Head Stud Removal

[andycook]

Need some guidance here guys please. I am removing my head studs preparing to prep the case for reassembly. I got all but three of the studs out with a stud remover. The last three will not budge. They are just twisting. I am working them as close to the base as I can get too. Any odeas on what I can do to help them along? Thanks in advance.

[Rondinone]

Are you using a blowtorch to heat the case?

[andycook]

Nope, haven't been. That was just recommended to me. I am new to the Porsche scene, and wasn't sure how durable the cases were. Thanks for responding.

Andy

[Rondinone]

I found the most effective place to heat the case was near the bottom of the stud, just inside the cylinder bore. If you're using a plain propane brazing torch, keep it there at least 5 minutes; one of my stubborn ones took 10. Try not to heat the stud itself, but only the aluminum case.

I tried a few studs without heat just for kicks. Only one would move.

[andycook]

Thanks. I'll give it a try tommorrow night. Wish me luck!

[john walker's workshop]

there's tons of stud removal tips if you use the search feature. an oxy/acetylene torch works the best.

[David]

Oxy-acetelyne is best but if you have to buy something and don't want to spend hundreds of $ you should try MAPP gas instead of propane since it burns hotter.

[tony77targa]

Hey Andy
you decide to rebuild that 3.0?
What do you plan on using for head studs?
I got a 3.0 core and I am tearing it down now it has 1 broken head stud and am planning on replaceing them all but not sure with what..

[tgarnoldo]

I just rebuild my 3.2 and used both ARP head studs and rod bolts. The quality is superb...

Arnie

[andycook]

I think I am going to go with steel. Not sure yet. Yeah Tony, I think I am going to go for a rebuild. I'd like to catch up with you sometime to see your car. Thanks for all the responses.

[markwemple]

Hey tony, I'm doing a topend and, don't know if I'm stupid but, I'm going with a lot of strong suggestions to using the old steel ones. I will only be replacing the bottom ones, read dilavar, as suggested by several very good places including CE. Just a thought.

[Wayne 962]

Get a copy of the Engine Rebuild Book - otherwise you're driving blind (the torch tip is in the book).

-Wayne

[garibaldi]

What you would be best to do is to heat the case in an oven to kill the Loctite bond on those studs. That way you will not have drastic temperature fluctiuations through the case by using a torch in only one spot and you will cut down on the chance of thermally shocking and distorting the case in the critical region of the cylinder spigots.

[Doug Zielke]

Well, there sure must be a lot of "shocked" and "distorted" cases around, eh?

John Walker has posted many times how to use the torch on the studs.
It worked for me no problems, as I'm sure it has for countless others.
(I use my oven for baking lasagna.)

[andycook]

The torch worked fine. One problem child but that's another story. Thanks for all the responses. Greatly appreciated.

P.S. Wayne, I already have your book. Refer to it often, but didn't see this.

[garibaldi]

The torch method works fine and has done so for years, not saying its absolutlely wrong, but if given the chance, I would rather heat the entire case evenly rather than localized heat, just less chance for distortion.

[Wayne 962]

Originally posted by garibaldi
The torch method works fine and has done so for years, not saying its absolutlely wrong, but if given the chance, I would rather heat the entire case evenly rather than localized heat, just less chance for distortion.

Have you ever tried this method yourself?

First of all, you must get the area of the case very, very hot (typically a propane torch will take a long time to get it anywhere near hot enough). Oxy torch will heat it very hot, in a very localized area. Secondly, I doubt that most people own an "oven" large enough to put an entire engine case (complete with studs) into. Thirdly, you'd better have some pretty big oven mits to remove that thing. Finally, you're theoretically supposed to locally heat the case inside the cylinder spigot, not the stud, otherwise, the stud will try to expand further into the hole.

-Wayne

[Wayne 962]

Originally posted by andycook
The torch worked fine. One problem child but that's another story. Thanks for all the responses. Greatly appreciated.

P.S. Wayne, I already have your book. Refer to it often, but didn't see this.

The torch method (and precautions) are on pages 36 and 37, FYI...

-Wayne

[garibaldi]

I knew this was coming.

To begin with, yes, I have done this method. I find it faster, easier and more effective than using a torch. I have used a torch before, but I now just put the case half in a stove and let it get to temperature. And yes its gets, in your technical term- very, very hot. Hot enough for the studs to come out without a hitch. The intent here is to warm the case to alleviate the loctite bond, not melt the aluminum. The problem with using the torch is that you must use more heat in that area since the case material is constantly pulling the temperature away from the area trying to equalize, so you need more heat from a flame than you would if the case were evenly heated as a whole.

You say very, very hot. How hot is that? Using the method I describe, there is control over the temperature.

The other added benefit to heating the whole case is that you can help normalize and relieve it. We have gotten motors where copious amounts of welding was required to repair them- we leave parts on the heat for days to get it to calm down both before and after so that they will normalize and stress relieve.

I am not telling anyone to use their home oven, that isnt the point, the case probably wouldnt fit. I said if given the chance, I would rather do it that way. What you need to do is gather information from people who would have the opportunity to do either way and then respond. Problem is, that I am sure hardly anyone uses the latter method since almost every shop has a set of torches and not an oven.

You say that "Theoretically" the case area inside the spigots should be heated. Whos theory is that?

Lastly aluminum and magnesium have an expansion rate far greater than steel or steel alloys, so the fact of heating both the studs and the case together means relatively little since the case material will have expanded a multiple of times further than the stud would. Which brings me to this in closing- the idea is to remove the stud, the stud is secured with thread locker, which is the major retaining factor, the temperature is supposed to break the locking bond.

Wayne, I would like to stop here.

[Doug Zielke]

Originally posted by garibaldi

.... I would like to stop here.

Please do.