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What Is a Motor Oil?
The four primary purposes of a motor
oil are lubrication of all moving internal engine parts to minimize
friction and wear, cooling the engine, contamination and corrosion
control, and sealing the piston rings and other mating surfaces.
 A
motor oil is made up of two basic components:
base stock and additives.
The base stock makes up the majority of the completed
oil. The functions of the base stock include lubrication of internal
moving parts, heat removal and sealing piston rings. Motor oil base
stocks can be made from: 1) Petroleum, 2) one or several synthetic
chemicals, 3) a combination of synthetics and petroleum (called para-synthetic,
partialsynthetic or synthetic-fortified).
A
petroleum base stock consists of many different oil fractions
blended together to form the final product. Some of these fractions
will "boil off" at relatively low temperatures. Generally, molecules
of a petroleum base stock are long carbon chains which are sensitive
to the stress of heat. Engine temperatures encourage these chains to
break down, changing the physical properties (such as viscosity) of
the motor oil.
A synthetic base stock is generally composed of uniformly shaped
molecules that are resistant to the stress of heat. AMSOIL Synthetic
Motor Oils exhibit a very low "boil off" rate. There are no
excessively long carbon chains in their structure to break down and
alter the physical properties (such as viscosity) of the oil.
The functions of the additive system include anti-wear, anti-foam,
corrosion protection, acid neutralization, maintenance of viscosity,
detergency and dispersancy. The additive system is composed of
various chemicals that do these specific jobs. Their quality varies
widely throughout the lubrication industry, ranging from a bare
minimum in some oils (to just meet certain requirements) to
exceptionally high quality, as in all AMSOIL Motor Oils.
Improvements in Oil
Motor oils today are vastly different from motor oils 30 years ago.
Because of new demands placed on lubricants due to modern engine
design, today's oils must meet stringent requirements in areas of
viscosity, wear protection, corrosion protection, acid
neutralization, detergency and dispersancy. Variations in these
factors determine which service classification rating and viscosity
grade an oil receives.
Viscosity
One of the most important properties of an oil is its
Viscosity. This refers to the
internal cohesiveness of the oil or its resistance to flow. An oil
must be able to flow at low temperatures to lubricate internal
moving parts upon starting an engine. An oil must also remain
viscous or "thick" enough to protect an engine at high operating
temperatures.
Viscosity Index Improvers are
additives that extend a multi-grade motor oil's viscosity range.
Viscosity Index (VI) indicates
an oil's viscosity characteristics over a wide temperature range.
The less an oil's viscosity changes with temperature changes, the
better the oil protects the engine. An oil that changes little with
temperature changes receives a high VI and an oil that changes
greatly with temperature changes receives a low VI. Better oils have
high VIs.
The VI is measured by comparing the viscosity of the oil at 40�C
(104�F) with its viscosity at 100�C (212�F). It does not indicate
the performance of an oil at low or high temperatures.
Cold Temperature Protection
Pour Point refers to the temperature at which an oil has solidified,
due to cold temperatures, and can no longer pour.
The Cold Crank Simulator
measures the speed at which a shaft can turn in cold-thickened oil
and evaluates the "startability" of the oil. An engine must be able
to reach a turning speed above 300 rpms for the engine to start.
The Mini-Rotary Viscometer
measures the speed at which a shaft can turn in cold-thickened oil
and evaluates the "flowability" of the oil. An oil must flow to the
oil pump inlet to be circulated through the engine for lubrication
and wear protection. The results of the Cold Crank Simulator and
Mini-Rotary Viscometer are used to assign an oil's SAE "W" grade. In
multi-grade or multi-viscosity oils such as 10W-30 and 10W- 40,
chemical additives called Pour Point
Depressants are often added to the oil to allow it to
flow enough at cold temperatures for the oil pump to be able to
circulate the oil to all parts of the engine.
Volatility
Petroleum multi-viscosity oils have various chemical ingredients in
them that allow them to protect engines in a wide range of
temperatures. Some of these ingredients are used to keep the oil
flowing when it is cold. However, these ingredients are very
volatile, and through their normal use in an engine (especially when
it is hot), these ingredients evaporate, or boil off. Lighter
fractions of a petroleum base stock also boil off in heat, which
changes the viscosity of the remaining oil. The oil left behind in
the crankcase is thicker and doesn't flow easily when it's cold.
This thick oil can take up to five minutes to freely circulate in a
cold engine after starting it. Meanwhile the engine is being starved
of oil and not being protected against friction and wear.
Wear Protection
One of an oil's main functions is to lubricate moving parts to
prevent friction and wear. The oil forms a thin film on, around and
between parts which work in close proximity with one another.
Ideally, a constant flow of oil keeps those parts from rubbing
together. Metal to metal contact creates tremendous frictional and
thermal forces that can actually weld moving parts together, causing
the engine to seize. Today's modern oils do a very good job of
preventing engine seizure once the engine has warmed up. At
start-up, however, when there is little oil on moving parts to
lubricate them, metal to metal contact can occur. A good motor oil
contains: Anti-wear Additives
to protect engines by bonding to metal surfaces and forming a
protective layer between moving parts. This layer does not prevent
their rubbing together but minimizes the effects of contact.
Oxidation
Oxidation is the chemical breakdown of oil due to the extreme heat
in the engine. Oil oxidation can cause acidic gasses and sludge to
form in the crankcase. Acidic gasses combine with water in the
crankcase to corrode and rust the engine. Corrosion is especially
critical in diesel engines.
To counteract the effects of acids, neutralizing additives are
blended into motor oil. An oil's neutralizing capability is
expressed by its Total Base Number (TBN).
Most oils for diesel engines in North America have a TBN
between 7 and 10, which is sufficient for the sulfur content of
diesel fuels found here. AMSOIL manufactures a diesel oil with a TBN
of 12. A typical TBN for a gasoline engine motor oil is 5 or 6.
Detergents and Dispersants
Combustion causes carbon buildup and deposit formation on the
pistons, rings, valves and cylinder walls. Carbon and deposits
affect engine temperature, oil circulation, engine performance and
fuel efficiency. Additionally, some combustion by-products slip past
the piston rings and end up in the motor oil. These by-products can
clog the engine's oil channels.
Detergents are added to the oil
to keep the engine clean. They prevent the build-up of carbon or
deposits from burned and unburned fuel and even from the oil itself.
Dispersants are added to
prevent the agglomeration of sludge and dirt in the oil. Dispersants
hold the dirt particles in suspension rather than allowing them to
come together and form deposits. The particles suspended in the oil
are eventually removed by the oil filter.
Foaming
Tiny air bubbles are constantly being "whipped" into motor oil by
the action of many rapidly moving parts inside the engine. The
result is a mass of oily froth called
Foam. This foam has very little capacity to lubricate or
aid in the cooling of the engine. It is important to minimize
foaming in motor oil. The addition of silicone or other compounds in
very small amounts makes most oils adequately foam-resistant.
Seal Swell
All motor oils must be compatible with the various seal materials
used in engines. Oil must not cause seals to shrink, crack, degrade
or dissolve. Ideally, oil should cause seals to expand or "swell"
slightly to ensure continued proper sealing.
All AMSOIL Motor Oils exhibit excellent seal compatibility with
Fluorocarbons, Buna-N, Silicone, Viton and other commonly used seal
materials.
Heat Dispersal
Motor oil helps cool the engine. The radiator/anti-freeze system is
responsible for only 60 percent of the engine cooling that takes
place. This cools only the upper portion of the engine, including
the cylinder heads, cylinder walls and valves.
The other 40 percent is cooled by the oil. The oil is directed onto
hot surfaces, such as the crankshaft, main and connecting rod
bearings, the camshaft and its bearings,the timing gears, the
pistons and many other components in the lower portion of the engine
that directly depend on the motor oil for cooling.
Engine heat is created from both friction of moving parts and the
ignition of fuel inside the cylinder. Oil carries heat away from
these hot surfaces as it flows downward and dissipates heat to the
surrounding air when it reaches the crankcase.
The amount of oil required to lubricate an engine is actually very
small when compared to the amount needed to ensure proper cooling of
these internal parts.
The oil pump constantly
circulates the oil to all vital areas of your engine.
Classification Systems
Oil is classified according to two
systems. One system determines the oil's viscosity (the SAE grade),
and one system determines its performance level, i.e. which oil to
use in what type of engine (the API class).
I. SAE Grade
The Society of Automotive Engineers (SAE) Viscosity Grade is a
system based on viscosity measures taken from a variety of tests.
This system established eleven distinct motor oil viscosity
classifications or grades: SAE0W, SAE5W, SAE10W, SAE15W, SAE20W,
SAE25W, SAE20, SAE30, SAE40, SAE50 and SAE60. These are known as
single grade or single viscosity oils.
These grades correspond to specific ranges that the particular oil
falls into. The "W" in the classification indicates that the grade
is suitable for use in cold temperatures. (You can think of the "W"
as standing for "Winter.") The classifications increase numerically,
allowing you to tell the difference between them and what this
difference means. In simple terms, the lower the number, the lower
the temperature at which the oil can be used for safe and effective
protection. The higher the number, the better protection offered for
high heat and high load situations.
 Single
grade oils have a limited range of protection and so have a limited
number of uses. In order to increase an oil's usefulness, it must be
able to meet the requirements of two or more classifications.
Multigrade or multi-viscosity oils effectively meet the viscosity
requirements of two or more classifications. Examples of
multi-viscosity oils are SAE5W-30, SAE10W-30, SAE15W-40 and
SAE20W-50. The number with a "W" focuses on an oil's properties at
low temperatures. The number without a "W" characterizes properties
at high temperatures. A multiviscosity or multi-grade oil, e.g.
10W-30, meets the 10W criteria when cold and the 30 criteria once
hot. SAE10W-30 and SAE5W-30 are widely used because under all but
extremely hot or cold conditions, they are light enough for easy
engine cranking at low temperatures, and heavy enough to protect
satisfactorily at high temperatures.
II. API Class
The American Petroleum Institute (API) developed a classification
system to identify oils formulated to meet the operating
requirements of various engines. The API system has two general
categories: S-series and C-series.
The S-series service classification
emphasizes oil properties critical to gasoline or propane fueled
engines. If an oil passes a series of tests in specific
engines (API Sequence tests), the oil can be sold bearing the
applicable API service classification.
There are ten S-series classifications: SA, SB, SC, SD, SE,
SF, SG, SH, SJ, and SL The S-series classifications
progress alphabetically as the level of lubricant performance
increases. Each classification replaces those before it, with SL
currently offering the most protection. SL oil may be used in any
engine, unless the engine manufacturer specifies a "non-detergent"
oil.
SA and SB are nondetergent oils and are not recommended for use
unless specified. SC oils were required for new car warranties from
1964 to 1967. SD oils were required from 1968 to 1970 and a few in
1971. Some new car warranties required SE oils in 1971 and its use
continued through 1979. New car warranties from 1980 to 1989 require
SF oils. New car warranties from 1990 to 1993 require SG oils.
New car
warranties beginning with the 1994 model year require oils with an
API SH performance rating. New car warranties beginning with 1997
require an API SJ oil. The year 2001 brought the introduction of SL
oils. SL oils are designed to increase fuel economy, reduce
emissions and protect hot, hard-working engines over the course of a
very long warranty period.
C-series classifications deal with diesel
engines. There are eight classifications: CA, CB, CC,
CD, CD-II, CE, CF-4 and CG-4. CH-4, CA, CB, CC and CD performance
rated oils are no longer used in diesel engines. However, oils used
in turbocharged gasoline engines retain CF as part of their
performance designation: SH, CF.
Unlike S-series classifications, C-series classifications do not
supersede one another. The current classifications, CF, CF-2 and
CH-4, are specified for various applications.
CF for Indirect Injected Diesel Engine
Service. Service Category CF denotes service typical of
indirect injected diesel engines and other diesel engines which use
a broad range of diesel fuels in off-road applications, including
diesel fuel with greater than 0.5 percent sulfur by weight. CF oils
may be used in place of CD oils.
CF-2 for Two-Stroke Diesel Engine Service.
Service Category CF-2 denotes service typical of
two-stroke engines requiring highly effective control over cylinder
and ring-face scuffing and deposits. CF- 2 oils may be used in
engines for which CD-II oils are recommended.
CH-4 for Severe Duty Diesel Engine Service.
Service Category CG-4 denotes service typical of high
speed four-stroke diesel engines used in heavy-duty on- and
off-highway applications. CH-4 oils are especially effective in
engines designed to meet 1998 exhaust emission standards. CH-4 oils
may be used in place of CD, CE, CF-4 and CG-4 oils.
The SAE and API classification systems are intended to help
motorists choose the right oil for their needs. The choice depends
on the engine, the outdoor temperature and the type of driving the
motorist does most. Most motorists are more familiar with the SAE
Viscosity Grade system than they are with the API Class system.
SJ is the current API class. SJ oils are widely available and most
gasoline engine automobiles either specify SJ oil or, if they were
manufactured before the SJ class was created, may use SJ oil.
However, one should be sure to purchase SJ class oil for the best
engine protection available. Of course, motorists should follow the
oil specification of their vehicle owner's manual.
Turbocharged Engines
Turbocharged engines (both gasoline and diesel) are different from
conventional combustion engines and thus have different lubrication
requirements.
A turbocharger compresses incoming air, then feeds this compressed
air into the intake manifold, packing a higher density air to fuel
mixture, which upon combustion can yield as much as 10 to 20 percent
more horsepower.
The smaller engines being turbocharged in some contemporary cars run
at higher RPMs than normal engines do. Higher RPMs require a higher
quality oil because more stress is placed on the engine.
Turbo engines run much hotter than normal engines run. Heat causes
three main problems for lubricating oil. First, wear-promoting
viscosity losses are their most damaging in heat. Second, there is
more carbon build-up and deposit formation with the higher heat,
reducing the car's performance and efficiency. Third, oxidation
occurs more rapidly at higher temperatures, which increases
corrosion.
Because turbocharged engines run so hot, they should be idled to
cool the turbo bearing and the oil before the engine is shut off. If
the engine is shut off without cooling the turbo bearing and oil,
the oil undergoes heat soak, a long period of exposure to very high
heat. Heat soak is extremely harmful to oil. The more volatile
portions of the oil boil off and what oil is left oxidizes to form a
crusty layer inside the turbocharger. This crust will eventually
flake off, wedge between close-fitting components in the
turbocharger, and grind and gouge surfaces, altering clearances and
generating more abrasive debris. Eventually, this condition leads to
the total destruction of the turbocharger, requiring costly repair
or replacement.
To combat these problems, a turbo oil of API service classification
"CF" is required. API CF turbo oils should have high quality VI
Improvers, so there won't be a breakdown in viscosity performance.
CF oils specify higher detergent levels to help keep the engine free
of carbon build-up and deposit formation. In addition, increased
levels of anti-oxidants protect the engine from oxidation and
corrosion problems.
SJ-CF oils are appropriate for use in turbocharged gasoline engines.
They are not appropriate for use in diesel engines, though the "CF"
may make it appear so.
The API Service Category designation for diesel engine oils begins
with the "C" listing, for example, CH-4, SH. Because fleets often
simplify maintenance practices by allowing use of one oil for all
fleet vehicles, diesel engine oils are sometimes formulated for use
in gasoline engines. Such oils earn a designation such as CH-4, SH.
Such oils provide adequate performance in gasoline engines though
they are primarily formulated for use in heavyduty diesels.
On the other hand, most gasoline engine oils are used in non-fleet
vehicles so they are not required to pull "double duty" as both
gasoline and diesel engine lubricants. They are not formulated with
the special needs of heavy-duty diesel engines in mind. Oils whose
API Service Category begins with an "S" listing are meant for use in
gasoline engines only. The "CF" in the SH, CF designation indicates
sufficient detergency and oxidation protection for turbo-charged
gasoline engines.
Always follow recommended SAE and API standards in your engine
owner's manual to be assured of proper protection for your engine.
The Importance of Engine Filtration and
Maintenance
Engine Wear
Automotive experts agree that dirt is the number one cause of engine
wear. Federal-Mogul Corporation, in analyzing the cause of engine
bearing failure, indicates that 43.4 percent of all engine bearing
distress is caused by dirt.
Engine dirt particles are so small -mere dust specks - and an engine
is a highly sophisticated piece of machinery,
crafted from the most durable metal alloys. How can these minute
particles bring down such a high-tech giant?
The answer lies in the fact that dirt particles are extremely
abrasive. They consist of razor-like flakes of road dust and
airborne grit drawn into the engine through the intake.
manifold, as well as manufacturing scarf and wear metal particles
generated inside the engine. These particles are carried by the oil
into the precision clearances between bearings and other moving
parts. Once they work in between these parts, they grind and gouge
surfaces, altering clearances and generating more abrasive debris.
As this wear cycle continues, precision components become sloppy and
fatigued. Finally, they fail altogether.
Filtration is the key to preventing costly repairs caused by engine
dirt. Filtration removes contaminants by trapping and holding them
outside the system of oil circulation. In order for a filter to be
truly effective, it must be able to capture contaminants of all
types and sizes. AMSOIL has developed a complete line of
sophisticated filtration products designed to offer the best
protection available against virtually all harmful engine
contaminants.
Air Filtration
An engine "breathes" air to mix with fuel for combustion - about
9,000 gallons of air for every one gallon of gas. And there is a lot
more dust and grit in the air than is generally realized - over 400
tons of suspended dirt in a cubic mile of air over a typical city,
and the concentration can be much higher in rural areas where there
is frequent travel over unpaved roads.
The air filter is the first line of defense against the abrasive
airborne grit that can cause serious damage inside an engine. But in
order to do the job right, an air filter must effectively filter the
dangerous particles out of the incoming air without obstructing the
vital flow of air that sustains the engine.
Conventional air filters use pleated paper as the filter media. The
paper surface quickly becomes obstructed with dirt, reducing engine
air intake. Inadequate air intake inhibits combustion, leading to
poor engine performance and low fuel efficiency.
 AMSOIL
uses thick layers of polyurethane foam in its 2-Stage Air Filter
construction. This foam is wetted with a light coating of "tack"
oil. As air is drawn through the honeycomb network of oiled fibers,
dirt particles are trapped by the oil and only clean air emerges
from the foam and passes into the engine.
Because the foam is much thicker than paper, the filtering area is
more spread out and air is able to pass through it easily and
quickly.
The Last Air Filter Your Car Will Ever
Need
The AMSOIL 2-Stage Foam Air Filters are designed to last
indefinitely with proper service. Under normal driving conditions
they may be used for 25,000 miles or one year, then cleaned, reoiled,
reinstalled and used again for thousands of additional miles of
trouble-free service.
When a paper filter is full of dirt, the only option you have is to
throw it away and replace it with a new one. This can be costly over
several years because recommended change intervals can be relatively
short depending on driving conditions.
Oil Filtration
 Full-flow
oil filters install directly into the line of oil circulation. The "fullflow"
of oil passes through the filter as the oil journeys between the oil
pump and the engine.
A full-flow filter must be capable of removing and holding
contaminants without obstructing oil flow to the engine. In order to
achieve this, most filters on the market compromise the filtration
of finer particles by using a thin layer of porous filter paper. In
addition, these filters have almost no extended cleaning ability
since they have a low capacity for storing dirt.
These "surface-type" paper filters quickly become restricted as
debris builds up on the paper surface. When this happens, the filter
by-pass valve opens and the filter begins to allow unfiltered oil
into the engine.
The
AMSOIL SDF Engine Oil Filter is composed of a special cellulose,
synthetic and glass blend media to provide longer life and improved
efficiency. Performance tests demonstrated that AMSOIL SDF Filters
provide up to 100 percent more capacity than other leading filters.
They also achieve nearly 95 percent operating efficiency,
outperforming all major brands. An oil pressure relief valve assures
proper oil flow at all times under all operating conditions. Each
heavy-duty case has a drawn steel double-crimp at the base with
rolled-under seaming. An anti-drain back valve keeps dirty oil in
the filter when the engine is not running.
By-Pass Oil Filtration
An
average full flow filter traps particles as small as 20 microns. The
filter cannot remove finer particles because
the oil must be filtered quickly while removing most of the
particles present in the oil.
However, particles in the 5 to 20 micron range cause up to 60% of
all engine wear. The AMSOIL By-Pass Oil Filter traps particles in
the 5 to 20 micron range. In fact, the AMSOIL By-Pass Oil Filter
traps particles smaller than 1 micron.
Unlike the full-flow filter, a bypass filter is situated outside the
main line of oil circulation. The bypass filter taps into the main
line, bleeding off and cleaning only a portion of the oil at any one
time. The by-pass filter retains the oil longer and does a thorough
job of removing contaminants without the worry of obstructing oil
circulation.
The AMSOIL By-Pass Filter traps particles smaller than one micron in
diameter, leaving oil analytically clean and free from harmful dirt
particles. And even though the AMSOIL By-Pass Filter only draws
about 10% of the oil in the system at one time, it will filter all
the oil in a six-quart system in about five minutes (at an engine
speed equivalent to 45 miles per hour).
Water Removal
 Engines
accumulate water from intake air and from fuel combustion. Water
promotes rust and corrosion in engines. Water also reacts with oil
additives and reduces additive effectiveness. Water is particularly
harmful in cars that are not driven often.
The unique composition of the AMSOIL By-Pass filtering media allows
for the removal of water from the engine oil. Even water that has
been thoroughly churned into the oil by mechanical agitation is
separated and safely stored in the cartridge, or filter element,
eliminating the risk of oil degradation and engine rust and
corrosion.
Reduces Oil Changes
By cleaning the oil so completely, the AMSOIL By-Pass Oil Filter
prolongs not only engine life but also the life of
the oil itself. With the AMSOIL By-Pass Oil Filter, oil changes can
be extended well beyond normal, in many cases indefinitely,
depending upon the conditions and severity of use.
Dual Remote: Patented Protection
Available only from AMSOIL, the Dual Remote Oil Filtration System
replaces your conventional full flow filter, mounting in any
convenient location in your engine, and gives you full flow and
bypass oil filter protection. With Dual Remote, filter changes are
quick, clean and easy. And Dual Remote increases your engine's oil
capacity, helping your oil work better, not harder.
Oil Analysis
By analyzing used engine oil, a qualified lab can determine the
degree of protection the oil is delivering and make certain the oil
has not been contaminated. Oil analysis can also detect impending
engine failure.
The
AMSOIL TRIGARD Plan offers motorists AMSOIL Synthetic Motor Oil,
AMSOIL Oil and Air Filters and oil analysis for their personal
vehicles, such as passenger cars or motorhomes. The AMSOIL G-1318
and G-1451 offer oil analysis for heavy duty diesel engines in
commercial use. They may also be used for passenger car oil
analysis. Oil analysis helps motorists derive the longest life from
their AMSOIL Synthetic Motor Oil and from their engine.
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