OIL DRAINBACK SYSTEM FOR INTERNAL COMBUSTION ENGINE

摘要

An internal combustion engine having an oil drainback passage and integral check valve. The oil drainback passage allows the flow of oil from the valve box to the crankcase of the engine during normal operation and prevents the backwards flow of oil from the crankcase to the valve box when high pressures exist in the crankcase or if the engine is operated at elevated angles. The oil drainback passage is formed by a bore through a cylinder wall of the crankcase and a bore through the cylinder head.