GregBBRD

Pick one or the other technique.. They both seem to work fine.

Chopperharris

Hi Greg


I'm about to embark on the reassembly of a 16v with new studs and head gasket. Have you found the current batch of studs from Porsche have the same characteristics as the ones you started the thread about? By that i mean are you still favouring both the 2x 90 degree angle or original torque methods for new studs?

Thanks
Ben

GregBBRD

I am not aware of a change in the head studs, in the past few years.

That being said, I have not tried 3x for several years, now....I got really tired of buying new sets of head studs (and head gaskets) to replace new, yielded, head studs.

Chopperharris

Thanks Greg - I’ll avoid the 3x 90 method and choose either of the other two methods.

Cheers
Ben

jpitman2

A bit off topic, but connected. Mate once worked on an oil rig in sea off SE Oz. It had a crane for lifting supplies and personnel off barges some 50M below. Every so often a maintenance man came on board and went around checking stuff. On the crane base he was observed to apply a very large wrench to the nuts (threads probably somewhere around 2" or more) and give them a pull. Mate, being somewhat mechanical, wondered about this as a bit incorrect. One day the crane was asked to lift a heavy load and the threads cried enough and let go, the whole structure went into the sea, complete with operator. He survived with minor injuries. Apparently the the threads went plastic due to over tightening, and were observed to look like they were still OK.
jp 83 Euro S AT 57k

Chopperharris

Wow - scary ****!

justaguy

I just came across this thread,very timely as I blew a head gasket on my race car due to stripped out threads in the block.( possibly over torqued, 4 X 90 by mistake) I had to install thread certs in the two center holes in the block.

Im just wondering what the consensus is on head bolt torquing on a 32 V engine these days. Sounds like 20Nm plus 3 X 90 then after a few hours back them off 90 degrees one at a time and go to 75 ft pounds.
Is that correct?

ptuomov

Suppose one were to order new bolts and studs from Porsche and do some destructive testing. How would you go about it? I like studs in principle, but material is also important.

GregBBRD

i'm aware of three different versions of 928 studs. Early "black" studs. 1985 vintage "gold" all thread studs. And the latest "gold" studs, which appear the same as the 1985 studs.

I'm betting that getting the metal analyzed from all three would tell volumes/would be super interesting and would be a great place to start.

I have samples of all three and could send them out. I also have ARP studs, which apparently (in my opinion), do not stretch enough at the given torque, which I could send, too.

worf928

Check with these guys:

https://www.nts.com/location/boxborough-ma/

2 thumbs-up from CarChick who used their services on many occasions.

ptuomov

Is the problem with insufficient (elastic) stretch that the setup becomes very sensitive to thermal expansion and fatigue of block and heads? How much tension can the block threads take? Are there other considerations, such as head warping, that prevent one from torquing that higher “spring rate” studs more for a greater clamping force?

Kevin in Atlanta

This by far is the best thread I've ever read on Rennlist.

I used it to torque down a set of S3 heads.

These were my steps.
Cleaned and chased the studs. All the plating was in good order.
Placed the the head gaskets and heads in place.
Roughed up the washers.
Marked them
Placed them on the studs and pointing the mark to 12 o'clock as you face the heads from either side
Used a QTip to lightly oil the top of the washer and the exposed threads
Loaded nut (all new) into a 19m socket on an extension
Lightly oiled the nut threads and exposed nut surface
Tilted the nut into place on the stud and hand tightened them
Then 15 ft lbs and 3 90 dg turns with my digital torque angle wrench
Came back and measured the resulting torque and all of them near 75 ft lbs and were within a couple of ft lbs of each other.

Very satisfying.