Broken Head Studs
 

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

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

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.

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.

Talk to your local machine shop.

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

http://forums.pelicanparts.com/uploa...1577908622.jpg

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

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.

Post picture.........
 

Joe,

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

Tony

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.

http://forums.pelicanparts.com/uploa...1577973087.jpg
http://forums.pelicanparts.com/uploa...1577973179.jpg

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.

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!

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.
http://forums.pelicanparts.com/uploa...1577990664.jpg

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....

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

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.

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.

Heat the case around the stud like the others are saying, at which point my engine builder and myself flowed a bit of bees wax onto the stud that wicked into the threads. Hardest part was finding a "real" piece of bees wax. Best I could source was a Berts Bees lip balm (like a chap stik) with peppermint. It had the most bees wax of any of the Berts products. The studs smelled dandy coming out. Keep the heat on while you are turning the studs out, otherwise they tighten right back up.

dilavar is not the easiest to weld to its finikey with a rosin core mig .. i ran a few test welds on some already removed studs. as most if mine broke when i removed the nut but all broke up high but two. What ended up working the best i was able to get a solid weld with my tig welder i got the stud cherry red and kept feeding in the rod until it was full across the top then i heated the inside of the case on the stud and applied steady constant pressure just enough so it flexed but didn't break it took quite a bit of heat but the stud eventually let go..i highly recommend doing some test welds with old broken studs in a vice prior to the actual low stud removal weld.. this way you get a feel for the breaking point of the stud and don't over stress it. all the studs came out easy without heat but 1 the stubborn one took a good 3 or 4 minutes of medium even heating heating with a b tank until it finally let the stud go .. its a two person job one to heat and one to apply even pressure on the nut welded to the stud ..

Most of you guys had better luck than me.In all 6 broken studs.
We used Heat.A lot of heat.Studs still broke.A few we Tigged on nuts, either the weld broke or the stud did.
Various tools used.The best was a snap on Stud remover.Or a pair of Stillsons.
We even turned case upside down, holding stud in vice then applied heat.Still broke stud.
4 broke twice, second time at case level.I called out my thread guy Clint.He spent 3 hours drilling out the remnants and managed to save every thread.
He makes 90% of his living with Porsche stud/nut removalhttp://forums.pelicanparts.com/uploa...1578215384.jpg

I got my Dilivars out with a small pipe wrench and heat.

I was able to get all, but three out with a combo of things - pipe wrench, stud puller, and/or welding a nut on the end. There were three that I simply couldn't get so I took it to a machine shop where it could be managed a little better with proper equipment. I don't like to admit defeat, but I felt it was the best option. :(

Defeat is when you work beyond your abilities and hurt yourself or the part. Taking it to an expert before you are defeated is being smart.

If the studs are broken close to the case I take the case to the EDM people , not that expensive and no damage whatsoever .

A local EDM guy is probably safest. If I recall aluminum expands about 13 millionths per degree Fahrenheit, but don't quote me.

My acetylene torch has been a best friend for many years

Removed with following equipment everything from spending hours on board:
1. 1/4 inch bolt and nut remover for broken stud, around 1/4 inch above spigot was the top of a broken stud, tool worked perfectly, eats right into dilivar and steel.
2. 5/16-8mm for non-broken stud, damages threaded stud end, worked on all 22.
3. MAP Max Heat Torch Kit, Benzomatic (65$)
4. Apply heat to inside of spigot, earliest to come out was 25 thousand count, longest was 170 thousand count, 3min? My 13 year old son did excellent heat work. I would apply torque to socket wrench every 10 thousand count or so to check for movement, if no movement then relaxed in a waiting position with socket and wrench still in place. When it started to turn, I'd ask my son to pull back the heat, then when it was clearly coming out easily we'd shut it down.

For those in Canada, the bolt buster was nothing more than the Canadian Tire Maximum impact bolt & nut remover set. Paid 23$ bucks on sale. Careful with the spigot with studs that are broken 1/4 inch or so above it, I added a spacer washer inside the nut remover tool so that the end of the socket (closest to case/spigot) could not come in contact with the spigot. First try on threaded nut and you'll see how the fluted threads cut down and force the socket onto the stud. I also used a Dremel to even out the tops of the two broken studs before starting. There seemed to be clearance between the outer spigot wall and the nut socket, but I added the spacer washer just in case. Be aware of this. Sorry if it's too late for your work, but it may help another, I just wanted to give another thumbs up to these nut buster sockets as well. I think Irwin has the same thing, there is a youtube vid, that's where I got it from originally. Though I used heat as well, this forum.

Phil

To show detail of tool bite in and how far down the socket it goes. There seemed to be enough space between the socket outside wall and the near spigot wall (I thought a little could be shaved off the spigot wall in that area, you'll see when you get there, but probably not necessary) so that you might be able to actually remove broken studs that sit at or below the spigot height. Be careful once again, not to drive the socket into the case or spigot, I put a spacer/washer in the socket itself, etc.... you'll have to figure it out.



http://forums.pelicanparts.com/uploa...1581016617.JPG

The issue I ran into is that I think its corrosion between the stud and the case, not necessarily the loctite.

Any ideas?

I have had great luck with impact guns. Set at low torque, penetrating oil, and let her rip for 5-10 minutes. Just the vibration loosens it over time...

Any relation to Gaylord?

Sorry, I had to ask

heat, heat, heat...

No, Martha.

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Dont give up! After a week of sweating it, finally got all my broke one out.

Got mine out on a 3.0 930/10 with a mix of acetone/atf fluid mixed 50/50 soak for 24 hrs, heat the spigot with propane torch for 5 mns and then pipe wrench, they all came out no damage.