was Re: Weepy Head Gskt Fix!is stretch bolt defence clamping methods,

[Avi <Avi@cosmoslink.net>]

Mik,
stretch bolts are used in HEAVY DUTY engines the ones that cost $500,000
(and more) AN ENGINE.........including some small ships engines........the
stretch bolts are installed with an hydraulic set-up...(and they get reused).
(in essence all threaded fasteners are a VARIATION of so called "stretch
bolts" including your "Raceware"), the difference in your OEM "stretch
bolts" is that the bolt is taken a lot closer to the yield point, in other
words using it to the MAX, that is also the reason why they are not
recommanded for REUSE, since they (the bolts) might be too close to the
yield point (after the first use), BTW, you can reuse OEM stretch bolts but
you MUST measure the bolt to find out if it did not exceed the yield point.

"The highest possible clamping forces with very small variations can be
achieved with threaded fasteners using the angular tightening method and
the yield point controlled tightening method" (from automotive engineering
handbook).

Avi
one of this days you might tell me how you can pull a head STRAIGHT-UP from
a VW 4cyl without taking the "studs" off......(engine in car...)


>As for the "stretch-bolts" being "BEST" there more in line with
>"Least costly for manufacturer" category!