Broken Head Stud

[swackdog]

I am replacing all of my head studs with steel studs because two of them were broken -- #4 & #6 exhaust. All of the old studs came out fine except one of the #5 exhaust studs (Dilivar). Unfortunately, it snapped off just 1/4" above the lip of the case.

What is the best way to remove the rest of this stud? Can I drill out the stud and use a screw extractor to remove the rest of the stud after heating the case with a propane torch?


Jim
1981 911SC

[kstylianos]

Jim,

Use the Snap-On collet type stud extractor for this job. Cut 10mm threads on the end of the remaining head stud, thread the extractor on and TIGHTEN, then extract. Easier said than done, but this method worked like a champ for us with 2 similar broken studs. If it still dosent want to budge, heat the inside of the case where the stud is threaded to melt the factory loctite.

EDIT: Sorry, just read only 1/4" inch remaining.....you sure that's all you have to work with?

[john walker's workshop]

if you have 1/4" you are lucky. the case should be heated as normal with an oxy/acetylene torch. i've had good luck getting these out by getting a real good, TIGHT grip with large visegrips. trouble is, you have to clear out the upper studs and case thru-bolts and nuts that are in the way of swinging the visegrips, so you don't have to release and reclamp the stud continuously. also be careful not to gouge the cylinder base as you turn the visegrips. heat well, until you feel the stud start to turn, then keep the heat on the case for a while as you slowly turn it out. try to position the visegrips so you can get largest the swing before you hit something with their handles. if you could put the visegrips on a slight angle, you may not have to ever remove and reclamp. a hot case is the ticket.

[jgparker]

I was able to get this one out with a pair of vicegrips:



good luck

JP

['78 SC]

I removed all 12 exhaust-side studs with these gizmos from Sears. The #4 fits over the threaded ends of whole studs and the #2 fits over the unthreaded remains of the broken studs. It worked well even on stubby remains (slightly shorter than shown in the previous post).




If the end is broken at an angle, you may want to square it a bit with a Dremel so the gizmo sits straight. Tap it with a SFH to seat it so it bites into the stud. Use an air wrench instead of a breaker bar (more twisting, less bending).

I removed mine cold, but heat could only help. (I did have two of the longer ones break). The only ones I couldn't remove this way were flush with the case and had to be machined out.

YMMV, good luck.

Steve

[sammyg2]

SFH, LOL

[rothaus]

Any good tips on studs which are snapped off just about even with the case (just sticking out a few milimeter). I got all out, but I still have 3 in, which of 2 were already snapped of when I took the engine apart, and one I did.

O boy

[safe]

Maybe you can weld a nut on it. It doesn't have to engage the whole nut, you weld inside the nut, pleanty of heat...

Heat the case and use an impact wrench.

[tom1394racing]

Tapping threads on the broken end then using the collet tool has worked for me every time.

[rothaus]

I got them out. Welding worked actually better as I expected. Thanks Magnus !

The one I brocke because I did not heated it long enough was the worst one. since it was almost even with the case.

The 3rd nut finally stayed on.

Here some pictures, I'm sure I will not be the last one who will look for this, and I hope it will help others as well.

The one right in the picture is No. 1 the shortest one.





Welding on the nut for the second one


Heating at least for 10 min if you have only a propan torch.


Here are the left overs. the left one is the one I had to weld the gap between the end of the stud and the nut.



I hope this will be helpful.

Happy New Year
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[faverymi]

I would add that using MAP gas save me a lot of time per stud.

I heated them for about a minute and they came right out.

[Bob Kontak]

Originally Posted by rothaus

Heating at least for 10 min if you have only a propan torch.

Thanks for this info- I could not get mine to budge 13 years ago and decided to take the case to a machine shop. They only charged $100 but now I know why they did not move. Not enough heat for a long enough duration.

Subsequently I learned about Maap gas and even bought a kit that mates Maap gas and oxygen for a pretty good bluetip wrench.

[Eagledriver]

Welding on a nut has the added benefit of heating the crap out of the stud, this releases the loctite. It's my method of choice.

-Andy

[safe]

Good work rothaus.

I had one broken stud that used this method on last sumer.