This pump is run by the spiral gear built on the cam shaft. It is fitted in the oil-chamber so that its filter screen remains dipped in the oil. It has two gears. First gear, whose shaft remains out of the pump, works by camshaft and the second gear works with the first gear. A very small gap remains between the two gears. The oil reaches the pump through inlet passage and by pressure of the second gear, oil reaches in the main oil gallery through outlet . passage.