One of the biggest misconceptions about oil pumps centers around oil pressure.

As this video from Melling explains, oil pumps don’t produce oil pressure. They flow a particular volume of oil, which is then regulated by a valve within the pump. This valve determines the maximum oil pressure the pump can deliver.

Oil pressure is the byproduct of multiple factors that create resistance, including restrictions in the oil passages, the weight of the oil, and critical clearances within the engine. According to Melling, bearing clearances have, by far, the biggest effect on oil pressure. Check out the video below for a nifty demonstration of how the main bearing clearances affect oil pressure.

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Author: David Fuller

David Fuller is OnAllCylinders' managing editor. During his 20-year career in the auto industry, he has covered a variety of races, shows, and industry events and has authored articles for multiple magazines. He has also partnered with mainstream and trade publications on a wide range of editorial projects. In 2012, he helped establish OnAllCylinders, where he enjoys covering all facets of hot rodding and racing.