[reclino]

As a mechanical engineer and first time engine builder it has been frustrating to navigate some parts of the build process. Its clear that steel studs work in this application, and early in my build process 4 years ago I was advised by Chris Flavell that steel Studs from Porsche were a cheaper option that would work fine for a stock 930 rebuild. So I bought a set from Porsche. As my build goals warmed up a bit,.with bigger intercooler and free flow exhaust / headers I had the funds available to purchase the Supertec head stud kit. Peter Dawe recommended them as more affordable than the 993 studs.
Neither of these purchases were based on what I would call data. These are parts that have been proven to work in service. I am not sure how anyone other than OEM could do an engineering evaluation of this type of assembly. The joint gets tighter everytime you start the engine. An ideal joint would have a clamping set on assembly.by stretch or torque, and the tension in the fastener would not change in service. It seems like this head stud can change tension due to thermal loads, and possibly engine loads, this is a very complex situation to analyze.
I worked on a National Science Foundation project studying coefficient of thermal expansion of some low expansion materials, Invar being one of them. The time and effort to actually get valid data on that project was mind blowing.
At my current job we did some repairs to a high pressure high temp piping system, 800 psi and up to 1400 deg F service temp. How do we test the repair to be sure it's safe to operate the system? The last section of the high pressure pipe code I read through said if there are no other possible ways to test the system then an in-service test is acceptable. In service test means clear the area of people, turn on the system and ramp up to full pressure and temp and see if it fails. Slightly scarey when it's a 3 million dollar system of inconel pipe your testing.

So to sum up, I am really growing tired of each camp screaming louder and louder that they are right and everyone else is wrong.
To those people screaming the loudest, sit the **** down and chill out. Listen to what other people are saying, then bring some data to the table to move this conversation forward.
I would like to continue to learn about this complex puzzle called an engine that's laying on my work bench.