The design of the oil pump is shown in Figure 5.17.
Oil pump type «Duocentic» with trochoidal gearing driven by the crankshaft through a chain drive. Installed in the engine sump, it takes oil from the sump with an oil receiver and pumps it through a full-flow oil filter into the engine oil pressure line. The oil filter is mounted on the pump frame and connected to the main line.
After the oil filter, a pressure reducing valve is installed, which, when the pressure rises above the set value, dumps excess oil into the oil bath (pallet). If the filter is clogged, the bypass valve directs the unfiltered oil directly into the pressure line. The opening pressure of the reducing valve is 4.5 kgf/cm2. The range of pressure adjustment on the engine, warmed up to operating temperature, is 4.0 - 6.0 kgf / cm2.
A non-return valve is installed in the oil filter fitting, which prevents oil from flowing out of the channels and hydraulic compensators of the valve drive after the engine is stopped. The purified oil flows through the pressure line and its branches to the main bearings of the crankshaft. Through inclined drillings in the body of the crankshaft, oil enters its connecting rod journals and sprays to the piston pins and cylinder mirrors. At the same time, engine oil through vertical channels enters the cylinder head to the camshaft bearings, cylindrical valve lifters, valve guides, chain tensioners and the mechanism for changing the position of the intake valve drive shaft.