Broken 1/2" Tap in a cylinder head bolt hole. Major Help Needed

franklin2

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He used a carbide bit. They will drill through taps, ez-outs, and hardened allen wrenches, been there, done that. But they are expensive and chip easy.

And like I said, if he broke a ez-out off trying to get it out, I do not think the 3 or 4 little spindly legs of a extractor are going to get it out.

Besides the extraction welding rod idea, the only other idea is get a hole started as close to the center as you can get it, and if you have larger sizes of carbide bits, slowly open the hole up, till you have cut most of the tap out, and are left with little bits and pieces that can be picked out of the threads of the block.
 

boosted power

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I wouldn't recommend buying a tap extractor, they almost never work.

Russ probably has the best idea of using a copper pipe to protect the threads and attempting to weld it.

Of course if you had success drilling it, you should probably continue to drill it out until you can just pick out the fragments.

As a last resort you could always heat that sucker up with your oxy/acetylene torch and blow it out. I have done this with a 3/4in tap in a blind hole and it did not distort the threads, but I didn't feel good about trying it.
 

Knuckledragger

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If the engine is out of the vehicle and disassembled and you have tried a tap extractor (my experience with them is 50 - 50), call a tap extraction service. They disintegrate the tap with an electrode and the hole is nice and clean afterward. It is less effort and time than monkeying with home made rigs, or drilling the f**k out of your block. And it is not expensive. But finding one may be a trick since they mostly rely on large manufacturing for business, and the economy has put some out of business.

Okay, since everyone here wants to DIY, Get an extractor and give it a try. Use kroil or PB blaster or liquid wrench or whatever you prefer. Use lots of air to blow out any dirt or chips, and take your time. Sometimes you have to wiggle the extractor handle a hundred times before the tap pops loose. Just give it some easy pressure, don't try to show anyone how strong you are. That is the fastest way to ruin the extractor. Sometimes it pays to turn the tap in a little bit more before trying to remove it. That will clear chips that have not broken, or give you a little room to get some lubrication on the tap.

It is not the end of the engine, just the end of your spare time. Good luck!
 

franklin2

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If you get the special welding rod made for extraction, you do not need the copper. It will not stick to the block, it creates a slag that protects the I.D. of whatever you are welding.
 

boosted power

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Never seen that before. Does the slag actually stop it from fusing to the threads in the block, or just protect it from splatter?
 

Michael Fowler

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If the engine is out of the vehicle and disassembled and you have tried a tap extractor (my experience with them is 50 - 50), call a tap extraction service. They disintegrate the tap with an electrode and the hole is nice and clean afterward. It is less effort and time than monkeying with home made rigs, or drilling the f**k out of your block. And it is not expensive. But finding one may be a trick since they mostly rely on large manufacturing for business, and the economy has put some out of business.


It is not the end of the engine, just the end of your spare time. Good luck!

The Tap Disintegrator works! About 30 years ago I owned a Peugeot. Anyone who owned a Peugeot and did their own repairs acquired a reputation and a following of non-gifted Peugeot owners. Diesel Peugeots had a propensity to blow their head gaskets--cast iron block, steel wet liners, and aluminum head. I got to repair many of them. I broke off a tap not once, but twice about a year apart. I found a more-or-less local machine shop that had a magnetic mount tap Disintegrator. It worked like Knucklegragger described. They told me I was their only customer for it in the year between my mishaps.
 

Jbevs

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Glad you got it out. I hadn't checkout your new thread yet. Sorry about all your troubles. I hope you get it all squared away.
 

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