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7/31/2019 Amsoil Filter
7/31/2019 Amsoil Filter
2 MOTOR OIL AND FILTRATION GUIDE
Motor oil is the primary determinantin the durability of an engine. It con-tains two basic components: basestocks and additives.
The base stock is the bulk of the oil.The base stock lubricates internalmoving parts, removes heat andseals piston rings.
Motor oil base stocks can bemade from: 1) petroleum, 2) chem-ically synthesized materials, 3) acombination of synthetics and petro-leum (called para-synthetic, semi-synthetic or synthetic blend.)
A petroleum base stock consistsof many different oil fractions thatform the final product. Generally,
molecules of a petroleum base stockare long carbon chains that can besensitive to the stress of heat andboil off at relatively low tempera-tures. Engine temperatures breakdown these molecular chains,changing the physical properties(such as viscosity) of the motor oil.
The difference with synthetic basestocks is that molecules are uni-formly shaped, which makes themmore resistant to the stress of heat.Because AMSOIL synthetic motor
oils possess these uniformly-shapedmolecules, they have a low boil offrate. Thus, their physical properties(such as viscosity) do not change.
The various chemicals that comprisethe additive system in motor oilsfunction to provide anti-wear, anti-foam, corrosion protection, acid neu-tralization, maintenance of viscosity,detergency and dispersancy. Theseare the chemicals that help modernmotor oils meet the increasing
demands of todays high-techengines. Their quality varies widelythroughout the lubrication industry,ranging from a bare minimum insome oils (to comply with certainrequirements) to exceptionally highquality, as in all AMSOIL motor oils.
What a Motor Oil Must Do
Modern motor oil is a highly special-ized product carefully developed byengineers and chemists to perform
many essential functions. A motoroil must:
Permit easy starting Lubricate engine parts and
Reduce friction Protect against rust and
corrosion Keep engine parts clean
Minimize combustionchamber deposits
Cool engine parts Seal combustion pressures
Aid fuel economy.
Improvements in Oil
The quality of motor oil has changeddramatically in the past 30 years,and new demands on lubricants inmodern engine design call for oilsthat meet stringent requirements.Variations in an oils ability to meetthe requirements determine whichservice classification rating andviscosity grade it receives.
Service classifications are deter-mined by the American PetroleumInstitute. Viscosity grades of oils aredetermined by the Society of Auto-motive Engineers. These two organ-
izations have set industry standardsfor motor oils for more than 75 years.
Viscosity, the most important prop-erty of an oil, refers to the oils resist-ance to flow. The viscosity of oilvaries with changes in temperature thinner when hot, thicker whencold. An oil must be able to flow atcold temperatures to lubricate inter-nal moving parts upon starting theengine. It must also remain viscous
or thick enough to protect anengine at high operating tempera-tures. When an oil is used at avariety of temperatures, as it is inmost engines, the change of vis-cosity with temperature variationshould be as small as possible.
The measure of an oils viscositychange is called theViscosity Indexnumber (VI); the higher the number,the smaller the viscosity changewhich means the better the oil pro-
tects the engine. The number doesnot indicate the actual viscosity inhigh and low temperature extremesof the oil. It represents the rate of vis-cosity change with temperaturechange.
Viscosity improvers are viscouschemical compounds called poly-mers or polymeric compounds thatdecrease the rate at which oils
change viscosity with temperature.These viscosity modifiers extend amotor oils operating temperaturerange and make multi-grade or all-season oils possible. However, low-quality viscosity improvers lendthemselves to shearing.
The VI is measured by comparingthe viscosity of the oil at 40C(104F) with its viscosity at 100C(212F). VI can provide insight intoan oils ability to perform at high andlow temperatures.
Petroleum-based motor oils requirethe use of viscosity improvers tomeet the low-temperature require-ments of SAE 0W, 5W or 10W andthe high-temperature requirementsof SAE 30 or heavier oil.
Synthetic-based motor oils havea naturally-high viscosity index andrequire less viscosity improver addi-tive than petroleum oils.
What Is a Motor Oil?
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 100
SAE Viscosity Grade andOutdoor Temperature
7/31/2019 Amsoil Filter
MOTOR OIL AND FILTRATION GUIDE 3
Motor oil must begin to circulateas soon as the engine is started. Ifoil gets cold enough and beginsto solidify, it fails to flow through
the oil screen to the pump at enginestart and causes bearings andother critical parts to fail almostimmediately.
Pour point is an indicator of theability of an oil to flow at cold operat-ing temperatures. It is the lowest tem-perature at which the fluid will flow.
Modern refining techniques removemost of the wax from petroleum oil,but some wax-like molecules remain.These wax-like molecules are solubleat ambient temperatures above freez-ing, but crystallize into a honeycomb-like structure at lower temperaturesand cause oil circulation problems.
Pour point depressants keepwax crystals in the oil microscopi-cally small and prevent them fromjoining together to form the honey-comb-like structure. They lower thetemperature at which oil will pour orflow and are found in most motoroils designed for cold-weather use. Assynthetic motor oils do not containthose wax crystals, they do not requirepour point depressant additives.
Since one of an oils main functions isto prevent friction and wear,anti-wearadditives are part of the chemicalcomposition of an oil. These additivesprotect engines by bonding to metalsurfaces and forming a protective filmlayer between moving parts that arevulnerable to friction and wear whenan engine is first started and before theoil begins to circulate completely. Whilethis protective film doesnt entirely elim-inate metal-to-metal contact of moving
parts at start-up, it minimizes theeffects of contact.
Because excessive engine heatcauses chemical breakdown of oil,which in turn results in permanentthickening of the oil, oxidationinhibitors work to limit the impactof oxidation. Oil oxidation producesacidic gases and sludge in thecrankcase. These gases combine with
water in the crankcase to corrodeand rust the engine. Corrosionprevention is especially critical indiesel engines.
An oils ability to neutralize acids isexpressed by its Total BaseNumber (TBN). The greater thenumber, the greater the amount ofacidic by-products the oil can neu-tralize. A high TBN is particularlyimportant in extended drain intervaloils, such as AMSOIL motor oils,because they neutralize acids, andmore of them, for a longer period oftime.
Most oils for diesel engines inNorth America have a TBN between
8 and 12. AMSOIL manufacturesseveral diesel oils with a TBN of 12.
In the same way that some chemicalcompounds are used to preventengine rust and corrosion, other chem-icals are added to motor oil to helpprevent combustion by-products fromforming harmful sludge or varnishdeposits. Detergents are added tomotor oil because combustion causescarbon build-up and deposit forma-
tion on the pistons, rings, valves andcylinder walls. Carbon and depositsaffect engine temperature, oil circula-tion, engine performance and fuel effi-ciency. Detergent additives clean theseby-products from the oil. Some com-bustion by-products slip past the pistonrings and end up in the motor oil, whichcan clog the engines oil channels.
While detergents help minimize theamount of combustion by-products,dispersant additives keep those by-
products suspended in a form sofine they minimize deposits. Theykeep the oil in the engine clean whilethey prevent the build-up of carbonor deposits from burned andunburned fuel and even from the oilitself. Eventually, these suspendedparticles are removed by the oil filter.
The addition of silicone or other com-pounds in very small amounts makes
most oils adequately foam-resistant.Its important to minimize foaming inmotor oil because tiny air bubbles arewhipped into motor oil by the action ofmany rapidly moving parts, resulting
in a mass of oily froth that has very littleability to lubricate or aid in the coolingof the engine. These compoundsweaken the air bubbles, causing themto collapse almost immediately uponforming, allowing the oil to continue toprotect the engine.
All motor oils must be compatiblewith the various seal materials usedin engines. Oil must not cause sealsto shrink, crack, degrade or dis-solve. Ideally, oils should cause
seals to expand or swell slightly toensure continued proper sealing.
Another function of motor oil is tocool the engine. The radiator/anti-freeze system is responsible forabout 60 percent of the engine cool-ing that takes place. This cools onlythe upper portion of the engine,including the cylinder heads, cylin-der walls and valves.
The other 40 percent is cooledby the oil. The oil is directed ontohot surfaces, such as the crankshaft,main and connecting rod bearings,the camshaft and its b