[Turbo_pro]

Originally Posted by Gunzel

I would like to ask a specific set of questions, with emphises on cost and end result.

1 In a Mag case 2.8 engine with Nikasil cylinders putting out 300 h/p which studs are recommended?

2 In an aluminum case 3.0, or 3.2 engine with Nikasil cylinders putting out 315 h/p which studs are recommend?

Please take cost into consideration, I have no need to brag how expensive my rebuild was, or that my studs will support the Titanic. I just want something that will not fail, and costs the least.


Mike

I've had 4 engines rebuilt within the last 9 years. Two mag case and two aluminum case engines. The first one was a 450hp turbo followed by a 2.5 SS, a twin plug MFI 3.2 and a 2.45 twin plug with 40 Webers making 180 RWHP. Three had Dilivar studs in them when disassembled. They were all built with Supertec studs and none show any signs of head to cylinder leaking that was present in my Dilivar engines.

Originally Posted by KTL

I think I can provide another example of Henry's experience with Dilivar studs. My '79's engine was built with all Dilivar studs. It exhibited the same condition that Henry's picture shows. Leakage above and below the cylinders.

Originally Posted by Weissach911

..........
I am quite sure your studs (Supertec) work reasonably well and have never criticised them and do understand the thinking behind the material selection .....................

Originally Posted by Steve@Rennsport

My heartfelt thanks to all the participants who have contributed their engineering and metallurgical expertise and hopefully made all of the readers a little smarter.

Posted by an engineer who offered us such a thorough analysis of the material properties and their function in this every changing environment.

Originally Posted by Weissach911

My conclusions in general are that I would tend to use standard steel studs in standard engines. I would be tempted to use Dilavar or A286 in Magnesium cases with Nikasil barrels and would use Supertec Studs in high performance motors.

Originally Posted by Henry Schmidt

The Supertec stud has far more than just a superior (debatable for sure) material.
The fine thread 12 point nut is a far superior design both in material and functionality. No designer of high performance hardware calls out coarse thread unless threading into soft material. Rarely/never with a nut.
The extra thread length for more thread engagement in the case. Thread engagement to resist pulling
Spark plug clearance for twin plug application. Barrel nuts used from 64-89 will interfere with the spark plug in an twin plug conversion.
Corrosion resistant material that will never break (any fair jurist will admit that even new Dilavar studs break) and the nuts will never seize on the stud (common with Dilavar)
No installed length issues that slow down assemble time. Ask engine builders if they ever had an issue with stud install height. With the install length issue resolved you can install the piston and cylinder without the studs in place making pin and clip installation far easier. Without the studs, you can install the piston in the cylinder on the bench and install the P&C as a unit.

During this discussion there was little or no mention or debate about the other features of the Supertec studs. Why is that?

Below are prices on some studs offered by our host.

Pelican Racing Head Stud Hardware Super Kit - 24 RaceWare Head Studs, 24 RaceWare Head Nuts, 24 RaceWare Head Washers $909.85 no guaranteeI stand corrected they also have a lifetime guarantee.

Dilavar Cylinder Head Stud (sold per each, 24 required), 911 Turbo (1976-89)
Brand: OEM $41.50 $996.00 without nuts & washers no guarantee

Supertec Performance Cylinder Head Stud Kit (sold as a complete set, hardware included), 24 studs, 24 washers, 24 flanged nuts $660.00 Life time guarantee