Engine lubrication is accomplished by forced lubrication system using gear pump. The engine oil in the oil pan is drawn up through the oil strainer by the oil pump and force-fed to the oil filter and oil cooler to lubricate all parts.(1) Oil Pump The oil pump, of a gear pump type, is mounted in the rear bottom portion of the crankcase, driven by the crankshaft gear.An oil strainer is mounted at the suction port of the oil pump; an oil pipe at the delivery port.Since the oil pump is driven at speeds proportional to the engine's, the delivery pressure of the oil pump increases during starting in cold weather. A relief valve is built into the oil pump to protect the lubrication system from overpressure.(2) Oil Filter(a) Spin-on type The oil filter is a double oil filter consisting of a full-flow filter made integral with a bypass filter.The element is the spin-on type that is easy to replace. Engine oil passing through the full-flow filter is flows to the oil cooler. Engine oil passing through the upper filter (bypass filter) flows through the oil filter bracket mounting bolt hole to return to the oil pan.The oil filter bracket has the oil bypass alarm mounted whose bypass opens automatically to allow oil before filtering to flow to the oil cooler when the pressure difference across the element exceeds specified level. The oil bypass alarm has electrical contacts that are closed to turn on the warning lamp, warning the driver of clogged element when the valve is opened. As this oil filter is located at relatively high position, it is likely that oil flows down and the oil filter runs short of oil when the engine is stopped. In order to prevent backflow of oil, therefore, a check valve is provided. Also on the bypass side, a bypass check valve that opens only when oil pressure exceeding specified level acts is provided. By this arrangement, the oil level in the filter is always kept constant and quick lubrication of lubricating parts is ensured at time of engine start.(b) Element replaceable type The oil filter is a double oil filter consisting of a full-flow filter made integral with a bypass filter.Engine oil passing through the full-flow filter is flows to the oil cooler. Engine oil passing through the upper filter (bypass filter) flows through the oil filter bracket mounting bolt hole to return to the oil pan.The oil filter bracket has the oil bypass alarm mounted whose bypass opens automatically to allow oil before filtering to flow to the oil cooler when the pressure difference across the element exceeds specified level. The oil bypass alarm has electrical contacts that are closed to turn on the pilot lamp, warning the driver of clogged element when the valve is opened. As this oil filter is located at relatively high position, it is likely that oil flows down and the oil filter runs short of oil when the engine is stopped. At the
