Two-Stroke Oils

How are two-cycle engines lubricated?

Two-cycle motors are considered total-loss type lubricating systems. Because the crankcase is part of the intake process, it cannot act as an oil sump as is found on four-cycle engines. Lubricating traditional two-cycle engines is done by mixing the oil with the fuel. The oil is burned upon combustion of the air/fuel mixture. Direct Injection engines are different because the fuel is directly injected into the combustion chamber while the oil is injected directly into the crankcase. This process is efficient because the fuel is injected after the exhaust port closes, and therefore more complete combustion of fuel occurs and more power is developed. Direct injection engines have a higher power density than traditional two-cycle engines. Because the oil is directly injected into the crankcase, less oil is necessary and lower oil consumption results (80:1 range). Direct Injection motors have higher combustion temperatures, often up to 120F. They also require more lubricity than traditional two-cycle motors.Shop the AMSOIL online store for our advanced synthetic 2-Stroke oils - specially formulated to provide superior performance, protection and cleanliness properties in a wide variety of 2-stroke applications.