How to protect steel headstuds?

[andrew15]

If the head studs on my engine case are in decent shape, can I remove them, degrease, and put on a coat of epoxy to protect them going forward? I'm tearing the engine down for a rebuild and have to remove them for some spigot machining anyway. Regards, Andrew M

[cnavarro]

I personally would not coat them because it is possible that microscopic bits of moisture and other contaminants could get trapped by the coating and cause more problems than it would solve. The oxide forming on the outsides is a protective barrier, albeit an ugly one.

[rcwaldo]

Howabout zinc plating them?

[1972_911T]

If I remember rightly the cleaning process required to plate steel ie acid cleaning can lead to hydrogen enbritlement and thefore would not be a good idea on head studs.

Steve

[Jeff Alton]

Some of the new factory ones come painted.....

Cheers

[1972_911T]

Think its powder coated rather than painted, and thats mainly the delivar studs as they are prone to again hydrogen embrittlment. But if you did feel the need to have them coated I would think powder coating would be the best way to go as its applied with high heat therfore you have less risk of trapping water as it will be evaporated.

Steve

[kenikh]

I've read of a number of people zinc coating them with good results.

[andrew15]

Hmm - So degrease, beadblast, and then zinc coat with baking after?
I know I've seem some plated studs on previous threads, just not sure if they were new or replated
Regards,
Andrew M

[cnavarro]

If it were me, I would just buy new (and improved) studs before trying to do anything to a old and used stud. Plenty to choose from now a days!

[Jeff Alton]

The last 48 or so STEEL studs that I bought from Porsche were painted with a grey paint of some description. Not dilivar, steel........

Cheers

[cnavarro]

It's all in the prep before they get painted, black oxided, epoxied, etc, in a controlled manner. Very different from doing the same to a used stud. I spoke to ARP about this a few years back. Has to do something with a baking process before the exterior receives any treatment. Someone is welcome to correct me if I'm wrong, as I may just be full of it :-)

[1972_911T]

At the end of the day is it worth messing around trying to plate or paint old steel studs when there only like $9 each new. If you want painted studs buy the 993 style delivar they are black powder coated for about $20 each and not prone to breaking like the ones on the 3.2's. Think the plated ones you have mentioned others using will most probably be the likes of ARP and Raceware which have a shiny finnish but will set you back big buks and are not necessary on a stock rebuild. I just replaced all my head studs on my rebuilt 3.2 with stock steel ones as I have never heard of a stock steel breaking and there never seen when the engine ist together.

Steve

[cnavarro]

The ARP studs are raw/unplated custom age 625 whereas the racewares that I have seen come both in raw/black oxide coated. On the head studs that ARP makes for me for some of the other Nickies applications, they have done them for me both ways- ARP 2000 raw and/or black-oxide coated. I do think they look better when they are raw and polished like the 911 ARP's. I'll call ARP and ask them about painting or plating a used stud and see what they say, out of curiousity. I'll post the results of my conversation.

[cgarr]

Im not sure why they really snap but if you look at them close you can see that the studs are turned down on a lathe, you can see and feel where the tool cut the stud, this cant be good for Relieving stress

[911pcars]

Are we looking for a solution to a non-issue? A lot of you guys have more experience in this area - is there a history of steel (not Dilavar) studs breaking? I'm thinking the tensile strength of steel CH studs far exceeds the load in this area.

MHO,
Sherwood

[Henry Schmidt]

In 27 years of Porsche engine building I have yet to see a steel stud break.
I have seen a million broken Dilivar studs but not even one broken steel stud.
It's such a non issue that Supertec head studs are non coated and carry a life time warranty.

[911SCfanatic]

I have a feeling I'm going to regret this...but why do people buy Raceware, ARP, Supertec or any other stud than the OEM steel studs? I assume breaking studs isn't the only issue otherwise partially threaded 993 studs would work for all applications--mag or aluminum. Do you have to use something better than the OEM steel studs once you go above a certain h.p.?

[Henry Schmidt]

I'm not certain why people buy ARP or Raceware head studs. The reason to buy Supertec head studs is because the design is better than any other stud on the market.
Not only is the material better but by using both coarse threads and fine threads on the same stud we take advantage of the principles utilized by Cosworth, Rolls Royce, Continental Aircraft engines and every F1 team for the last twenty years as well as Hewland the quintessential transmission builder on the planet.
The material offers head support that prevents separation of the head from the cylinder.
One of the things we discovered during years of race engine building is that stock steel head studs, Dilivar and Raceware head studs all allow the head to lift limiting the amount of cylinder pressure that the engine can handle.
This directly effects the efficiency of the engine.
BTW:
Recently ( about 2 years ago) I asked ARP to manufacture my studs and they declined and the result was ARP now makes a stud of remarkably similar material to mine. Wow imagine that.

[ischmitz]

Henry,

What is the advantage of the finer thread pitch for the nut?

What is the primary reason your studs do not allow the heads to lift? The different thread pitch, or the tensile strength of the material used or something else? Just curious,

Ingo

[paulweir]

I too have never seen a broken steel 911 headstud. You don't have to do anything to them what so ever.

15 years ago when I built my early style 370hp 3.5 RSR slide throttle engine I used Raceware studs, nuts and washers because they are made out of better material and I wanted to rev my engine to 9200 rpm and wanted the engine to be as bullet proof as possible. And it has been for the last 15 years.