Date: Thu, 4 Oct 2007 17:43:29 -0400
Reply-To: greentabe-vanagon@YAHOO.COM
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Tabe Johnson <greentabe-vanagon@YAHOO.COM>
Subject: Re: Mobil I ... negative..(from digest)
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Hi Don,
Your logic is good, as far as it goes. Did the person documenting
the failures also record how many engines running Mobil 1 did NOT fail?
The really interesting number would be the ratio of (failed using M1/all
M1 users) to (failed using other oils/all other oil users).
tabe johnson/87 westy
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From: Don Hanson <dhanson@GORGE.NET>
Subject: Re: Mobil I ... negative..(from digest)
Hi,
Perhaps it was a coincidence that Mobil One was the oil most often present
in the motor-failures I was personally made aware of. For me, it is easier
to eliminate the possibility of the same coincidence happening to me, again,
by avoiding that particular type of synthetic oil.
Porsche 928 motors are known to have a design weakness (prone to oil
starvation, it was thought) in the #2/6 main bearing, and they often failed
unless this weakness was addressed by cross drilling the crankshaft, by
installation of an Accusump, or by 'dry sumping' the motor. When run at a
track under prolonged left turn high G cornering, stock motors were prone to
seizing up that particular bearing..Many instances of this were noted on our
928 Mailing list...Rennlist... One member undertook to document the type of
oil being used at the time of these engine failures, and by far the most
common oil was Mobil One synthetic..To me, that indicates Mobil One was
perhaps the least effective lubricant...Most failures=Least effective...
So yes, almost all of the 928 motor failures were proven to be
lubrication-related. The two moto engines I blew were also bottom end
bearing failures on relatively new motors..The Dayton Triumph was on it's
first fill of "real" oil after being broken in exactly as prescribed by the
Factory manual, the KTM had about one month of time on it and also blew out
the bottom on what's widely regarded as a 'bullet-proof' very dependable
motor.
Is that "proof"? Heck no...but for me, it is close enough to proof to
make me not use Mobil One and chance another coincidental motor blow up..
I ain't saying it's bad, so don't go all defensive if you love the oil...I
am saying I won't use it any more unless I can't find another brand in the
proper weight, and if I do have to put some into a motor, I change it as
soon as I can find another supply..
Ciao.
Don Hanson
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