Head stud refuses to remove!
 

I've started trying to remove the head studs from the motor. THe first 8 came out nicely with heat and using two jam nuts. Problem is, the last 4 on one side will not come out. I heated the case well with propane...

Tried jam nuts (stripped the threads) and tried a cam-lock stud remover (won't grip).

What now? (I guess welding a nut on?) I'm NOT a very good welder and only have a small oxy-MAPP system.

You are on the right trail. Weld the nut on well and heat the heck out of the stud. That red lock tight needs really high temps to melt. Once below block level it gets real tricky. Good luck.

Diverdan

Propane isn't hot enough. Read john walkers reply in the following thread.

http://forums.pelicanparts.com/porsche-911-technical-forum/64501-broken-head-stud-need-advice.html

I was trying to only heat the case... SHould I heat the stud too? WOn't that expand it and make it harder to remove?

The heating and cooling of the stud is what breaks the Loctite (or rust) loose.
Go at the job slowly and run the studs through a couple of heat cycles before you put pressure on them.
Good luck
Bob

Don't heat the stud, heat the case only.

http://forums.pelicanparts.com/uploa...along line.jpg

you have to use an oxy/acetylene torch. the double nut method sometimes can't quite get a grip on the tight ones, and a stud puller tool is needed. keep tension on the stud as you heat the case and when you feel it start to move, keep the heat on for a few more moments as you continue turning the stud.

John is exactly correct, but I did not need any fancy stud pullers. I may have double-nutted them, but one was broken so I used vice grips at least once (if not twelve times). Heat is the key, and propane will not get you even close. Five full minutes of propane heat against an aluminum case will barely even make it warm. You need oxy/acetylene. About 30 seconds of oxy/acetylene heat and you will feel the loctite come loose. Keep heating while you gently unscrew.

And all that heat doesn't warp/damage the case?

Chris 12 - Head Studs - 0!
 

Well thanks everyone. The new tally is Chris 12, head-studs zero.

I couldn't bear to use oxy on the case... i just had bad images of turning the case to slag.... (Trust me, I'm NOT a proficient welder)

So I used a rosebud type tip on my propane torch, chased the damaged threads on the studs with a die, double nutted them, and then welded the nuts on the recalicrant studs.

I'm grinning from ear to ear!

On that note, taking apart this engine has been great so far. I've NEVER done this before so it's been very educational and rewarding... Prior to Porsches I managed oil changes and tuneups... I've got a box full of bagged, tagged and labeled parts and looking forward to this winters re-build...

What does Esther think of your pile-o-parts???

:)

Well that basement room was pretty much dubbed the relic's of racing room so I imagine she's just happy it's not in the living room :)

She's on board for more horsepower too, I think she got tired of me getting blown away on the straights... :D

My experience with 3.0 cases is somewhat limited however I helped a friend remove a couple of broken studs from his.

We took it to a mutual friends machine shop. He heliarced a nut to the broken off portion of the stud. He let the nut cool a little. Then he lit up a rose-bud tip on his acytlene torch. He said to apply pressure to the stud with a pair of vice grips on the welded nut. I asked him how long are you going to heat the case? He said he would heat the case till it got "mushy". In applying a good bit of pressure to the stud/welded nut while he heated around the base of the stud boss it suddenly began to move. He said keep moving it! I did and the stud came out of the case.

With the a number of Donavan and Millodon engine cases laying around his shop, I figured he knew what he was doing.

Good luck,
David Duffield

Mushy? That's scary stuff.

I finally got tired trying to crank on Jam nuts, and just welded nuts to the remaining studs since I'm replacing them anyway. Came off like a charm.

Chris Streit 24, Head Studs 0.

I'm certain that he meant the loctite gets mushy, not the engine case. Can the case be melted? Probably. But you'd have to do it intentionally. Can the case be heat-damaged by a reasonable person in the act of removing head studs? No.

I worried about this too. Apparently, one of the characteristics you're dealing with here is the ability of aluminum to transfer heat. Aluminum is VERY good at that. So, it is neigh on impossible to get the case hot enough to distort. Not impossible, but it's not going to happen in the time it takes to remove the studs.

I'm assuming you're talking about the upper studs, as it is very difficult (if near impossible) to weld to Dilavar. Also, I don't recommend removing the upper studs - there really isn't any point (unless you have a Turbo, as these are Dilavar too)...

-Wayne

This is a goofy question, but the upper studs don't break and don't need to be worried about?

No. They don't break.

As I will be removing the Dilavar studs on my 3.0 in a short while,
I really appreciate JW reminding us of the technique. He's a mean dude with the oxy-ace torch! :)

I removed them all for replacement. All The studs had rust and corosion... I'm not going to take a motor down to nothing and then re-use these studs... Yeah, they'd probably be okay, but I'm going with new ones to be sure.