Filter out too little, and engine wear will increase. While base oil does not actually wear out, the various additives in the oil can become depleted. And when the additives are gone, the oil will no longer perform effectively. Filters play an important role in how long you can count on your oil to do its job. Proper filtering prevents a buildup of contaminants that can score bearings, rings and cylinder walls.
Contamination also can contribute to an increase in viscosity and gum deposits on rings and valves.
Because filtration is necessary for effective engine protection, it is important to make sure you have the best available system in good working order. Wear is caused by having particles of dirt suspended in the oil that are bigger than the film of oil between moving parts when the equipment is under load. It is called a bypass because the oil it filters flows back to the sump, bypassing the engine itself. The amount of flow through a bypass filter is controlled by an orifice in the system which is sized to get a flow of approximately 10 percent of the total pump output. The T.F. Hudgins Company, the firm that manufactures the Spinner II bypass filter, has prepared this outline of the various bypass systems available to fleets.