[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]
Re: was Re: Weepy Head Gskt Fix!is stretch bolt defence clamping methods,
-----Original Message-----
From: Avi <Avi@cosmoslink.net>
To: Mik Tip
Cc: quattro@coimbra.ans.net
Date: Sunday, December 28, 1997 12:24 PM
Subject: Re: was Re: Weepy Head Gskt Fix!is stretch bolt defence clamping
methods,
>My last comment(last question)is: if you are not using the studs "as studs"
>meaning a natural alignment, why not use bolts (raceware, if you
>want)?
Personally, I have no problems with the OEM bolts, on a "stock" motor!
I have, however, seen the OEM's allow head gasket problems from loosening!
I have worked on engines(VW & Audi)where the OEM bolts can be removed by
hand!
Attributed to factors inherant to the stretch bolts, combined with the
continual heating &
cooling, along with the different rates of expansion and contraction between
the
aluminum head and steel block!
The Raceware's are a "very precision" machined component; 40% stronger than
OEM. 190,000 psi tensile strength! 8740 Chromolly, J formed rolled threads
to
MIL spec standard's, and black oxide coated. Granted most will never need
that much, but
some do, or Raceware wouldnt be in buisness! (No affiliation)
One very important advantage of the "stud", is it doesnt "wind-up" like the
bolt when tightning.
This is important because the bolt has "stored energy" that causes it to
unwind. The "stud"
maintains correct torque retention better than the bolt.
Studs also provide a improved inherant design integrety with extra material
since they arent "required" to stretch. They're also very reusable!
The "nut & washer" are also very precise, and provide for more accurite
torque
reading's for instillation.
Of course all this comes with a price! A set for an Audi 5 cylinder costs
about $135.
The engine I built a couple of years ago had over $2000 worth of rare parts,
so the $135 was cheap insurance.
>.....here is my version (of answer), bolts are much more costly to
>make (in small quantity and from special material which i presume the
>raceware hardware is), so it is "STUDS", i am also guessing (never saw
>one), that the raceware hardware (threads) "is cut not rolled as the OEM
>factory is?........
Rolled!
The initial start of this thread focused on the "weeping head gasket".
Largely, I believe, is caused from the OEM stretch bolts, loosening.
Granted, this loosening may be very minute, and combined with a
"squashed" head gasket, take some years and mileage to develop.
The only way to correctly "fix" the weeping gasket, is to change it!
Installing the OEM bolts "may" allow the same problem to re-occur
later on in the engines life. But most folk's dont keep a car that long!
The Raceware's are an "improved alternative" to the OEMS, but at
a price!
Mainly recommended as a "performance" type option for those
seeking more "reliable" fastening of vital components, especially
on "modified" engines.
Mik