Cool to see an Audi guy here. I've used MLS head gaskets & ARP studs on all my big turbo Audi builds with no issues too.
Love the S7 too, will seek a '14 S8 or RS7 in 15years when I may be able to afford them

 

I have to agree with MasterTech on the stretch bolts. ARP studs are awesome for use on cast iron blocks and beefy engine/head combos running turbos and blowers, but using torque-to-yield bolts provides a more uniform and forgiving clamping pressure. By elongating the bolts you put tension into the system, essentially loading a spring. This provides clamping pressure as a function of the properties of the steel rather than some torque developed on threads that may be affected by friction at the nut to thread interface, or nut to washer or washer to head. The modulus of elasticity of steel is a fixed number so the clamping pressure delivered with a yield type bolt is very consistent. There's a reason modern engines use these bolts.


As for the quality of the LR head gaskets, I agree that 70k "lifespan" is BS, but getting another 70 or 90k out of the engine after a weekend of work isn't a bad deal. Don't forget, if it wasn't for the head gasket and other known LR issues, these things wouldn't be affordable for us 2nd (or 5th) owners. A Toyota Land Cruiser with 100k on the it is worth $23,000 while a Discovery 2 is worth maybe 1/3 of that. All that leftover money buys lots of parts.

 

but if you watch any new manufacturing process using STY they also have one impact that torques all bolts at the same time. (ok millisecond apart).

 

Can you just retorque the studs

 

He posted that they were rechecked but he certainly could, although that will likely cause his one dry spot (the VC gaskets) to start leaking.

 

now, I am curious as to the torque specs. few different suggested, what did you go with?

 

These were my first thoughts, also.

I'm a strong supporter of RTV on most gaskets. Hell, I've used RTV instead of gaskets on a few occasions.

 

Definitely something I wondered about for ARP studs as well. The head bolt torque specs for this motor are all preliminary values from which to start the stretching of the TTY bolts so you would need to make up your own values for studs unless ARP has some guidelines.

 

Arp had some guidelines and then retracted the numbers as the final value was snappingly too high. No real baseline exists. I did my own based on absolutely nothing. I think I through my college jersey number in there.

 

ARP and STY bolts have completely different toque values. ARP actually gives you a final torque spec, of like 60-80 psi in three steps.