Most motor oils are made from a heavier, thicker petroleum hydrocarbon base stock derived from crude oil, with additives to improve certain properties. The bulk of a typical motor oil consists of hydrocarbons with between 18 and 34 carbon atoms per molecule.7 One of the most important properties of motor oil in maintaining a lubricating film between moving parts is its viscosity. The viscosity of a liquid can be thought of as its "thickness" or a measure of its resistance to flow. The viscosity must be high enough to maintain a lubricating film, but low enough that the oil can flow around the engine parts 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.
Motor oil must be able to flow adequately at the lowest temperature it is expected to experience in order to minimize metal to metal contact between moving parts upon starting up the engine. The pour point defined first this property of motor oil, as defined by ASTM D97 as "... an index of the lowest temperature of its utility ..." for a given application,8 but the "cold cranking simulator" (CCS, see ASTM D5293-08) and "Mini-Rotary Viscometer" (MRV, see ASTM D3829-02(2007), ASTM D4684-08) are today the properties required in motor oil specs and define the SAE classifications.
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 separates a motor oil fraction from other crude oil fractions, removing the more volatile components, and therefore increasing the oil's flash point (reducing its tendency to burn).
Another manipulated property of motor oil is its Total base number (TBN), which is a measurement of the reserve alkalinity of an oil, meaning its ability to neutralize acids. The resulting quantity is determined as mg KOH/ (gram of lubricant). Analogously, 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.
The NOACK volatility (ASTM D-5800) Test determines the physical evaporation loss of lubricants in high temperature service. A maximum of 14% evaporation loss is allowable to meet API SL and ILSAC GF-3 specifications. Some automotive OEM oil specifications require lower than 10%.
What to remember choosing a car abroad?
Trip by car from abroad can provide a lot of positive emotions. Choosing just a means of transportation, we can afford the time of a little more freedom, so stop in every beautiful and interesting place we meet along the way. But before we go on a trip, please refer to the traffic regulations in force in the countries through which we intend to drive. In addition, we take out appropriate insurance, and above all - thoroughly check the car. This reliable service to guarantee a safe trip without unpleasant surprises. If, before departure, verify the efficiency of all systems and mechanisms, does not surprise us any fault in the way.
Car as a gift for birthdays
Sometimes, as a birthday present bought a car. This applies especially to round birthday, which celebrates particularly close to our person. In choosing an attractive car designed gift can help us staff car showroom, where you want to make the purchase. As part of the gifts we can also perform a review of the car before the first using the vehicle, and thus help a loved person save time that would be spent on driving the car services and we will make it an extra surprise. Knowing her Earning we can also treat it greater amount of engine oil, which will be able to enjoy for a long time.