Are steel head studs bad?

[Jhogan0101]

What kinds of problems can these cause?
I know the 993 dilivar 2.0 studs are better for thermal expansion but not sure its worth the extra $900.

[chris_seven]

What type of engine cases?

[Jhogan0101]

3.0

[boyt911sc]

Jhohan,

PM me and I will direct you a well respected Pelican member that is a good source for steel cylinder head studs. Bought several sets from him before and will be getting another set soon for the next engine rebuild project/s.

Tony

[Flat6pac]

The broken studs are not steel...
Bruce

[cabmandone]

I put ARP's in my 3.2 after I found two of the dilivar studs broken on the #6 cylinder. And to be honest, the only reason I didn't go with Henry's was I got free two day shipping with a nephew's prime membership. If time hadn't been a factor I'd have bought from Henry hands down for what he does on the boards here.

[Dpmulvan]

Pulled my 3.0 every single dilivar stud was broken.

[cabmandone]

Originally Posted by Dpmulvan

Pulled my 3.0 every single dilivar stud was broken.

Wow! that thing had to be loud! And not run all that well either.

[Jhogan0101]

Dpmulvan -993TT dilivar or original?
Yeah Henry is the man. Was also thinking about getting those studs.

[boyt911sc]

Originally Posted by Dpmulvan

Pulled my 3.0 every single dilivar stud was broken.

Could you count? Just kidding. I don't think the engine could run without flapping or damaging the cylinders with all the lower cylinder head studs broken (?). Do you have a picture of the twelve (12) broken studs? This could be record breaking performance.

Tony

[cabmandone]

Originally Posted by boyt911sc

This could be record breaking performance.

Nice!

[Dpmulvan]

I'm serious every dilivar stud was broken no joke. Engine was out of the car when I got it but amazingly there was no cylinder blow by. The case went to scrap because it had damage however grip911 did drive down from Montreal with a new case and he should be able to vouch for me. The motor had sat since 97 so I'm thinking maybe some broke after the car was parked. I gave the case to a neighbor to scrap it if he still has it I will try to get a photo.

[Dpmulvan]

The dilivar studs in question where out of a 1980sc with 100,000 on it

[Henry Schmidt]

Head studs on air-cooled engines is about cylinder to head stability.
To build reliability and a stable platform for performance Supertec head studs offer the best all around clamping consistency that we've tested. We tested Raceware, ARP, Dilivar of every iterations and even a "Super Stud" sold as a Dilivar replacement by some of the wholesale outlets. The testing of course started with stock steel Porsche head stud and nothing even comes close to our design.
Add ease of assembly, unique design, unparallelled quality and a life time guarantee and Supertec stud heads are hard to beat.
And then there's the price that has remained consistent for 12 years.

[boyt911sc]

Originally Posted by Henry Schmidt

Head studs on air-cooled engines is about cylinder to head stability.
To build reliability and a stable platform for performance Supertec head studs offer the best all around clamping consistency that we've tested. We tested Raceware, ARP, Dilivar of every iterations and even a "Super Stud" sold as a Dilivar replacement by some of the wholesale outlets. The testing of course started with stock steel Porsche head stud and nothing even comes close to our design.
Add ease of assembly, unique design, unparallelled quality and a life time guarantee and Supertec stud heads are hard to beat.
And then there's the price that has remained consistent for 12 years.

Henry,

Your Supertec head studs maybe the best in the market. I don't question that as you claimed. But I am just wondering if you have some technical information or test results that support this claim. As you have mentioned, you tested the other products too. I would like to try your cylinder studs for my next project. Thanks.

Tony

[tom1394racing]

I have never seen a broken steel head stud. On the Magnesium cases, the studs will pull out of the case but steel studs do not break. Time cents are the solution for Mag cases. For a stock rebuild, OEM steel studs are a good and sufficient cost savings option.

[cabmandone]

BTW, If you want to save a nickel, I'll give you my old steel top studs. I think I still have them. Tops are generally steel, bottoms dilivar. Depending on what your plans are for your car/engine combo you might consider just putting used steel in it if the 3.0 is a stepping stone engine with plans for a bigger engine in the future.

[cabmandone]

Originally Posted by Henry Schmidt

Head studs on air-cooled engines is about cylinder to head stability.
To build reliability and a stable platform for performance Supertec head studs offer the best all around clamping consistency that we've tested. We tested Raceware, ARP, Dilivar of every iterations and even a "Super Stud" sold as a Dilivar replacement by some of the wholesale outlets. The testing of course started with stock steel Porsche head stud and nothing even comes close to our design.
Add ease of assembly, unique design, unparallelled quality and a life time guarantee and Supertec stud heads are hard to beat.
And then there's the price that has remained consistent for 12 years.

Henry,
Maybe a dumb question but why doesn't anyone offer a stud with an 11mm thread on the bottom sized up from the 10x1.5 for guys like me who either had a messed up case or like me messed up one hole? I mean I'd have much rather had an up sized stud than a timesert or case saver put in. Is it because the mag cases would still have troubles with the new stud pulling out and not many of the aluminum cases later on had a need for inserts unless you messed up the threads?

[Jeff Alton]

Have not seen 12 broken ones, but we rebuilt a 3.0 earlier this year that had 11 broken ones...

[perelet]

Question is about relative thermal expansion of aluminum heads and studs. 964 had extreme all dilivsrs, 993 switched particular alloy steel for all studs:



Factory has so much variants of studs and surely bigger R&D resources than aftermarket companies offering studs that "work" for Shevy and 911 .