it with a blast of ox. mine popped right out.