Wormhole

I was able to remove all the head studs, except one stubborn bastard that I tried to muscle out and broke at the base of the block right where the treads start.

So far I’ve tried drilling a hole through the center and using a ¼ cone extractor with no luck. Two problems with the extractor, it does not have a drive socket (it’s a square head that no socket I can find will fit) and it’s not long enough to extend out the top of the block. A 5/16, 12 pt., ¼ drive fitted okay, but I stripped that in no time. I then had someone weld a 3/8ths extension to the extractor, but the heat must have distorted the metal and it broke. I have another set of extractors on the way that are a little longer, but I’m not very optimistic.

Can anyone give some suggestions? I do not want to Heli coil unless I absolutely need to.

Wormhole

Oh, and I heated the block with two mapp torches for 20 minutes. Didn't do much.

Dave951M

Did you drill the pilot hole all the way through the broken stud in the first place? I've found removing broken bolts and studs to be dicey if I didn't. I guess that it relieves radial stress in the bolt and makes it easier to remove. Past that, you might want to weld a bolt to the stud and try again.

mark944turbo

If I was in this situation I would be looking for a new block.

On the occasions where I removed head studs a little heat and a snap on stud extractor always did the trick.

Good luck!

adrial

Wow, that really sucks.

What about the open end of a 1/4" Extension? That fit some of the taps I bought...
Drilling a hole all the way through is a good idea. The bottom of the holes in my block were filled with loctite...they were very generous with the stuff at the factory. Maybe you could drop a chemical in there that dissolves or at least weakens the stuff (without damaging the aluminum...of course). And then push something the same size as the pilot hole (ideally with a rubber o-ring on it..) into the hole to try and push that chemical back up through the threads.

I would recommend time-serting over helicoiling, though your best bet is to talk to a machine shop. A time-sert can be made by just taking a high grade over-sized bolt and drilling a hole in it and tapping it for the head stud.

The problem with time-serting and helicoiling is getting the hole you drill to be dead straight with the engine still in the car. You'd probably have to take a block of steel and drill a hole in it on a drill press/mill and use that as a guide. Although now you're gonna need an extremely long drill bit. Also, you may have to open up the entire hole running down to the threads a little bit to get a big enough hole for a good timesert/helicoil...not sure if clearence with the water/oil passages is an issue there.

Where is the headstud that you broke (location on the engine...near #1 cylinder, etc)?

Good luck...
Seems like only one of us will have a running car at any point in time...

MHT

there are tap sockets available that have varying square drive sizes for different sized taps and extractors, a tool truck or possibly sears should have a set. Try to rent an oxy-acetelene set up and put some real heat to it, get a rosebud tip and get it real hot. Whatever you do, don't break an extractor in the hole. Use the largest one you can.

Peckster

Doesn't heating the stud make it expand and harder to get out. I think you want to gently heat the metal around it instead.

adrial

The alum block will expand much faster than the stud, so just heating the whole area would work.

Predator

Man, I feel your pain. I had one break about 1/2 inch below the deck. We ended up making a gig to hold a drill, and bolted it to the block. Then we used a cutting head to mill the bolt flat so we could get a drill bit started square and true. Using the gig, we drilled the bolt hollow, then used a home made easy out to remove it. All this was done with the engine in the car! Took some time to fabricate the gigs, but once everything was in place, it only took about 30 minutes. Drilling the bolt (man, its hard!) took the longest part of the operation. We vaccumned as much of the filings out before removing the bolt. Don't drill completely thru the bolt, or you'll have filings in the pan. Pack wheel bearing grease aroung the bolt to catch the real small filings.Once the bolt was out, we ran a magnet over everything, cleaned up the threads with a tap, and installed a new head bolt. Worked, and have had zero problems from that engine, and its now been in two cars and 100k + miles . Good luck.

cruise98

John:

If all else fails, find a local machine shop with an EDM. They can get it out with that. This would require removal of the block from the car of course.

If you are successful in getting an extractor in the stud, heat the stud, take some parafin (Gulf Wax from the grocer) and let it melt into the hole. This is supposed to break the bond between the locking agent and the threads. An engine builder I know told me this trick, but I have not yet had the occasion to try it. Might want to have a fire extinguisher handy whenever you use a torch!

Wormhole

Thanks for all the suggestions guys.

I thought the bolt hole doesn’t go all the way through. When I removed the other bolts the penetrating oil never drained out, or is that from the locktight at the bottom making a seal.

I tried that and just about every other possible combination. The ¼ is slightly off.

It’s the third stud on the top from #1.



I think I will try drilling all the way through, and maybe use the parafin cruise98 suggested. I’m picking up a few specialty tools, and several extractors tomorrow that will hopefully do the trick, along with the other suggestions.

Wish me luck...

adrial

The holes for the headstuds dont go all the way through, but they might if you drill too deep. I dont know how much room you have to play with there... I'll check when I get back from work, I should have plenty of pics.

Be carefull drilling through, you dont have much clearence from the bottom of the stud to the bottom of the hole in the block...

Mark the depth on the drill bit on one of the holes where you already removed the stud...make sure its clean of loctite at the bottom. You can tell by how it sounds when you stick something in there.

I like the parafin idea, great trick if it works.

Good luck

Jakerx

man i feel your pain my friend.... i had plenty of things go wrong with my rebuild (regarding studs and stripped nuts, etc)

scular

Were you successfull. I just had this happen to me, and was wondering if you had any luck. Also does anyone have any other ideas.... It is a real pain as my stud bolt broke all the way down at the threads.

Thanks,

SCular

Wormhole

Don’t bother trying to get it out, I tried everything and it’s near impossible. However, My machinist came up with a real creative solution, he made a bushing that screwed into the block, above where the stud broke (the treads don’t start until about 2” into the block and that’s where mine broke). He then cut a stud and tapped it onto the busing. It’s been about a year with a lot of track time and head removals and I haven’t had any problems. I actually think it holds better then stock.