A dry sump is a lubricating motor oil management method for four-stroke and large two-stroke piston internal combustion engines that uses additional pumps and a secondary reservoir for oil, as compared to a conventional wet sump system, which uses only the main sump (U.S.: oil pan) below the engine and a single pump. A dry sump can also be implemented with a single vacuum pump that creates positive and negative pressures to pull and push the oil out and into the engine.