Andy Hecker wrote:

I checked with the service manager and he said no synthetic but he was not
too
convincing. No reason why not. The mechanic backed him up but then he
mentioned
synthetic as being too "thin". I said but you can get 15 W 50 in Mobile 1
which is far from "thin". I have some contacts at Mazda so I will look into
it further. I need a reason.

Paul Lamar

Hey Paul,

  The main reason given for the RX7s was the difficulty in burning a
synthetic oil.  The synth takes a much higher temp to burn, and doesn't burn
off as cleanly.  After a period of running a synth oil, the deposits would
cause seal sticking.  This is one of the few instances where a weakness of
petroleum oil is a plus.

  Switch the injection system to another oil supply the way you're doing
with the airplane engines and the synthetic will far outperform any
petroleum-based oil in these engines.  Four-times stronger film strength,
much higher (and lower) temp capability, much more stable at all
temperatures, much better resistance to wear, and a better heat-transfer
ability.

  As you pointed out, the 'thin' argument is bogus.  It takes a certain
sized molecule to achieve a certain viscosity whether it's a
naturally-derived hydrocarbon, or a synthesized HC.

  Andy

Andrew Hecker
Commercial-Certified AMSOIL Dealer
San Antonio, TX
www.zamslube.com
210 392-3631
210 521-7635 fax

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