Headstuds - would you use these?

[m42racer]

ixOifan,

Pretty sure you have gone over the top of most heads here.

I think all of the studs offered to the aftermarket are good and very similar in quality,including the Supertech ones. These would include ARP, Raceware, A1 Technologies and the Porsche OEM. The missing brand is the Performance Development studs.

They used to make studs for many years before ARP and Supertech were around. Raceware were making studs back then. PD stopped making them as the newer Porsche OEM types are a good stud. Prior to these newer OEM studs, the Porsche Divilar types were prone to fail, so PD made a stud as an alternative. Cannot tell you what material they were made from as I do not have this info, but I do know it was special. There were never any issues with these studs.

I have been told that the reason heads come loose is never because any of these aftermarket studs fail. I am sure there are many engines out there that have Raceware, ARP, Supertech, etc and never had any failures. In most cases I'm told failures occur due to other reasons. Poor quality threads in the case often caused by studs been installed all the way to the bottom then tightened. All this does is stretch the threads in the case and weaken them. Or the heads collapse around the stud due to a softening of the head material from use, or from overtightening of the nut. Always user caused. Most of the time the builder will always blame the stud, never what they failed to address.

It was found that when all of these factors were addressed, the new OEM stud worked very well. I asked Neil once why they stopped and his reply was " if I wanted to make something just to put my name on it to sell, I'd go into the T shirt business".

If there is no engineering advantage, why do it? I suppose one could argue that Raceware and ARP are in the fastener business, so it make some business sense to make an alternative. But an engine builder doing this just to do it, make sense only if you want to sell something. It's apparent then that PD stopped making the aircooled studs because the OEM stud did it's job and well.

I think you are correct about staying with the OEM stud. As it has been suggested in other posts, some really well respected engine builders use the new OEM stud without any issues.

If you have any doubts about what stud to use, I'd stick to the OEM stud and look at the other factors. Case threads, Washer platforms in the head etc., before spending any money on any stud. After you have these all sorted, make up your mind based upon good engineering judgement, nothing else.

Call Steve @ Rennsport, Neil @ PD, ARP and get their opinions. At least you can speak to people who understand engineering and who are engineers.

Good luck, but reading your posts gives me reason to think you have this all figured out already.

[Henry Schmidt]

Originally Posted by m42racer

ixOifan,

Pretty sure you have gone over the top of most heads here.

This statement seems to talk down to the potential reader. Seems a touch condescending. I guess I'm not the only one guilty of such transgressions.

Originally Posted by m42racer

If there is no engineering advantage, why do it? I suppose one could argue that Raceware and ARP are in the fastener business, so it make some business sense to make an alternative. But an engine builder doing this just to do it, make sense only if you want to sell something {edit}or that he determines that the available products are not good enough for his efforts.

Call your experts and ask if any of this is false.



The potential benefits of fine threads are:

1. Size for size a fine thread is stronger than a coarse thread . This is both in tension (because of the larger stress area) and shear (because of their larger minor diameter).

2. Fine threads have less tendency to loosen since the thread incline is smaller and hence so is the off torque.

3. Because of the smaller pitch they allow finer adjustments in applications that need such a feature.

4. Fine threads can be more easily tapped into hard materials and thin walled tubes.

5. Fine threads require less torque to develop equivalent bolt preloads.

On the negative side:

1. Fine threads are more susceptible to galling than coarse threads.

2. They need longer thread engagements and are more prone to damage and thread fouling.

3. They are also less suitable for high speed assembly since they are more likely to seize when being tightened.

It seems all the negatives deal with assembly error. Our design addresses thread galling issues with dissimilar materials and anti seize.

Potential benefits of the 12 point nuts.

1) Quality of material 12.9 fine thread

2) Ease of assembly, standard 12 point socket

3) no need to measure stud install height

4) spark plug clearance for twin plug application

5) will never seize on stud from corrosion

On the negative side

1) can't use your cool allen wrench

2) Need to make new cylinder holders for assembly.

Forgot one more thing, the nuts are manufactured for Porsche and carry a Porsche part number.

BTW: m42racer Thank you for allowing me to list the engineering advantages of Supertec studs. It's not advertising if you're just answering a question. Any more questions.

[kenikh]

To summarize this WHOLE thread:

Old Dilavar studs suck
Stock steel studs suck for anything bigger than 2.4L
Fully threaded 993TT studs work awesome, but can still corrode
ARP studs seem fine, but...
Supertec studs have taken the lessons above and applied learnings from them all with diligence and care.

I've said it before: I took every detail in this thread, many even before the were written, and chose the Supertec studs. 993TT were a VERY, VERY close second - price was the tie breaker.
If you've ever held a set, you'd understand.

I may sound like a "honk", but b#!!$hit walks...I work with guys I trust. Cross me once and I am done. Every penny I have spent with Henry has been unregretably spent. Same goes for Steve Weiner.

[88-diamondblue]

I rebuilt my 88 Carrera due to two broken Dilivar studs with 88,000 miles. These studs were the coated studs to prevent corrosion which didn't stop the studs from breaking. Dilivar studs will break. Carrera's are getting to be old enough to repeat the same thing with studs that SC have been happening for some time. This will continue as dilivar ages.

Using an after market product make a lot of sense as well as being less expensive to buy than replacing the stud with Porsche replacements as that would cost $740 for using 12 dilivar and 12 steel with washers/nuts and over $1000 for all dilivar. I have read the threads over the last 7 years and have seen many threads about broken studs. DILIVAR FAILS! Just a matter of time.

The engine builders that post here are a great resource for all of us here. Of course each of them have their way of doing things and what they have found to work. How many of us here have rebuilt hundreds of engine to know what works? As Aaron stated that heads move when using dilivar. Pretty hard to argue with this as more than one engine builder is seeing this happening. And I have read threads about the ARP nuts coming off. Might be an installation problem but the ones that I saw were sure they were torqued properly.

When I did my engine I used steel all the way around. Had this been for racing or higher compression I would have used the Supertec studs as IMHO are superior to the other available options. As Aaron said, Porsche thought going to a smaller rod bolt was fine too. Not so much. There have been many examples of failures from the rod bolt stretching. Mine has ARP. There are products that are better than what Porsche designed, head studs and rod bolts are just a couple of them. As far as promoting products here I have no problem with it as Wayne doesn't seem to have a problem as they sell the product.

m42racer
I would like to know more about heads softening. I have not seen any reference to
this before.

+1 on what Aaron said that this subject There is too much "mental masterbation" over this subject. Use what you are comfortable with. There is more than enough info to make a decision...

[Henry Schmidt]

For those of you with sensitivity towards passionate retort please skip this post.
V
V
V
V
V
V
More than once on this and other threads I have been accused of touting my products for profit.
Just to be clear, I make 10 sets of studs every quarter (making me the smallest player in the market) most of which we use . I could and do make more money playing poker than I do selling studs. I make them because I don't feel that any other stud on the market is good enough for my motors.

Some people put their name on tee shirts. I put my name on every motor Supertec builds and behind every post I make. Our motors may not be the best product on the market but they are the best we can build. I use our studs because I believe they help us to build the best engine we can. I'm on this board to help you DIYers do the same.

If bragging about my products seems somewhat crass, oh well. I've been called worse.
There is an ignore button that allows you to skip my posts, if you are truly offended please use this option.
Cheers

[MarKoBrow]

You make the studs or do you have them made? I don't care either way but if you have a thread rolling machine why not make rod bolts and other fasteners? I still want to know if the original poster was helped throughout this bloated thread?

[ix0ifan]

Having followed this and many other threads which try to deal with what seem to be serious issues I think its time to go.

[Henry Schmidt]

Originally Posted by MarKoBrow

You make the studs or do you have them made? I don't care either way but if you have a thread rolling machine why not make rod bolts and other fasteners? I still want to know if the original poster was helped throughout this bloated thread?

We have the studs made to our specifications by a company that makes studs for other Porsche stud suppliers. They actually market their own stud and find my design and material superior to theirs but too expensive to make a profit manufacturing.
They also feel that Porsche owners are finicky about new designs so they thought a conventional looking stud was easier to market. Their words not mine.
We don't make rod bolts because we believe that ARP got it right with their rod bolts.

[Carrerax]

Originally Posted by Steve@Rennsport

They are not the same. The 993TT, 3.8RS and RSR all use a different stud and those are ones we use in all 3.0 or larger engines.

When Steve @ Rennsport talks....I listen. That is all I needed to hear on this subject.

[Henry Schmidt]

Originally Posted by Carrerax

When Steve @ Rennsport talks....I listen. That is all I needed to hear on this subject.

Einstein wrote, "Blind respect for authority is the greatest enemy of truth."

[Carrerax]

Henry, I have worked with Steve on several Porsche projects from my 993 to my current 3.2ss. I dont have blind respect. He has fully earned the respect that I have given him and his company. After spending several hours in several different instances talking to him (as well as spending thousands and thousands of hard earned dollars) and analyzing his advice, I choose to take his opinions and advice with authority. I have never heard him say derogatory things about his competition or talk down to me or others. This does not mean your advice etc isn't appreciated because it is. I just dont appreciate your superiority complex over others in your field. You may be the best in the business and quite frankly I haven't heard anything negative about you or Supertec. I am sure that you didnt get to where you are by not being very good. In fact it is probably to the contrary. It just seems that you like to get people worked up. That is all well and good sometimes. In fact, I do the same from time to time. You would probably be fun to go have a beer with but it just seems a bit childish here. Just my opinion. Im out.

[Cupcar]

I've used both Supertec and the late 993 Dilavar studs and I like both.

Personally, if there is no corrosion on those Dilavar studs I would use 'em.

[Henry Schmidt]

Carrerax let's evaluate your last post.
You don't want to hold hands, walk on the beach and you're not going to vote for me as prom king. You can't believe how sad that makes me.
I'm not here to be popular. If you don't like my style don't read my posts.
First, I have never said anything bad about Steve or anyone else who didn't attack me first.

Let's evaluate Steve's statements.

Originally Posted by Flieger View

I will admit there are better studs, though.

Steve's response
Not really,....
This is in fact him (Steve) saying, no stud is better.

Next we see this

"To be fair, we've not used the Supertech head studs as of yet simply due to our successes with the late 993TT studs (same as RSR/GT-2)."

I wonder if we would have a 4 valve head if Cosworth would have taken that same stance. "two valve heads have been so successful why would we try 4 valves".

Next we see :
"R&D and new product evaluations are normally done on our own personal equipment or when a customer consents to being the "guinea pig" in such rare circumstances."

None of this is wrong, it just shows a mindset. We were willing to identify a problem, step out of the box and try something new. Strangely enough not one person who has actually used our studs has ever reported to me that they had a problem. All of the critiques comes from people with ZERO experience with my product, stating someone else's experience. That is blind ....edit....respect for authority. "Porsche did it so it must be good", "we never used those but these are better because we have used them successfully". The logic escapes me.

I get it. Some of you don't like my style. I don't care. Just try your best to set personalities aside and reason through the information.

[WERK I]

Steve @ Rennsport has my full support and I suggest any of you out there who have received his unselfish support for years, do so in thread as well.

"Blind authority"? Enough is enough.

[Henry Schmidt]

Originally Posted by WERK-I

Steve @ Rennsport has my full support and I suggest any of you out there who have received his unselfish support for years, do so in thread as well.

"Blind authority"? Enough is enough.

Don't be an idiot.
I didn't mean to say "Blind authority". I meant "blind respect for authority".'
All that means is you should open your eyes and see what is right in front of you.
Steve is a great asset to this board and an honest agent. He stated what he honestly believes and then added a caveat.
All I did was ask you to read what he said and don't ignore his caveat.

Opps I just reread my post and I was wrong. I meant to say "blind repect for authority".

[K24madness]

Such a passionate topic.

We all know porsche used dilavar, had problems and switched to steel. They then started reusing dilavar again. One has to ask why? Economics? Doubt it. Why switch back to something that caused so many problem after finding a solution for it? What do the smarty pants engineers at porsche know that we don't?

[88-diamondblue]

Porsche only has to design something to make it through warranty. Of course we know that dilavar has lasted much longer than that but they have continued to try and make different versions of these studs to get it to work. The newest threaded version has not been out enough to know if they solved the issue. From some reports they have broken before the engine was ever started. There is enough information to know that dilivar breaks and is not just SC's that have broken dilavar studs.

After reading just about the entire engine rebuild section before I decided on what I was going to do on my rebuild, factoring the budget, that I was not going to use Dilavar. This subject has come up numerous times and every one can use what ever they want. If you think Porsche had the best product use it, you or someone else gets to fix it again as the odds of failure are good, historically speaking. Others will use a superior product or even Porsches own steel studs of which there have been no failures that I have seen or John Walker has stated that he has not seen them fail.

I have taken advice from the posts of Henry. Steve, Aaron and John W as they are of great value to this forum and all contributed to my engine rebuild. Someone here tell me which of you that have more hands on engine rebuilding experience to judge what studs work and what doesn't. I do not blindly following Porsche as having the best engineering with everything, they don't and has been proved many times as each series of cars has their own issues. There are after market solutions that are better than the original for these issues and maybe Porsche's last try at dilivar will last.

I didn't see any post as an attack on anyone. If Steve feels slighted by this (doubt that he was) I do believe that he can fend for himself. Henry is who he is Like it or not. I have done business with Henry and received great information on what I advice I was asking for. Everyone makes a decision of what head stud to use and what mechanic to put their faith in for advice. Your choice your money!

[jjrowe]

When was the last time Porsche did any engineering on air cooled head studs? Is it not possible that with today's technology and historical data that Porsche would have used a different design if they had to make these again? It seems like Henry is just modernizing an old design, not really competing with Porsche engineers because they were done with these a long time ago. Makes sense to me.

[K24madness]

Originally Posted by jjrowe

When was the last time Porsche did any engineering on air cooled head studs? Is it not possible that with today's technology and historical data that Porsche would have used a different design if they had to make these again? It seems like Henry is just modernizing an old design, not really competing with Porsche engineers because they were done with these a long time ago. Makes sense to me.

No question about better resources today. Look at the CAD modeling available to the laymen. I think windows 3.1 was the standard PC OS when the latest 911 (993) was designed.

No doubt Henry's approach of threading the stud deeper and using fine threads on the nuts is better than stock. Its the mystery of material choice that has me wondering what Porsche engineers know that we don't. To start with dilavar then go to steel to solve the breakage problem then switch back to dilavar.

Porsche has made some mistakes in the past. Most were based on sound engineering principals. The problems were mostly related to poor materials. 9mm rods bolts and dilavar stubs are one such example in my opinion.

[jjrowe]

We all know porsche used dilavar, had problems and switched to steel. They then started reusing dilavar again. One has to ask why? Economics? Doubt it. Why switch back to something that caused so many problem after finding a solution for it? What do the smarty pants engineers at porsche know that we don't?

I would guess that economics played a large part in it. The air cooled motors were on the way out, they had experience with Dilavar and steel and there were advantages/disadvantages to both. Starting over with an entirely new metallurgy would have meant lots of time and money whereas just updating an existing design would be less expensive.

We all agree that the Porsche body of work is impressive but there will always been room for improvement for those willing to spend the time and money to find it.