I disagree with the economics. Porsche had a solution to the broken dilavars by switching to steel. They then switched back to dilavar. The dilavar studs cost more than steel.

The costs are not in the manufacturing as much as in the warranty costs and brand damage. In essence, spend a little up front to avoid unhappy customers during the warranty period.
Engineers design with criteria that is sometimes obscured from the consumer. Mass production comprises we'll call them.
The plan behind using Dilavar in a production motor was an attempt to control seepage from the heads on cool down. It had very little to do with seating pressures at operating temperature.
The engines of the time were designed with thermal reactors and they created a serious dimension problem after the engines were shut off. These 1800 degree cans located directly below aluminum cylinders were rediculous. Ever wonder why the SC only had lower Dilavar studs?
The issue was studs pulling from stresses after shut down. I was working at the dealer during this nightmare and we were repairing engines left and right under factory warranty. Most were for oil leaks and head seepage. Not to mention tensioner collapse.
This high temp cool down (the engines actually got hotter when first shut down) was a real warranty issue.
Dilavar was installed to deal with high heat from smog equipment not as a performance enhancing revelation.
The turbos exhibited the biggest problems so in an attempt to deal with this issue Porsche, in it's ultimate wisdom started to whack fins off the turbo cylinders. This was an attempt to control expansion issues at cool down even though the engines were equipt with Dilavar. We in the private sector figured out the problem. Too much heat. Porsche was stuck with thermal reactors and we were not.
How many of you are willing to whack cooling fins off your cylinders so that your engine won't seep on cool down.
I for one was not. We controlled the temperature by removing smog equiptment, improving coolers and registering the cars out of state. Porsche stuck with the half finned cylinders as a compromise in order to sell a smog legal car. Don't believe for a moment that half finned cylinders was not a compromise. They comtinued this compromise far beyon the thermal reactor was removed. One of the cool things about building custom engine for specific users is that we get to eliminate some of the production compromises that mass production demands.
When Porsche discovered the breaking issues with Dilavar they painted them. Throughout this breaking stud period Porsche tried different sealing techniques to little or no avail. They tried to remedy the issue with a ce ring, no gasket, an asbestos gasket and then a sealing ring and then replaced the studs with steel only to find that the old design steel stud was perpetuating a warranty issue again. . Knowing that the air cooled engine was coming to the end, Porsche went back to what they remembered. This time they addressed the breaking issue by adding material. Still a compromise but that's what production lines must do to survive.

BTW: This is from memory. I lived it, I didn't read about it in a book.

So on a Carrera or SC (neither of which had thermal reactors AFAIK) using all steel studs will result in head seepage?
I'm especially interested because I'm about to rebuild my SC engine due to a busted head stud.

Using stock steel head studs on an SC engine will generally result in seepage.
Heat will be an issue as will your right foot. The harder you drive it the more likely it will seepage.

We just took this 2.7 MFI engine apart on Tuesday. Car was driven hard.
All head nuts were torqued properly.
Note the seepage.
No CaseSavers were pulling.
Note the head movement.
Note the stud we removed.
This engine had 17,000 miles on an OK rebuild.


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I don't know enough to judge from those pictures so I'll take your word for it. According to Wayne's rebuild book steel is fine for a non-race engine, glad I asked. Thanks.

Steel studs work ok on my 3.0 race motor and were free (used ones from my machinist). They did need to be retorqued after a couple of races because some of them became loose. They have stayed tight now for 2 seasons, but I check them every year when I check the valves. They don't work as well as the two expensive options discussed here but I'd rather save the money.

-Andy

Great explanation Henry!

I for one am please that people like Henry, Chuck Moreland and Steve Wong, not to mention Wevo, Rennshift, Seine Systems, etc, etc are developing new and improved products for our cars. Without this innovation, we'd all have a less fun environment to play in.

Henry, do you think that the pictures of the 2.7 you showed us above would have been different if the car was for street and not driven as hard? (Or was that a badly beaten street car??).

88 Diamond Blue and ixOifan,

I spoke to Neil @ Performance Developments and asked him many of the questions raised here. Got some really interesting information. I will PM his answers to you both offline. Not trying to stop the flow of information and resources, but I too believe its time to go.

Many had PM'ed or emailed me for a copy of Neil's (PD) opinion of Head studs. I replied to all I think, but in case I have overlooked someone, please PM me or email your address and I will forward.

Sorry for the delay. He had sent me something sometime ago, but then sent a more in depth opinion today.

Simon

Why not just post it here?

Lindy

Have you ever heard of the term; "Perfect Storm"? ;)

If I forgot someone who had requested the document, please email me again. I sent out approx 100 and may have missed someone by accident.

Simon

I'll be using these!! :D:D:D
Thanks Henry!


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Im jealous! I really need to buy a set!

My friend mechanic was impressed by them.
He also had the impression they were light compared to OEM studs. (which in my book is a good thing, adding lightness!)

Am resurrecting this ol' thread to put Henry on the spot since... he seems to be the only stud-man that's put his money where his mouth is. If I'm wrong about this, apologies in advance. Also, I read through a good bit of the thread but not the whole so might be more to piss on me for but here goes.

Supertec offers a lifetime guarantee. Bold move for sure. But then disclaimers can easily lube a guarantee to the point where it's so slippery there's no holding on to it when push comes to shove. In the case of Supertec, I know the guarantee mentions an inspection of the engine which makes perfect sense...

Henry... if you're still around, would you speak more about the guarantee. The purpose being to squelch any notion of the marketing department running the show as opposed to Supertec's studs actually being a superb product capable of standing up to the lifetime guarantee.

I can pretty much state the "marketing dept" doesn't run the show at Supertec. Consider me one satisfied customer. Although I don't have the car/engine any more.

+1...been in an engine for 8+ yrs w/o any issue...
maybe is someone having a slow day at the office & needs to micro the micro of he micro of the micro, ~ infnity...???...)))

My studs are the best I could build. They are guaranteed for life. There is no situation that limits that warranty. We have never denied a claim. Both claims made over the years were damage caused by the installer and we replaced them anyway. We have even replaced lost parts for free. These are the last studs you'll ever need to buy.

Thanks for reply Henry. Am going to delve into finer details here to confirm for myself---and perhaps others---that Supertec is the best path to take for studs.

Should engine inspection be called for, exactly how would that procedure occur? ...Does owner have to ship engine to you? You come to engine? I ask because you're in Fallbrook, CA (beautiful location) and I in Miami FL. Obviously shipping an engine back & fourth is consequential for someone.

Also, is there any compensation offered to an owner (for mechanical service costs) after studs are replaced if snap occurs within x miles?

Important to note that I'm not dooms'daying here. My intention is to understand the implications of your guarantee given the distance between us. I've read a good deal about various stud types and Supertec's---with your backing as noted---appears the clear winner from my perspective.

What is it that your looking for here. I don't know Henry, but he's a stand up guy from what I have read here and in other places. When I need studs they will be Supertec. What your digging for won't be found, so just stop....please. Why not take it offline and speak directly to Henry?

^^No kidding. Henry has been around here a long time, offered a lot of advice, sold a lot of parts to home builders. He's also built more than a few engines in his career.

Seems like one may stand to gain more from their time doing things like worrying about what may happen to them before they pull out of their driveway and enter public roadways.

Jon... If someone is willing to back up their product like Henry, I suggest that's clearly more admirable than any other company not willing to do so. And Henry is doing so = ADMIRABLE on his part. I'm asking a legitimate question about how Supertec's guarantee works.

I appreciate you're input in regards to what I'm asking for "not being found"... with all due respect, Henry should respond or not. In the least, he's the one to say "I prefer not to discuss the details of my guarantee any further than I already have" and so be it.

I've experienced guarantees that are next to meaningless once a problem is experienced. Perhaps you have not. And so my interest in where Henry / Supertec stands in regard to the details.

More...

Everything I have heard about Supertec's product is second to none. If I'm going to choose a Supertec product over any other, I'd like to know as much about it as is possible. Surly others hold the same. Again, if Henry wants or does not want to talk about the details of his guarantee... his choice. As far as I'm concerned, there was and remains no reason for a dialogue with Henry concerning Supertec's guarantee to be hidden via PM.

I'm Quoting from memory so I could be wrong. I looked into Henry's headstuds a few years ago. I think they're a type of stainless steel an as such have a coefficient of expansion closer to aluminum than plain steel studs. That and the fine threads with good nuts makes these a fine choice.

-Andy

Unless things have changed they are 17/4 PH which is a Martensitic Precipitation Hardening Stainless Steel which has roughly the same CoE as a conventional steel.

It is the Austenitic Stainless Steels that have the higher CoE - such as Dilavar.

Here is the instruction sheet that comes with every head stud kit.
The warranty is clearly stated in .
Cheers



SUPERTEC PERFORMANCE HEAD STUDS KIT

INSTALLATION INSTRUCTION
1) USE BLUE LOCTITE ON CASE END (10 x 1.50)

2) USE SUPERTEC THREAD LUBE OR ANTI SEIZE ON CYLINDER HEAD END

3) CLEAN CASE THREADS COMPLETELY
We recommend a thread forming tap (1.50x10 PD-6 6-N) for this application
The stud should show little or no resistance, DON’T FORCE THEM

4) TO INSTALL STUDS, DOUBLE NUT WITH THE NUTS PROVIDED

5) INSTALL STUD UNTIL IT BOTTOMS AND TURN OUT 1/4 TURN

6) INSTALLATION LENGTH IS NO LONGER RELIVANT

TORQUE SPECIFICATION + or – 2lbs STANDARD TORQUE PATTERN IS MAINTAINED
a) 2.0 aluminum case 30 lb/ft
b) 2.0, 2.2, 2.4, 2.7 ( all magnesium cases ) 26 lb/ft
c) 3.0, 3.2, 3.6 aluminum case 30 lb/ft
d) 3.0, 3.3, 3.6 aluminum Turbo 32-36 lb/ft
THERE IS NO RETORQUING NECESSARY

Supertec Performance guarantees these head studs against BREAKAGE forever.
If for any reason [short of intentional destruction] this stud breaks, Supertec will replace it.
We only warranty the part. No incidental damage or labor is covered.


Supertec Performance
445 Golden Road, Fallbrook, CA, 92028
Ph: 760-728-3062 fax: 760-728-3063
Email: supertec1@earthlink.net
Supertec Porsche Engine Rebuilder