holmes677

I recently pulled the 305 engine from my camaro. while pulling the engine, we put a bolt in opposite ends diagonal from each other at the two farthest bolts holes in the heads and strung a chain between the two. As you can imagine, something had to go wrong. One of the bolts snapped off flush with the top of the head. I dilled down into it and ran a tap down in it, trying to be able to turn the bolt out, the tap broke and now i cant drill it out anymore b/c the tap is too hard a metal. I NEED HELP! Any idea would be greatly appreciated. I figured i could take it to a machine shop, but i dont want to spend the money if i could do it myself.

angel71rs

As you have no doubt figured out, a tap is not good for backing out a busted bolt; you need to use an easy out, which has reverse flutes.

As for your current dilemma, you are right, taps are made from very hard tool steel, so you will not be able to drill it. I've done it on a mill with a carbide drill bit, but it was tough.

There are special tap removers, but they tend to be available at specailty supply shops, and don't always work.

You can use that hardness to your advantage. The harder a metal is, the more brittle it tends to be. I've shattered broken taps with a good sharp punch. Just keep punching at weak spots till you get most of it out. USE EYE PROTECTION. Of course in your situation you don't care if the threads are damaged. After it's out, have at it with easy out.

Another thing you can try: use the punch to spin the bolt out by picking at the outer edge of bolt, with punch slightly angled in direction you want bolt to spin. Don't get too close to edge or you'll peen the metal over and lock the bolt in even more.

Bolts have a lot of strenght when loaded in shear. A 3/8 bolt would probably carry 2-3,000 lbs like this. But it must be loaded; if the bolt is too long, the chain can slide out and that gives chain leverage to bend and break bolt. I like to use a longer bolt and thread a nut on. So you put bolt through chain, thread in as much as you can, then tighten nut so it squeezes chain and loads the bolt. I've never broken a bolt this way, even on the heftiest big blocks.

[This message has been edited by angel71rs (edited August 17, 2002).]

holmes677

thanks a bunch for all your help, i'll try what you said and let you know how it goes.