pind

The hole is to allow for extra "shrinkage" of the bolt as it cools. If you use an appropriate size bit, it also allows you to reach into the center of the bolt, and run a "bead" as such up one side of the hole, which shrinks the bolt even more.

Ever welded a bearing race out??? Same basic principle, different application.

Works even better on larger bolts.

Another dumb trick, drill the bolt, heat it to dull red, and hit it with a shot of that -50 in a can electronics cooler. Use the straw, so it hits the inside of the drilled opening, then back it out with an easy out.

Easy out, by the way, is the single most mis-named tool on the planet...

That sort of clear things up?

Have fun

On edit, J. I don't don't do facebook either. Find that if there are people I want to talk to from my past, I'm generally still in contact with them. If I didn't want to talk to them back then, why would I want to now?? Keeps things simple.

sherod

I've also used the "weld" to pull engine sleeves.

capt.Ron

I did try that. Darn thing still wouldn't budge. I didn't think of using a mig to get down in there. This stud was quiet small. 5/16 dia. I was really worried that id weld the stud to the head.

pind

If you use .035 inner shield "flux core" wire, you would have to work at it in order to make it stick to the casting. Not saying it can't be done, it is just difficult. If you are really worried, spray some spatter release compound on the casting before welding.

capt.Ron

Got er done.
Lots of loctite. Hopefully it won't leak. Pretty sure it wont pull out of the head!!

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Another secret. Any time you drill into a broken bolt, use a left handed drill bit. Most of the time it will go in a little bit then simply unscrew the bolt for you and it's over.

capt.Ron

I looked high and low for left handed bits. Couldn't find any.
As stuck as this bad boy was I'm not convinced that would have worked but ya never know. I rotated the engine on the stand so I could fill the bolt hole with PB Blaster. I let it soak for a couple of days and it still wouldn't budge.

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McMaster Carr will have them You'll have to order them