Engine Oiling System
Engine utilizes a wet sump oil system. An oil cooler is located in a housing on engine and uses coolant as a heat exchanger. Cooler housing is also used as an oil filter and oil pressure sending unit mount. The oil pump is a crescent gear type pump located in a separate housing that is bolted to front of crankcase.
An oil pressure relief valve is located inside the oil pump housing. A splined drive sleeve drives oil pump by way of an axial connection with the inner gear. Oil pump draws in oil from oil pan through oil filter screen. See Fig 1. Filter screen tube is mounted on crankcase lower section and is sealed with an "O" ring. Oil continues to oil pump through a suction bore in crankcase upper and lower sections.
Sealing surfaces around suction bore are coated with sealant (Loctite 574). Oil delivered by pump enters a short bore in crankcase upper section. From there, oil reaches pressure relief valve and oil cooler. After being cooled, oil passes through oil filter and pressure sending unit and enters main bore. Main bearings are supplied by main oil bore. Connecting rod bearings receive oil from crankshaft.
Oil for left balance shaft rear bearing comes from crankshaft thrust bearing (No. 3). Right balance shaft is supplied by a separate bore off of main bore. An oil bore in each balance shaft supplies oil to front flange bearings
A gallery passes through crankcase to cylinder head and camshaft housing. Camshaft housing has branching bore to supply oil to camshaft and lifters. A check valve is installed to prevent oil from flowing down cam supply bore when engine is not operating.