Broken Head Studs

[Joesmallwood]

Looking for recommendations in the Louisville Ky area to remove some broken head studs. Are there any resources locally or will I need to ship the block somewhere?

Thanks

[r lane]

It is not rocket science, but a lot of shops don't like dealing with wrestling them out, quite tedious and there are 24 of them and the possibility of having to drill and tap and incert. Kind of machine shop work. I am in Atlanta, but I would call shops in your area and ask, is this something you do or not. Bob

[Trackrash]

They will come out after applying heat from a propane torch to the area where the stud screws into the case. They are glued in and heat melts the glue.

If one is broken off at the case, weld a nut onto the stud and it will come out.

[Joesmallwood]

There are four left and they are broken close to the case. I’ve tried welding, but dilivar doesn’t weld well/at all. I tried grinding flat surfaces and using a stud puller, but they are too close. So, before I screw something up, which I am capable of, I would prefer to send this case to someone with experience in getting these out.

[mepstein]

Talk to your local machine shop.

[1987 Porsche]

How close are they to the case? On my rebuild I had one stud that broke and left me with about an inch. I used some Mapps heat, stud remover tool in pic below (Advance Auto) and attached my impact gun to it. Came right out.

Lou

[Trackrash]

Originally Posted by Joesmallwood

There are four left and they are broken close to the case. I’ve tried welding, but dilivar doesn’t weld well/at all. I tried grinding flat surfaces and using a stud puller, but they are too close. So, before I screw something up, which I am capable of, I would prefer to send this case to someone with experience in getting these out.

Yea, sometimes it is best to get the pros involved. I had good luck welding on the dilivar with my flux core, FWIW.

[Walt Fricke]

Electron discharge machining (EDM) is the final go to for broken studs. However, since you can insert the hole, you don't have to be as precise (EDM should leave the threads intact in the case), so you can use cruder methods. It is more of a machine shop which works on car engines than a Porsche repair shop that you are looking for, though your local shops which repair Porsches are apt to have machine shops to do that kind of work, and might tell you who they use.

[boyt911sc]

Originally Posted by Joesmallwood

There are four left and they are broken close to the case. I’ve tried welding, but dilivar doesn’t weld well/at all. I tried grinding flat surfaces and using a stud puller, but they are too close. So, before I screw something up, which I am capable of, I would prefer to send this case to someone with experience in getting these out.

Joe,

What is the shortest length of the broken dilavar head studs? A picture would be helpful. Thanks.

Tony

[safe]

When I replaced mine I dubblenutted the unbroken, put some manual tension on them with a spanner and heated the case with a mapp torch.
When it got hot enough you could feel when the "loctite" let go and they would spinn out quite easily.
Had to heat 30-45 seconds per stud.
If not broken flat with the case you should be able to remove them.

[mikedsilva]

Originally Posted by safe

When I replaced mine I dubblenutted the unbroken, put some manual tension on them with a spanner and heated the case with a mapp torch.
When it got hot enough you could feel when the "loctite" let go and they would spinn out quite easily.
Had to heat 30-45 seconds per stud.
If not broken flat with the case you should be able to remove them.

My experience has been exactly the same as yours.
In addition, I found that with the broken ones, I could grind 2 flats on opposing sides, and get a big adjustable wrench on there fairly well. Then use the mapp torch and eventually they would release.

I've also had success tig welding nuts onto the dilavar.. I'm a shocking welder.

[Joesmallwood]

Here are a couple of pics of the two that remain. I tried the tool above and was able to remove three of the last stubborn studs. The two remaining snapped again near the case. I will try again with more heat and maybe a helper to hold the torch.

[boosted79]

Check this out.

https://forums.pelicanparts.com/911-engine-rebuilding-forum/1021682-flush-broken-head-stud-removal-ez-way.html

[Joesmallwood]

Originally Posted by boosted79

Check this out.

https://forums.pelicanparts.com/911-engine-rebuilding-forum/1021682-flush-broken-head-stud-removal-ez-way.html

Excellent. I will give this a try!

[boosted79]

It looks to me like you have enough stud there to weld a large nut to them without the sleeve. You said that you tried that? How many amps did you run? You want it hot. The nut ID needs to be large enough to fit over the stud, ideally a tight fit. Slip the nut over the stud about half way and lay the wire in along the od of the stud to get it fused to the nut then fill the rest of the nut up with weld in a circular pattern. Start heating the case with the MAPP torch while you keep torque on the stud. When you feel it break loose start working it back and forth going a little more CCW each time.
Good luck.

[Trackrash]

Originally Posted by boosted79

It looks to me like you have enough stud there to weld a large nut to them without the sleeve. You said that you tried that? How many amps did you run? You want it hot. The nut ID needs to be large enough to fit over the stud, ideally a tight fit. Slip the nut over the stud about half way and lay the wire in along the od of the stud to get it fused to the nut then fill the rest of the nut up with weld in a circular pattern. Start heating the case with the MAPP torch while you keep torque on the stud. When you feel it break loose start working it back and forth going a little more CCW each time.
Good luck.

The key is to heat the case to melt the lock-tite. The threads themselves are not really tight. Any wire welder should do the job.

[Joesmallwood]

Originally Posted by boosted79

It looks to me like you have enough stud there to weld a large nut to them without the sleeve. You said that you tried that? How many amps did you run? You want it hot. The nut ID needs to be large enough to fit over the stud, ideally a tight fit. Slip the nut over the stud about half way and lay the wire in along the od of the stud to get it fused to the nut then fill the rest of the nut up with weld in a circular pattern. Start heating the case with the MAPP torch while you keep torque on the stud. When you feel it break loose start working it back and forth going a little more CCW each time.
Good luck.

I welded the nuts down over the studs and used a 110v (Miller 125) at the highest setting. It worked well on two of the studs, but the welds broke on a couple of the others. I then ground flats on the side and used the stud puller shown above. With this method the studs snapped closer to the case. I really think that the heat is the thing I am missing. I'll use a helper to hold the torch while I apply torque. This might be the secret....

[cmcfaul]

Vice grips, super tight. simplest is almost always the best.

Chris.

Got all mine out with a regular stud puller. No heat just elbow grease then installed case savers. Will never pull out again

[Classic11]

On my 1984 case i had two studs that were broken off flush with the case, there was not really a way to weld or grab anything. I had a local machine shop (atlanta area) machine them out successfully. No insert needed. If you are in the area let me know and i can give you his contact, very very good shop.

[mepstein]

Originally Posted by Joesmallwood

I welded the nuts down over the studs and used a 110v (Miller 125) at the highest setting. It worked well on two of the studs, but the welds broke on a couple of the others. I then ground flats on the side and used the stud puller shown above. With this method the studs snapped closer to the case. I really think that the heat is the thing I am missing. I'll use a helper to hold the torch while I apply torque. This might be the secret....

The secret is to hit the case inside, where the cylinders slip in, with map gas for 2-3 minutes, then remove the stud. Get the metal hot and it will loosen its hold on the stud. When I worked at the shop I did many cases like this. You won't damage the case or catch it on fire. The torque required to do it this way is a lot less than trying to unscrew them cold. I believe it's much easier on the case threads. It can easily be done by one person.