heat is your best friend, just removed all 12, no issues, some even look brand new with coating still intact

I have 1/2 of my second gear glued to the side of my tool box.....

Hey, your garage looks like mine! If the rest of the bug is as nice as the front fender, that looks like a really nice car! Now we're really getting off track.... :)http://forums.pelicanparts.com/uploa...1366807905.jpg

You're not a real air cooled 911 owner til you've enjoyed spending time with broken head studs. I went Supertec so that it won't happen again & again & again

PS. What moronic mechanic would replace just one head stud?

You just havent LIVED unless you have suffered a broken headstud

[IMG]http://i1311.photobucket.com/albums/...ps0d4aea42.jpg[/IMG]

And I carry it around in my pocket ........not sure why

FWIW, "Divilar" and "Dilivar", if accurately identified, are knockoffs of genuine Porsche Dilavar head studs. As such, they're not the real deal and probably made from some inexpensive, not-to-spec, good-enough material. It's like a "Rolex" watch that lasts 2 weeks. Rolex doesn't like knockoffs. Neither do unsuspecting consumers.

If it's merely a misspelling on your part, you could have an earlier version of the real thing (black coated are version 3 or 4). The fully threaded versions (993) are the latest. I think Dilavar studs were offered in at least 4 versions through the years including a defective batch from the factory.

Sherwood

Good post! Brought back a memory about those after market/dealer defective studs. My shop learned that the 911 guy at Ogner P&A had assembled a 911 engine including 12 new lower studs. The story went that, late in the day, the technician installed the heads/cam towers, torqued the heads, cleaned up and went home. The next morning, to his amazement, he found no fewer than two of the studs had broken during the night, and their ends were lying on the floor under the engine. Talk about a WTF moment!

What we never learned was if the defective studs were from inside the dealer system, or were they bought outside from a wholesaler? We knew of a second case that was similar, and we knew that our primary source for wholesale purchases pulled a large quantity of studs from their inventory. We also never learned if those studs were o.e., or a knock-off.

Very worrisome time, during which my shop did a couple stud replacement jobs, but we bought our new studs from a dealer (not Ogner) that was convenient to my shop. I think that I "held my breath" for a couple months, but both cars returned for their 1,000 mile service, and neither ever had a problem. Whew!

I wish mine was that short. It broke very close to the case.

It's too long to carry in my pocket ...

Dilivar death
 

Rokemester, where r u located?
I too have beverages in the garage. Can't do good work without refreshment. The stud replacement will take a long time. I'm planning a full rebuild and that's going to take more money than I can think about without beer.
The stud removal should be within my pay grade....I'm an old machinist....very old.
I will soak them for a couple of weeks (Kroil ?) then use propane heat and magic spells to get them out. If I'm successful I may hire myself out for refreshments.
If not successful I will hide from the world.

Hmmm, now you've got me thinking! I need to do some homework and get back to you on the Divilar vs. Dilivar. Could just be my uneducated Porsche brain or early onset senioritis. See anodized vs. zinc coated brake calipers earlier in the thread. I'll get back to you all on this one.

Again why I love this forum! You can always find a silver lining. I have a shorter broken head stud than the average guy;) I suppose a disadvantage depending on what forum your in. Oh yeah we're talking Porsches here. There I go again hijacking my own thread!

From Northeast Ohio, near Cleveland. I finally figured out how to add a bit more detail to my signature after 80+ posts (slow learner). Oh an old machinist, WOW could I use your expertise around here! +1 on the rust penetrant and TIME. What's the rush? Oh yeah the driving season is just getting good.

Love the garage. Life is just not quite complete without a VW Bug, Bus, Ghia or Thing in the garage. The 911 and Bug coexist quite nicely and the Bug (Murray) is particularly happy because he's getting a lot more attention and drive time while the the Targa is down and out.

Concentrate! Back to the head stud!

http://forums.pelicanparts.com/uploa...1366846506.jpg

OK By me.
I often feel a pair of nuts when I reach in my front pockets.

Tomato, tomaaato, dilivar, divilar, dilavar. Should have been "Another broken dilavar head stud sob story" My bad! I really am not that bad of a spellar...speller.

Having different headstud material on top and bottom......stupid freaking idea.......just sayin'.....

They say blindness follows if this practice is excessive. .... or something like that. :-)

It sure has me confused!!! I suppose it makes sense to have head studs that cool and heat up at the same rate as your case if your driving your 911 daily...and like you stole it. Me, I'm just the typical late 50s kid that always wanted a real Porsche (had a 75 914 which I loved and had to give up when the kids started to go to college, but I digress). I drive the Targa whenever I get the chance and then it goes into the garage for the winter with mega salt on the roads here in NEO.

By the way here is a great post from some guru on the genesis of dilavars:
Head Studs? - Rennlist Discussion Forums
Believe me I've been doing some homework.

Porsche engineers may be myopic on occasion, but seldom outright stupid. There was a reason for those different materials. Something about different operating temperatures/environments top and bottom. Don't put them in the same category as GM or Ford and others. I only wish for excellent hindsight when I'm creating/designing new stuff. :-)

Sherwood

They had a need to fix a problem....a long standing problem....they made a wrong decision.

They screwed up the 2.7, then made a stud change for the 3.0. How many years was that span?

I will admit that the 2.7 was hosed by the US EPA and the studs pulled because of the add on smog/thermal reactors excessive heat. But the 3.0 had an air pump....no TRs and a different case.

They made a bad decision with the 3.0 and never manned up on it. Kinda like Bentley never admitting that they made the firing order bassackwards.