Prelube pumps move oil from the oil sump to the moving parts of an engine before engine start-up. Prelubing before every start is an inexpensive way to extend the life of engine- driven equipment. When an engine is running, the engine's oil pump supplies pressurised oil into the centre of the bearings to create a cushion that separates the bearing surface from the crankshaft.
Once the engine is running, the surfaces never touch because they ride on this film of oil. As soon as the engine shuts down, however, the oil that comprises the cushion begins to drain away and the film thins. After only a few seconds, the film thins to the point that “metal- to-metal” contact can begin to occur. In other words, the cushion is gone and the crankshaft is resting directly on the bearing.
Prelubing the engine before every engine start offers a way to extend engine life by eliminating metal- to-metal contact during the first several seconds of running. Those few seconds after cranking the engine can be suspenseful for the operator as the oil pressure rises. If the engine has been sitting for extended periods, it can take an uncomfortable amount of time for oil pressure to come up. Without oil, the engine will not last long.
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It's common knowledge that the vast majority of total engine wear occurs during these few brief seconds. A pre- lube system can eliminate this engine start-up wear and extend Mean Time Between Critical Failures (MTBCF) and the overhaul interval.
Prelube systems can cost between $600 and $3000 per engine to fully implement. The cost is justified by the expectation of extending the useful life of an expensive engine. The financial breakeven point with prelube is generally less than 2% percent reduction in wear. With wear reduction rates are commonly as high as 40%. Prelube can be profitable for engines where how long the engine lasts determines the useful life of the product.
Prelube is common in industries such as
- Power generation
- Oil and gas compressors
- Locomotive primary power
- and marine power
For further information email: pumps@ese.tc
