Slipstream - October 2017

Lube for Thought: Lubrication, Part 1
By Mike Mahoney, Region Concours Chair
Photos courtesy of the Author
his is the first in a series
T
of articles on lubrication
and how important
it is to you and your car.
We all know we need engine oil. But
do you know its various functions?
Do you know what types of additives
are needed in engine oil and
why? Do you know why you need to
change your engine oil? What’s the
difference between engine oil and
gear oil? Grease, what is it? We will
tackle these questions and more.
I’ll begin with the basics of engine
oil and then move on to gear
oil and grease.
You’ve probably heard the
phrase “oil is the life blood of your
engine.” While that happens to be
true, it’s especially true in Porsches.
One reason is the high-revving engines.
And in air-cooled engines,
it’s the high heat.
In an air-cooled engine, about
8% of the heat generated by the
engine finds its way into the oil. As
all of us air-cooled nuts know, those
engines get pretty hot! And I know
8% may not seem like a lot, but every
degree in temperature equates
to increased oxidation of the oil
or thickening of the oil. For every
10-degree increase of the oil, the
rate of oxidation doubles.
18 October
Dirt is another enemy of oil. Oil
deteriorates from the various contaminants
that find their way in to
the crankcase. Dirt from dirty air
filters, cracks in the air system, as
well as from limitations in air filter
design and from crankcase ventilation
systems. The oil also picks up
metal particles from normal wear
of engine parts, and if not removed,
can cause premature wear as well.
There are various additives in
engine oil. Additives for neutralizing
acids, anti-wear additives,
dispersants, etc. Over time, the oils
additives are depleted and are unable
to do their job of neutralizing,
suspending, dispersing, and solubilizing
contaminants. Oxidation
of the oil itself happens over time
for the same reasons, and is accelerated
by heat. In addition, the
combustion process is dirty business,
as a result of the thousands
of explosions going on inside the
combustion chamber in each of
the cylinders. One of the byproducts
of combustion is water. Most
of the water that comes from the
combustion process is in the form
of steam or water vapor and goes
out the exhaust. But at low temperatures
and short trips, the water
condenses and sticks to cylinder
walls, ultimately making its way into
the crankcase and the oil. This can
lead to the formation of sludge and
corrosion of metal parts.
There are also acidic gases produced
by the combustion process.
They too adhere to the cylinder
walls at low temperatures and end
up in the oil. They combine with the
water and become corrosive. Additives
assist in in preventing damage
from these factors but you have to
regularly change your oil. It’s the
only way to get rid of the contaminants
and acids that are suspended
in the oil. The filter will not remove
everything, and with the additives
being depleted, it won’t be able to
continue to do its job.
Well, as you can see, your oil is
working hard for you. So do your
part. If your engine oil could talk,
it would be doing its best Jerry Maguire:
“help me help you!”
That covers the basics of engine
oil. Next time we will talk about viscosity,
synthetics, and gear oil. Did
you know that viscosity is the single
most important factor when selecting
any lubricant? So what is viscosity?
See you next time.
Mike Mahoney spent over 35 years
with ExxonMobil where he worked in
lubricant manufacturing and sales. He
retired 2 years ago and is a 1 year PCA
Maverick Region member.