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Re: Whats the sodium for?
> So, the way I read this is that Audi used sodium-filled valves on the turbo cars because the standard
> valves were not up to the job and SS must have been too expensive for production use?
I doubt that the cost issue prevented the use of SS. SS is about 10%
_less_ thermally conductive than regular carbon steel. If _that_ has
heat trouble, the SS surely will.
'87 4kq, plain valves
'89 200q, sodium and K26
'64 Falcon, plain valves, 16 hardened seats
> There is an aspect of apples vs. oranges here. Valve longevity is aided by
> both cooling and temperature resistance. Given a metal with sufficient
> ductility, hardness, whatever for valve use, then higher temperature
> resistance is better. This is generally associated with high nickel content
> (SS, Nimonic 80A, ...)
> For better cooling, sodium can be used to transfer heat from the valve head
> to the stem, where the oil splashing about can cool it. It was my
> understanding that sodium-filled valves were only partly filled, so the
> sodium was cycled from head to stem as the valve moved up and down (or vice
> .... Kirby (Kirby A. Smith)
> 2 x 1988 90q
> New Hampshire USA