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 orders for automotive technicians are the most popular?
With the increasing number of cars is also increasing demand for services such as servicing cars. During the maintenance staff of people working on this, that our car was comprehensively tested in every respect. Even the slightest defect can in fact cause considerable danger on the road. The most common services they perform service technicians working in garages are primarily replacement car parts and ongoing maintenance. Sometimes there is a need to leave the car for a few days in the workshop in order to accurately and precisely mount the data elements or remedy the fault. In such cases, we can often expect us to provide transport from the service centers.
Which parts of the car are the most sought after by car owners?
Once you reach the most automotive parts, car owners? As it turns out, depending on the car model and age there are different needs. Of course, there is also a lot of auto parts that are purchased by all drivers, regardless of the purchased car. Such parts include, inter alia, season tires, wiper accessory which can quickly wear and other similar elements. Depending on the needs of the driver can also invest in tuning parts for cars and installing a few such elements will make our car will become a specific character. Popular, such as auto parts, which can increase the comfort of the passenger.