Agricultural Engineering Department
motor oil, sae, api, oil classification
Knowledge of different types and classifications of crankcase oils means savings when selecting motor lubricants. In many cases farmers take recommendations of dealers and salesmen when buying oils, because of confusion on types and grades, different engines and conditions under which engines operate.
Crankcase oils perform four main functions in internal combustion engines. They are:
I. Lubricating- this is accomplished by forming a protective film between bearing surfaces to prevent metal to metal contact. Friction and abrasive wear is reduced.
2. Sealing - oil forms a seal between piston, rings and cylinder wall to prevent loss of power and crankcase contamination.
3. Cooling - oil helps to carry away a large amount of heat produced in the engine.
4. Cleaning - oil aids in keeping engines clean by holding impurities or sediments in suspension and reducing deposit formation.
Some other functions include: reducing noise, cushioning shock, and protection of parts. How well these functions are performed depends on type and quality of oil used in the engine.
South Dakota State State College of Agriculture and Mechanic Arts, Agricultural Experiment Station
Waelti, H. and Moe, D. L., "Selection of Motor Oil" (1964). Agricultural Experiment Station Circulars. 189.