What is the difference between an automotive and a marine engine?
The duty cycles differs for automotive and marine engines. Marine engines run at a higher RPM for an extended period of time. Because of this, the valve train, including valves and springs, is different for a marine engine than for that of an engine used in an automotive application. Marine engines also use brass freeze plugs and head gaskets with stainless steel fire rings (unless unavailable for specific applications) to resist the effects of corrosion from the engine cooling system. Because boats operate on ever-changing water surface conditions, the oiling systems of their engines needs to be able to minimize the “sloshing” of the oil and a resulting irregular supply of oil at the pick-up tube in the oil pan. For this reason, marine engines use a more elaborate baffle system in the oil pan to keep oil levels more consistent in order to maintain a steady supply of oil to the various engine components.