Porschefile

Cool! Thanks for being the guinea pig. I didn't realize you were on stuck head studs. ARP does make great stuff, and their products have been pretty widely proven in a huge variety of motors. I guess the real question though is how much of an improvement are they over stock. ARP lists all the info you could possibly want to know on their website, regarding the metallurgic properties and various alloys used for their products. Does anyone know anything about the stock studs as far as the specific type of alloy? From what I've seen in the past, I'd tend to believe that ARP's alloys are probably superior to the oem stud's.

Oh God, considering I can remember Stretch Armstrong, am I just too young?

Porsche-O-Phile

Wow. . . "Stretch Armstrong". LOL!

I actually remember that. I guess I'm an old fart.

toddk911

Just like drag cars

toddk911

So is the issue, as someone said, that this turbo just makes more boost sooner so the head had more pressue sooner???

Could you try a run with a boost setting for higher rpms to see if that helps? So with EBC have boost not go to 28psi unitl 5K or something along those lines.

kasturbo

Is there an advantage going with the ARP's over the Raceware studs? Do both require you to retourqe after so many miles?

xsboost90

some old porsche race cars had the heads welded on- not sure which ones though.

hot-J

How many times did you reuse the porsche studs?

special tool

the old turbo did the same thing - its on my old dyno video.
The lift is worse at high revs.

special tool

4.

And be advised...
my engine was good up to about 500 hp with these old studs - but no more.

Tom M'Guinn

Good move. I torque to 85 - 90 ft lbs, per Gomes. Gomes has been there and has the t-shirt.

toddk911

Once the head lifting issue is resolved, what would be the next weak link that could show itself???

Mark-87-951

That's a good question. I certainly hope it isnt something more catastrophic.

Good luck! this has been very informative.

special tool

yes, but no dyno evidence past 500 RW.

Laust Pedersen

The vintage Bugatti had the block and head cast in one, so no messing with headgaskets, studs, nuts and assembly torque.

The MLS HG is much stiffer than the WFHG, meaning that head-gasket-block separation requires less stretching of the studs and therefore less force (combustion pressure) for the same clamping force (head nut torque).
As Tom was suggesting, I would try to get some information on max allowable head torque and target that. As I recall, I am at about 90 ft-lb with MLS and OEM studs.

Laust

toddk911

Kind of scary though as this route is like a pressure cooker with NO release valve!!! I think they also call that a grenade