there's been a slew of traffic about this on the porsche list; this is
a sampling. One of the claims was that Castrol GTX caused his cam to
pit, and that it stopped when he switched to Valvoline Turbo...
------- Forwarded Message
Date: Wed, 22 Aug 90 13:35 EST
From: Kevin C Gross <0004056890@mcimail.com>
To: porschephiles <porschephiles@bcm.tmc.edu>
Subject: The great oil debate
Message-Id: <52900822183525/0004056890NB4EM@mcimail.com>
And I thought heated arguments about oil were a thing of the past...
There is a wealth of contradictory opinions to be mined. One opinion expressed
was that Pennzoil sludged, and Castrol doesn't. Well, I have a mechanic here
(Lenny Cummings at Autosport) who claims just the opposite! If some brand of
oil caused pitting, I'd like to know why. Pitting and corrosion will occur if
oil is left in a driven car longer than three months. The reason? As oil
breaks down, it becomes mildly acidic. Leave that acid in your engine, and
things happen. Put fresh oil in, and pitting will stop. Pitting and foaming
will also occur in oil which has been contaminated, particularly by water
(condensation or coolant).
Pitting does not sound symptomatic of inadequate lubrication; correct me if I'm
wrong.
You cannot divine subtle differences in a lubrication product via tests
performed under grossly different conditions. Forming an opinion about the
qualities of an oil by eyeballing its adhesive properties on metal doesn't make
sense. Unless you've got your head inside an engine case that's up to
temperature and is spinning at a couple thousand RPM. Otherwise, it's about as
silly as the Mobil 1 add burning oil in a frypan.
I think race teams chose motor oil the same way 4 out of 5 leading hospitals
chose analgesics: price and sponsorship. Anyway, who cares what they chose? A
race engine gets torn down and rebuilt every 30 to 60 hours, if it lasts that
long. I can't do that, and I therefore maintain my car by a different set of
rules.
Kevin Gross
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