Sender: <marv@lancaironline.net> (Marvin Kaye)
To: flyrotary
Date: Thu, 26 Sep 2002 19:45:34 -0400
Message-ID: <redirect-1792006@logan.com>
From: Mark Steitle <msteitle@mail.utexas.edu>
Subject: Re: [FlyRotary] Re: Synthetic oil?
In-Reply-To: <list-1791106@logan.com>
Mime-Version: 1.0
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At 07:56 PM 9/25/2002 -0400, you wrote:
>Posted for "Tracy Crook" <lors01@msn.com>:
>
>>Bottom line is that I bought some Mobile 1, 10W-30, and plan to use it in
>>the car and the plane, but I thought I'd see if any of you know why Mazda
>>say's not to use synthetic.
>
>The problem in the car is that the oil injection sends significant unburned
>synthetic oil out the exhaust and it eventually clogs up the catalytic
>converters. A very expensive thing for the dealer since they must certify
>the emissions system for 100,000 miles.  The engine itself loves the stuff.
>I have around 1200 hours in the plane on Mobile1.
>
>Tracy Crook
>tcrook@rotaryaviation.com
>www.rotaryaviation.com
Tracy,
Do you normally burn 100LL or MOGAS?  The attached message(s) address a 
problem with the higher lead content in avgas that synthetics have trouble 
dealing with, possibly plugging oil passages, therefore not advised to run 
in aircraft that burn leaded avgas.  Has that issue been resolved with the 
"newer" synthetics, or is it still something to be concerned with?
Mark Steitle

<Attachment>
Subject: Mobil One - WARNING!


 > >> > > DON'T RUN MOBIL1 WITH AVGAS!!! YOU WILL SUFFER BLOCKED OIL 
PASSAGES AND
 > >> > ENGINE
 > >> > > FAILURE!!!!
 > >> > >
 > >> > > Mobil1 will not properly disperse the lead left in the engine from
 > >> blowby
 > >> > gasses.
 > >> > > Standard old crappy oil and semi-synthetic blends (run 50%/50% might
 > >> work..
 > >> > ..) will
 > >> > > chemically react with the lead compounds and suspend it properly 
till
 > >> oil
 > >> > change. I
 > >> > > would guess if you are flying with mogas this is a non-problem.
 > >> > >
 > >> > > This is why it got yanked off the market after a few accidents 
proved
 > >> this
 > >> > sorry fact
 > >> > > out.
 > >> > >
 > >> > > I run 15w-50 all year long in my bikes and cars.
 > >> > > Blake

 > >> > Come to think of it I vaguely heard that someplace.
 > >> > I forgot about that Blake. Thanks.
 > >> > Too bad.
 > >> >
 > >> > Paul Lamar

 > >> Was it Mobil One or a Shell synthetic that was being sold for Aero 
use? I
 > >> think it was Shell --- may be a moot point, because Mobil One was 
designed
 > >> and sold for automotive use only. However it was introduced when 
there was
 > >> still some lead in Motor fuel. Did it have problems then?
 > >>
 > >> Is the problem that of the increased blow-by of aviation engines 
compared to
 > >> automotive engines?
 > >>
 > >> Bill Schertz
 > >> KIS Cruiser #4045
 > Bill,
 >
 > Shell only sells a semi-synthetic (which I use) for that reason. Mobil came
 > out with an aircraft version of Mobil One, which I forget the name of, and
 > it caused some serious problems, wrecked a number of engines, and they
 > withdrew from the market. Sad to say, the requirements of a high specific
 > output (and they ARE, when you look at RPMs) air cooled motors is not
 > the same as low specific output (and car motors ARE, when you look at
 > the actual hp used) water cooled motors. One major question is the
 > conductive ash deposits left by auto oils, which were a serious plug
 > fouler in the large radial motors of the 40s and 50s because they used
 > a lot of oil. As the more modern opposed motors get a better handle
 > on oil consumption this may be less important, but it is a major difference
 > between auto oils and aircraft oils. Aircraft oils use no or a non-ash
 > producing detergent additive.
 >
 > This is a HUGE topic, and probably not too relavant to the rotary which
 > has modest bearing lube requirements and 2 stroke oil burning (residue)
 > requirements, possibly a bit like the old radials that way, but I think the
 > direct injection of 2 stroke oil, or mixing in the gas and only using the
 > crankcase oil for bearing lube and internal cooling is the right solution.
 >
 > Bill Freeman
 > Long EZ builder & pilot
 > BSME, MSME
 > EAA Technical Counselor