Oil flow pattern (L series engines)
A pressure lubrication system is adopted to supply oil to the moving parts of the engine. The oil from the oil pan is sucked in by the oil pump through the oil receiver. After passing through the oil filter, the oil is supplied through the holes in the crankshaft and cylinder block to the friction pairs. The oil level is checked with a dipstick mounted on the block on the left side.
The oil pump is a trochoidal type gear pump with driving and driven gears. Since the axis of rotation of the drive gear is slightly offset from the center of the driven gear, the gap between the two gears changes during rotation. The oil is sucked in when the gap increases, and is ejected when it decreases.
Reducing valve. At high engine speeds, the amount of oil supplied by the pump exceeds the demand of the engine. The pressure reducing valve is designed to prevent excess oil supply. At normal flow, the coil spring pressure reducing valve keeps the bypass closed, but when excess oil is applied, the pressure in the system builds up against the spring force to open the valve. As a result, excess oil returns to the sump.
Full flow type oil filter with paper filter element. To simplify the replacement of the filter element, the filter is installed outside the engine. A bypass valve is provided in front of the filter element, which opens if the oil filter is clogged. The oil passing through the bypass valve bypasses the oil filter and enters directly into the main oil line of the engine.
Engine 1KZ-T: 1 - piston cooling nozzles, 2 - oil pump, 3 - oil filter, 4 - oil cooler, 5 - oil receiver.