Re:sulfer in fuel/94'-95' 4.0 litre engines

[Phil Marx <BMW@xxxxxxx>]

Randy wrote:
>If you are like Mercedes-Benz and want to go very esoteric, you cast your
>alluminum block WITH pure silicon, "etch" your cylinder walls with chemicals
>to leave a exposed layer of pure silicon (which is the most dirable of
>reciprocating parts surfaces) and then do final machining.

It's apparent there aren't many left on this list who've owned a BMW for
more than two years, but the Alusil (aluminum/silicon alloy block bored
then etched to expose silicon surface) has been used by BMW in all
12-cylinder cars since '88.  Porsche used it in since '77 in all V8s and,
I'm told, Chevy used it in the Vega. ('71?)  Now since BMW has also been
using the Galnikal/Nikasil coated bores on motorcycles since the K-bike was
intro'd in '84 and the process has been used in aero motors for quite some
time, what more research should have been necessary?  A BMW K-bike motor is
good for 1/2 million miles.  Those torn down with minor valve problems at
near 300k had perfect bores.  And I've never had a need for Techron in a
2002 either, but new technology and new pollutants of all sorts will effect
many different things in the future.  Maybe the fuel is to blame.

I'm not defending BMWs practices.  It is obvious that coated bores cost
less than alusil casting process and they maybe should have considered
spending more in the first place, but to say the process is unique to BMW
V8s is not accurate.  Maybe the change in crude oil sulphur content is the
real problem, maybe it's something else.  I'm not sure the real cause is
known yet.

- -Phil

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