This website is being constructed to provide a meeting place for those who are interested in learning about the many different types and brands of motor oil. From petroleum to synthetic and from AMSOIL to Valvoline.
We may extended this site to include other lubricants such as gear oil, grease, transmission fluid and many others. Also a possibility in the future is the addition of filtration topics.
Use of motor oil
Motor oil is used as a lubricant in various kinds of internal combustion engines in automobiles, boats, lawn mowers, trains, airplanes, etc. In engines there are contacting parts which move against each other at high speeds, often for prolonged periods of time. Such rubbing motion causes friction, absorbing otherwise useful power produced by the motor and converting the energy to useless heat. Friction also wears away the contacting surfaces of those parts, which could lead to lower efficiency and wearing out of the motor.
Lubricating oil makes a film between surfaces of parts moving against each other so as to minimize direct contact between them decreasing friction, wear, and production of excessive heat. Also motor oil carries away heat from moving parts. Materials tend to become softer and less abrasion-resistant at high temperatures. Some engines have an additional oil cooler.
In the crankcase of a vehicle engine, the crankshaft bearings, and big ends of connecting rods are lubricated by pressured oil from an oil pump. Oil squirting from a small hole in the top of the connecting rod lubricates the contacting surfaces between the piston rings and interior surfaces of the cylinders. This oil film also serves as a seal between the piston rings and cylinder walls to separate the combustion chamber in the cylinder head from the crankcase.
Coating metal parts with oil also keeps them from being exposed to oxygen, which inhibits their oxidation at elevated operating temperatures. Corrosion inhibitors may also be added to the motor oil. Many motor oils also have detergent additives to help keep the engine clean and minimize oil sludge buildup.
Rubbing of metal engine parts inevitably produces some microscopic metallic particles from the wearing of the surfaces. Sludge also accumulates in the engine. Such particles could circulate in the oil and grind against the moving parts, causing erosion and wear. Because undesired particles inevitably build up in the oil, the motor oil is circulated through an oil filter to remove harmful particles. The oil pump powered by the engine pumps the oil through the oil filter. Oil filters can be a full flow or bypass type.
Properties of motor oil
Most motor oils are made from a heavier, thicker petroleum hydrocarbon base stock derived from crude oil, with additives added as needed to improve the properties. One of the most important properties of motor oil in maintaining a lubricating film between moving parts is its viscosity. In layman's terms, the viscosity of a liquid can be thought of as its "thickness" or a quantity of resistance to flow. The viscosity must be high enough to maintain a satisfactory lubricating film, but low enough that the oil can flow around the engine parts satisfactorily to keep them well coated under all conditions. The Viscosity Index is a measure of how much the oil's viscosity changes as temperature changes. A higher viscosity index indicates the viscosity changes less with temperature than a lower viscosity index.
Another important property of motor oil is its pour point, which is indicative of the lowest temperature at which the oil could still be poured satisfactorily. The lower the pour point temperature of the oil, the more desirable the oil is when starting up at cold temperature.
Oil is largely composed of hydrocarbons which can burn if ignited. Still another important property of motor oil is its flash point, the lowest temperature at which the oil gives off vapors which can ignite. It is dangerous for the oil in a motor to ignite and burn, so a high flash point is desirable. At a petroleum refinery, fractional distillation to separate crude oil fractions removes the volatile components, which more easily ignite, from the motor oil fraction; thereby increasing the oil's flash point.
Another test done on oil is to determine the Total Base Number (TBN), which is a measurement of the reserve alkalinity of an oil to neutralize acids. The resulting quantity is determined as mg KOH/(gram of lubricant). Similarly, Total Acid Number (TAN) is the measure of a lubricant's acidity. Other tests include zinc, phosphorus, or sulfur content, and testing for excessive foaming.
Sourced from Wikipedia.org
