This is just my theory, but i think it could save everyone many headaches if they are planning on switching to head studs.
So I had a minor head gasket leak on my 81 rabbit with an 11mm 1.6d engine. I bought ARP head studs to use they are Part number: 204-4701, and meant for use on vw 8v gas engines. They were cheapest from LightningMotorsports.com, and they arrived very quickly.
first i got the head sat on and ran all the studs in to hand tightness
then i screwed all the nuts on to the studs by hand using a long extension with a 1/2" 12pt socket, so it was very easy to wind them on, no hang ups or anything weird, just made them hand tight with the extension.
after this, i went to do my planned torque sequence of 35ftlbs-70ftlbs-100ftlbs
35 was very easy, no qualms but i noticed that after i did #2 in the sequence the nuts needed to be spun down a little before they had any kind of tightness for the ratchet to work. so the tightness of the center 2 studs definitely effected the others
70 took a little more effort, and i noticed the same thing, that after the first 2 studs the rest became alot easier,
at 100, the trouble started!!!!!!!!!!!!!!!!!!!!!!!!!! the first stud was difficult how ever not impossible to turn, and i got it up to 100 ft lbs. the second stud how ever would not budge. i'll be honest, i have always been a scrawny guy, but seriously this one would not move, it ended up feeling like i was going to strip the 12pt shape of the nut so i stopped. and i was like well i'll skip that one, and i did 3-4-5-6, then went back to 2, and that nut wouldn't budge, i ended up half stripping off the 12 pt shape. so since that wasn't going well, i removed the nut and stud, the nut was very difficult to get off the stud, and when i looked inside the nut, all the threads were squared off.
My THEORY is that on that #1 stud, when the nut tightens down, it lowers the rear of the head, and this puts leverage on the second nut, since it is directly in front of it and well, i guess the head gasket is the leverage/pivot point, and the #2 stud is the opposite seat on the seee saw. and that leverage is too much for the #2 stud/nut and screws up the threads. This i have concluded after considering how much torquing one stud seems to effect another, how the outside bolts got easier and easier as i went.
So my recommendation, for all you stud wielders, is after 60-70 ft lbs, you should increase torque values in much lower increments, such is 5-10 ftlbs. though it is a problem which will probably only effect 1 in every thousand of us, the extra 20 minutes you spend torquing the nuts slowly, is well worth the time you'd spend trying to get a warranty stud and nut from arp or raceware.
This also happened to crazy andy, on the exact same stud, tho his engine was an aaz.
please take caution when tightening, and save your self the aggravation of a warranty process that i am about to go through.
first off, i would like to apologize for all the broken families and aneurisms that this thread which I have created may have caused.
Secondly, i'd like to let you all know that i deeply care about every single one of you.
The depth to which i care, is exactly why i am about to make a sacrifice, that many would shy away from. Many, simply do not have the balls to do what i am prepared to do for this community, whom i care so much about.
I will proudly wear egg on my face for you, vwdiesel.net.
the problem was my very own fault, as the nut tightens over the stud, the stud begins to stick up, i measured them at .240" above the nut at full tightness, and if you are not using a socket that is deep enough then obviously at some point its going to slip. this is why like i said on the stud i had a major issue with, i couldn't tighten it with out it feeling like it was going to strip. I failed to notice this is what was going on until today when i was retorque after warmup. i realize its been about a month and a half since i initially posted this, but between making time to work on it, and a few other problems i had, plus waiting on parts and stuff i just now got to retorquing.
so in closing,
i still believe much care should be taken when torquing with studs, how ever it is much more important to use proper tools.