Engine Stud Nuts And Washers
 

I noticed on my engine (and the parts view) there are no washers under the nuts that retain the heads. Yet, the Supertec, ARP, and Raceware sets all come with nice CNC/hardened washers. Anyone know why? It seems this would affect the torque values...

Also, one of the manufacturers, Raceware, claims up to 15 degree cooler engine temperatures with their 12-point aircraft nuts. How is this possible? If the nuts have no cooling fins on them how can they dissipate any more heat than stock nuts?

Curious,
Mark

No head nut washers.
http://forums.pelicanparts.com/uploa...1221858211.jpg

Mark,

964 and 993 engines use a different head nut that incorporates a "washer" into the design. Earlier engines used a separate washer, similar to the ones offered by the aftermarket head stud manufacturers.

I won't comment on Raceware's absurd claims about such a product reducing engine temperatures,...............

It appears the 964 and 993 engines do not use washers below the head nuts. I would recommend moly be applied to the mating surfaces to insure accurate torque readings.

Oh yes, and probably a 10% reduction in Global Warming too! :D

I'm not trying to hijack but why the change in style?
Would there be any issues/advantage in using the later style head nuts on an early head?

I see they use a 12 point instead of a hex

-Ernie

I usually use the late ones, anymore. :) :)

Thanks Steve.
Cost-wise it looks close to "a-horse-a-piece" with the older style nuts and washers.

-Ernie

Ernie,
The nuts are actually removed with an XZN M12 (triple square) internal wrench of the German variety. I have the Dilavar studs and although I had a lot of creaking during the removal of each one, none of the studs broke and none were found broken during disassembly.

Porsche must have had a reason to go with the combination nuts with the incorporated washer. The Bentley manual suggests an initial torque of 11 ft-lbs followed by a torque angle of 90 degrees. I will use Opti-moly HT grease on the threads and bottom of the nuts.

Thanks,
Mark

Mark, thanks for the info and the specs! I just happen to have the triple square.
It is good to hear more tales of the 993TT studs in play without incident.
I know that "creaking" sound from the removal of the steel studs on my mag case...Very unnerving but after the first few I started breathing again!

-Ernie