<VV> Re: Engine Oil

[N. Joseph Potts]

The 15W40 "Diesel" (yes, the numerical majority of its applications are
Diesel) oil is SPECIFIED for one GASOLINE engine I own: that of my 1997 BMW
M3. Exactly why BMW would specify that oil for that engine, I'm not sure,
but: (a) the car is, and is in many ways designed to be used as, almost a
race car (of course it's street legal); and (b) that particular engine has
an oil capacity of about seven quarts, unlike other BMWs and, of course,
Corvairs. The applications and packaging make me think of it as targeted at
truck engines.
     On its package, the oil shows many Diesel (C*) ratings, and two
GASOLINE ratings: SJ and SL.
     I would expect the stuff to be just fine in a Corvair engine in all but
the coldest locations. But I use synthetic 10W30.

Joe Potts
Miami, Florida USA
1966 Corsa coupe 140hp 4-speed with A/C


-----Original Message-----
From: virtualvairs-admin@corvair.org
[mailto:virtualvairs-admin@corvair.org]On Behalf Of Garth Stapon
Sent: Thursday, February 17, 2005 6:20 PM
To: virtualvairs@corvair.org
Subject: <VV> Re: Engine Oil

A few years back, we had a guest speaker at an Ontario Corsa chapter
meeting.  The discussion was on motor oil.  The gentleman who gave the talk
worked in the development lab of ESSO the Canadian arm of Exxon/Mobile
located in Sarnia, Ontario, Canada where they do their global lubricant
development.  He said that ESSO located it there because they were 100 miles
away from minus 40 degree C weather (a typical January temperature in
Northern Ontario)

As we know our beloved air cooled engine causes oil to operate at a higher
temperature when compared with a water cooled unit.

He made some interesting comments that I thought I might share.

1) Standard multi grade grade 5W30 oil with an energy conserving rating have
friction modifiers in them to squeeze out additional mpg at the expense of
longevity. (seems that CAFE is driving this and the automakers want to
squeeze out extra mpg to avoid penalties)
2) Diesel oil grade 15W40 has anti wear additives instead of friction
modifiers as Mack, Cummins, Cat etc want their engine to last a million
miles.  Running it in a gas motor will mean a slight penalty in fuel economy
(1 - mpg) Look at the label for which Companies certify the oil . If the
list is long, the product is good. This grade of diesel oil is rated to run
up to minus 20. I run this grade in summer and synthetic in winter (for cold
flow characteristics).  As most of you know, diesel oil can be run in a
gasoline car (I have been doing it for years and even use it in my
motorcycle)
3) The wider the viscosity range in the oil, the greater the compromises in
development. (This was new to me) He actually suggested that a tighter
viscosity window was better- (Is this why Honda and Ford now recommend 5W20
in some cars?)
4) His oil recommendation for a Corvair was 20W50 full synthetic (not all
synthetics are created equally). He suggested this because not many of us
run our Corvair's in winter. (I use Mobile 1 0W40 in my wife's car all
year). Volkswagen just issued a technical bulletin on their 1.8 turbo motor
that a switch to synthetic would extend the engine warranty to 100,000
miles.