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The True Measure of Lubricant
Quality By Ed Newman
This article appeared in Power Stroke Registry,
Summer Edition 2003
Making and recording measurements has been one of
the hallmarks of the Age of Enlightenment. It seems like modern people measure
everything. We have measures of time, such as weeks, hours, minutes, and years.
We have measures of mass, such as grams, pounds and tons. We have measures of
sound volume, of energy, of radioactivity, of pressure, of type font
face="verdana" sizes, of land mass, and of speed.
AUTOMOTIVE RELATED
MEASUREMENTS Horsepower, as you might guess, is the amount of power
exerted by one horse pulling. After many careful measurements James Watt,
inventor of the steam engine, determined that a horse can lift 550 pounds at a
rate of one foot per second, which translates into 745.7 watts. Some clever
American engineers decided that manpower should have a measurement as well,
equivalent to 0.1 horsepower or 74.57 watts.
MPG is the familiar acronym for miles per gallon,
which measures the rate of fuel consumption in a motor vehicle. One mile per
gallon equals approximately 0.4252 kilometers per liter. MPH is our common
measure of speed. One mile per hour equals 22/15ths feet per second or 1.609
kilometers per hour or 0.447 meters per second.
RPM means revolutions per minute, a unit of
frequency as a measure of rotation rates in mechanics. In cars RPM is measured
by a tachometer. Some motorists pay attention to RPM so they don't over rev and
cause component failure. Race car drivers try to keep RPM rates in a range that
will provide maximum power.
OIL MEASURES
A quart as a unit of volume is so named because it
represents one quarter of a gallon. When measuring liquid, one quart is 32 fluid
ounces, or 57.75 cubic inches. On the other hand, when measuring dry goods like
pecans or blueberries, a quart is 67.201 cubic inches. Go figure.
Drums are sometimes used for measuring oil,
containing 55 U.S. gallons or about 208.198 liters. Drums are not the same as
barrels, the standard unit of volume for measuring crude. One drum is equivalent
to 1.3095 barrels. A barrel is equivalent to 42 U.S. gallons, which is
coincidentally the same size as a traditional wine barrel, more commonly called
a tierce.
But what about oil quality? What are the criteria that are
important when measuring the performance quality of a motor oil?
Part of the answer comes from understanding the
role that motor oils play when it comes to engine lubrication. Another part of
the answer comes from understanding that we live in a scientific age in which
nearly everything can be, and often has been, measured. Knowing what to measure
and how to measure it is an important part of good decision making. We're
talking motor oil here.
THE ROLE OF MOTOR OIL
Before we can discuss what makes a good motor oil,
it helps to understand what role motor oil actually plays in the performance of
an engine.
While motor oils serve a variety of functions, they
are primarily necessary to lubricate and to cool the engine. When the engine is
at rest, the motor oil sits in the bottom of the engine block in what is called
the oil pan. Upon start-up, an oil pump feeds oil from the pan to the oil
distribution system by means of a network of passages, tubes, grooves and holes
leading to the engine bearings and other surfaces needing pressurized oil for
lubrication. Other parts, like the overhead valve system, receive a carefully
controlled quantity of non-pressurized oil through splashing or spray.
In
addition to lubricating and cooling engine parts, motor oil must allow easy
starting, protect the engine from corrosion and oxidation, keep the engine
clean, form a tight seal between piston rings and cylinder walls and help the
engine use fuel efficiently.
In days gone by motor oil was made from the
throwaway byproducts of a barrel of crude oil after everything useful was taken
from it. In those early days the filter, if you had one at all, was a by-pass
type, filtering only a small percentage of the oil. In some instance the filter
was little more than a screen and the oil was changed every five hundred or
thousand miles. (Some of us recall grandpa's stories of tires needing to be
changed on every trip to town, the idea of longevity being somewhat foreign back
then.)
As cars and their engines became more
sophisticated, so too the requirements of a lubricant became increasingly
demanding. In the 1960's jet fighter pilots and their mechanics were becoming
aware of the advantages of synthetic oils, and a few of them experimented with
the notion of synthetic lubrication for automobiles. One of these pilots, Lt.
Colonel Albert J. Amatuzio, went further than the haphazard experiments of his
peers. His ten year quest resulted in the development of AMSOIL, the first
automotive synthetic motor oil to exceed the certification requirements of the
American Petroleum Institute (API).
SYNTHETIC VS. CONVENTIONAL
PETROLEUM
Conventional lubricants are refined from crude oil
which has thousands of types of molecules. Refining is a process of physically
separating the impurities from the oil and further separating the light and
heavy components. Because refining separates products by weight, it groups
molecules of similar weight and dissimilar structure. The result is a lubricant
with a wide assortment of molecules. Some of the substances in crude oil are
detrimental to lubrication. Paraffin, for example, are a common conventional
oil contaminant that causes motor oil to thicken in cold
temperatures.
Synthetic motor oils are made from pure chemicals, not
refined crude. Their components are chemically reacted to produce finished
products with pre-designed performance characteristics. Because of their
molecular uniformity, they excel in reducing friction, which improves fuel
efficiency, controls heat and reduces wear. This molecular uniformity also helps
synthetics resist thinning in hot temperatures and thickening in
cold.
MEASURES THAT MATTER
The American Society for Testing and Materials
recognized the need for uniform procedures that can be duplicated and verified
by laboratories in any location. The goal of establishing standards is so
important that the official publication of ASTM International is called
Standardization News.
Founded in 1898 and completely voluntary, ASTM is
now one of the largest non-profit standards development systems in the world.
The organization currently has 134 committees that write standardized test
methods for materials, products, systems and services. More than 8500 ASTM
specifications have been established for products as diverse as metal, paints,
plastics, textiles, energy, consumer products, medical services and instruments
and even the environment.
Developing standard measurement methods is part of
the task of ASTM. Equally important is determining what measures are important,
tests that actually correspond to what the function of motor oil is intended to
fulfill. What follows here are some tests commonly used to evaluate motor oil
performance.
ASTM D-445 Kinematic Viscosity The proper
operation of equipment depends on the proper kinematic viscosity of the oil at
operating temperatures. Kinematic viscosity is a measure of a liquid's flow
under the influence of gravity. Some companies formulate their lubes to tighter
specs than others. One recent study revealed that one in five off-the-shelf
motor oils tested were outside the acceptable performance range for their stated
viscosities.
ASTM D-2270 Viscosity Index This test
indicates how much a lube's viscosity will change according to changes in
temperature from 40 degrees C and 100 degrees C. The higher the viscosity index
the better for motor oils that must perform in locations with temperature
variations.
ASTM D-5293 Cold Crank Simulator Apparent
Viscosity Cold crank viscosity affects the startability of engines in
cold temperatures. Low cold cranking viscosities make for easier cold cranking
and more dependable cold temperature starting, and less drain on
batteries.
ASTM D-3829 Borderline Pumping Temperature This test
is used to predict the lowest temperature at which a motor oil can be
continuously and adequately supplied to an engine¹s components. As the name
suggests, the lower the temperature, the better the oil circulates in cold
weather. Synthetic oils are famed for the extreme low temperature
protection.
ASTM D-97 Pour Point This test identifies
the lowest temperature at which oil flows.
ASTM D-92 Flash Point and Fire
Point Flash point indicates the temperature at which a specimen vapors
will ignite. Flash point assesses the overall hazard of a material and is
used in shipping and safety regulations to define "flammable" and "combustible"
materials. Fire point measures the temperature at which a specimen will remain
burning for five seconds. Synthetic lubricants with high flash and fire points
are safer to use and transport than petroleum lubes with lower ones. High flash
point is indicative of a greater high temperature operating range and better
quality base stock.
ASTM D-4683 High Temp, High Shear
Viscosity This test is representative of the conditions encountered in
the bearings of automotive engines in severe service. Lubricants with high
scores, such as premium synthetics, maintain their viscosity in high
temperatures after exposure to high shear. This means that they continue to
protect bearings even after exposure to severe service conditions.
ASTM D-892 Foaming Tendency This test is
important because of the turbulent environment in which motor oils are required
to perform. Foaming can lead to inadequate lubrication, cavitation and
mechanical failure.
ASTM D-4172B Four Ball Wear Test The
Four Ball Wear Test determines the relative wear prevention properties of
lubricants in sliding contact. The test involves three fixed balls in a bath of
lubricant with a fourth ball in rolling contact under pressure at a specific
level of severity. Wear protection is gauged by measuring the wear scar that
develops. A smaller wear scar means better protection in typical engine
operations.
ASTM D-5800 Noack Volatility Oil
volatility is the measure of how susceptible oil is to boil-off under high heat
conditions. Petroleum oils experience significant boil-off during high
temperature engine operation and subsequently higher oil consumption.
Evaporation loss contributes to damaging deposits, sticky piston rings and oil
blow-by, resulting in a drag on performance and reduced engine life. Synthetic
oils are far more impervious to this kind of degradation. The lower volatility
of synthetics is another reason they are also better for the environment than
conventional products.
SAE J1321 Joint TMC/SAE Fuel Consumption Test
Procedure - Type II The Society of Automotive Engineers has devised a
test to measure fuel consumption and fuel economy. In a demonstration involving
over-the-road trucks an improvement of 8.2% was achieved by switching from
conventional lubes to synthetic lubricants (in this case AMSOIL products) in the
drive train and engine.
Here's an interesting, undisputed fact. By every
one of these measures premium synthetic motor oils are superior to conventional
petroleum motor oils. This truth is never even questioned by industry
professionals.
So why, one might ask, isn't everyone using
synthetic motor oils and lubes? Here's one possible reason. To divert attention
away from the performance measures above the major oil companies focus on one
other measure: price.
PRICE Ironically, we live in an era in
which people are spending more money than ever on large vehicles or cool looking
vehicles -- PT Cruisers, SUVs, Hummers, and dualies. Insurance payments alone in
most households run ten times greater than motor oil costs. People are
passionate about their vehicles. How can they not be equally dedicated to
protecting their investment by using premium lubricants that promise longer life
to the object of their passion. You wouldn't expect price to be that big of a
deal, yet it is for some people. For this reason the price myth must be
addressed.
When people talk about price, they generally think
in terms of initial cost instead of life cycle cost. Price is only an issue if
you apply the 3,000 mile oil change rule to all motor oils alike. In truth, the
service life of synthetics can be extended much longer due to their resistance
to oxidation and other forms of degradation. With proper filtration engine oil
can be safely used for much longer periods, and is thereby less costly than
petroleum in the long run. Add to this the reduced fuel consumption, fewer
maintenance bills and optimal performance characteristics and running anything
but a premium synthetic motor oil should not even be a consideration.
CLOSING THOUGHTS
As you can readily see there is no single measure
that stands alone as the signature of superior performance. A motor oil serves a
variety of functions in a range of roles inside the engine. What tests do show
is that synthetic motor oils as a class are far and away superior to petroleum
based products.
I welcome the opportunity to work with you personally as your servicing
AMSOIL Dealer. Use the information on this website to contact me. You may also
check out the AMSOIL Corporate Website for product and
business opportunity information.
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