Message text written by "Steve TR6"
> When I had the engine rebuilt on my TR6, the mechanic used these brass
colored nuts to fasten the manifold. I actually dont know their composition
but they have the property of not seizing on the studs which is pretty
cool.
What is not cool is I cannot keep them tight. The problem seems to be that
no matter what kind of lock washer I use, the heat seems to fatigue the
metal where the lock washer looses all of its spring and just becomes
flat.
I am about to replace the manifold gasket one again and this time I want
to remedy this. Does the manifold actually depend on the nut seizing to
some
degree or is my problem really different coefficients of thermal expansion
between the different materials? Does anyone know if a lock washer I can
get
that will hold up or should I just go back to a steel nut. Oh, has anyone
tried stainless nuts?
<
Quite likely they are brass. Brass nuts are used frequently on the exhaust
manifold of Austin Healey's and Jaguar's. However, some grade 8 hardware
is given a chemical conversion treatment that has a color that resembles
brass (that is until you hold the two next to each other). You can verify
with a magnet.
I seem to recall the brass nuts are used without lockwashers, just flat
washers. If you want to use lockwashers I would try some grade 8 stuff.
Grade 8 hardware seems to stand up to heat better than the common hardware
store variety.
Dave
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