Re: Thermostat/Oil Cooler (long... but maybe useful...)

[Simon Glen <simonglen@bigpond.com>]

sml214@casbah.it.northwestern.edu wrote:

> Hey Jim-
>
> In the early 1960's when they went to the 40hp-style case, they probably kept
> the same metal because a cost-benefit analysis showed that it was cheapest to
> keep using it.  Why establish new tooling?

> Take care,
> Shad

Dear Jim and Shad,

I have followed this thread with some interest and concern.  Most of
what has been said is beyond my depth.  Nevertheless, I thought I should
pick up on one thing.

I do not understand why Volkswagen AG have persisted with magnesium
alloy cases for Type1/Type2 engines (the basis of the Type3 cases) even
to this date.  I understand that, compared to aluminium cases, magnesium
cases are virtually impossible to satisfactorily weld when cracks have
occured and that magnesium cases are a nightmare when it comes to fire. 
(I once gave up helping a Type 3 Variant owner try to put out a fire in
his engine compartment - the burning magnesium flared spectacularly and
two small fire extinguishers were useless.  Heaps of sand only slowed
the fire.  We just had to watch it burn itself out.)  For these two
reasons I like the Type 4 engines and the Wasserboxer engine.  Their
cases generally will outlast a magnesium Type1/Type2 case and can
usually be
rebuilt many times.

The other reason why I do not understand why Volkswagen AG still
persists with magnesium alloy in Type1/Type2 cases is that the very
first Type 4 engine (the 1969 "V" series which I have in my 1969 411) is
made of magnsium alloy just like the Type1/Type2 (and Type3) cases. 
Yet, VW made the change for the 1970 model year to aluminium alloy cases
for all Type4 cases thereafter.  If the costs of changing over from
magnesium to aluminium were so high for Type1/Type2 engines, why did
they do it with the Type4 engine?

Can anyone enlighten me?

Simon Glen
Toowoomba,  Australia.

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