Head stud install

[4sd911]

Got my case back (2.7) from Ollies today, and I'll be reinstalling the head studs do I use a collet for this? I know collets remove studs do they also install?

Ollies removed the case timecerts and replaced them with case savers. The studs removed are 993 dilvars and will be reused. Most of them still have the timecerts on the studs. I assume the best way to remove the cert would be with 2 collets, one to hole the stud and one to remove the cert? Also will need to apply heat.

Some of the micro encapsulated paint on the studs is coming off I assume this should be repainted?

Should I use red (271) loctite on the head studs, or is medium grade blue OK?

[Flat6pac]

I wouldnt use red on anything although the factory used thread seal on the 993 dilivars that really worked well, the temp change of the threads while inserting was enough to activate the locking. needed a torch to loosen them
Bruce

[Wayne 962]

I would use the blue Loctite - the studs backing out are not exactly the failure mode of the 2.7 and with the timecerts in there, you will have Dilavar stud / steel insert contact.

I would use a collet on the stud, and then just a big set of vice-grips on the cert. If that doesn't work, nick the outer edges of the certs with a Dremmel tool until you can separate the crack you just made with a small screwdriver.

-Wayne

[4sd911]

Sounds like a good plan, I'll give it a try.

[Carrerax]

Originally Posted by Wayne at Pelican Parts

I would use the blue Loctite - the studs backing out are not exactly the failure mode of the 2.7 and with the timecerts in there, you will have Dilavar stud / steel insert contact.
-Wayne

Would you also use Blue on a 3.0Sc case when putting in new steel studs?

[Walt Fricke]

Ordinarily, you don't need a collet to install head studs. Fingers often work. They aren't usually bottomed by the time they are screwed in to the proper height. Which is one reason we are tempted to use a thread locker of some sort.

I don't use the barrel nuts, so I have lots of spares and made a tool from one of them. I drilled a hole across one about in its middle, and stuck a nail through it. Screw it onto the stud until the stud bottoms on the nail, then use a hex socket to do the screwing. When done, the tool should unscrew easily. Quicker than collets or double nutting.

This also allows you to deal with a head stud which had unscrewed itself in an otherwise intact engine.

[Tom F2]

The Loctite strengthens the threaded bond, as well as keeping the stud from backing out. I would go with the red, because that is what Porsche specs, and it is for a high strength application. On the other hand, if all you have is blue, that stuff is pretty strong, too!

Biggest mistake I have seen is carelessness with setting the stud height. To get the correct fit of the internal hex head bolts, the height has to be just right. Check the spec, but I recall that 161.5 mm from the machined surface where the cylinder sits is the correct height. I don't know about his later edition, but the original Bruce Anderson book gives the wrong height.

[Carrerax]

Thanks Tom!

[Walt Fricke]

No, no. 135mm is the installed height spec.

This is engraved in my brain (and I checked with Wayne's book, which repeats the factory spec, as the brain has too much in it to trust on details some times) because of my failure to follow Tom's underlying advice back when. I just screwed them in until they bottomed, and some were too deep and I compensated with thinner washers. Others stuck out too far, and the inhex spit out the tool before torque was obtained and I fussed around with adding extra washers. Not a good show on my part, and all due to carelessness. Ignorance also, to be sure, but careless not to take the time to find the spec.

Walt

[4sd911]

The timecerts came off fairly easy with the application of heat from a propane torch. While the paint on the studs wasn't damaged from the heat it's mostly just peeling off. The plan will be to repaint using a firearms paint that can take 1600 deg. f. Would it also be a good idea to have them re cad plated first? Screwing a few in the case they tend tighten at about 137mm, so I think I'll use the blue loctite as they will need a bit more that finger tight to get them to the 135mm mark.

[gregwils]

Finger tight? I have a completely different scenario. I am installing a set of steel exhaust side. I am using a double nut and running into serious resistance. The last one (8 more to go) required heat and a breaker arm bar to get to to about 135.5. I am actually concerned I don't damage the threads on the barrel end from tightening the double nuts as much as required.

The thought of running them past 135, then backing them off seems impossible to me. Does the collet allow significantly more torque to be place on the stud?