Engine lubrication system

The engine lubrication system is designed to supply oil to rubbing surfaces in order to reduce friction and increase the mechanical efficiency of the engine, reduce wear of rubbing parts, cool them and purify the oil from mechanical and other harmful impurities.

Lubrication of rubbing parts, along with the selection of materials and the type of treatment of their surfaces, effectively increases the durability of the engine. Purification of the circulating oil from mechanical and other harmful impurities is provided by an oil filter with a paper filter element.

Engine oil has a complex of additives that provide high lubricating properties of the oil, resistance to oxidation and the ability to work in a wide temperature range.

The oil reserve necessary for normal operation of the engine is located directly in the crankcase. Oil is filled into the engine crankcase through the oil filler neck, hermetically sealed with cover 20. The oil level is controlled by the marks on the oil level indicator 35. Waste oil is drained from the system through a hole closed with a threaded drain plug 7. The capacity of the oil system is 2.5 liters.

The lubrication system of the engine is combined, in which part of the parts is lubricated under pressure, part by gravity and part by spraying.

Under pressure, the main and connecting rod bearings of the crankshaft, the bearings of the distribution hall are lubricated.

Oil flowing from the gaps and splashed by moving parts lubricates the cylinder walls, pistons with piston rings, piston pins in the piston bosses, camshaft cams, balance shaft bearings and gears for their drive, valve lifters, and valve stems in their guide bushings.


The lubrication system includes an oil sump, a 26 oil receiver with a filter mesh, an oil pump and a pressure reducing valve 1, a system of oil channels 4, 6, 11, 12, 15 in the block and 16 in the cylinder head, crankshaft and camshafts, a full-flow oil cleaning filter with a filter element 8. bypass valve 9 and anti-drainage valve 10, oil level indicator 35 and oil filler neck with cap 20.

The minimum oil pressure is monitored by sensor 5 of the oil pressure warning lamp. The sensor is screwed into the hole of the oil filter flange, connected by channels 4 and 6 through the filter cavity with the main oil line 12 in the cylinder block. Minimum oil pressure must be at least 0.8 kgf/cm² at 750-800 rpm.

When the oil pressure drops below the permissible value, one of the indicator lamps in the instrument cluster lights up in red.

The circulation of oil during engine operation is as follows. The oil pump, located at the front end of the crankshaft, sucks oil through the filter mesh of the oil receiver 26, the suction tube and the channel in the pump housing and delivers it through the channel 4 in the cylinder block to the full-flow filter. In the filter, the oil is purified from mechanical impurities and resinous substances. The filtered oil through channel 6 enters the main oil line 12, which runs along the cylinder block, and from there it is fed through channels 11 in the partitions of the cylinder block to the crankshaft main bearings. The main bearing shells have two holes through which oil penetrates into the annular grooves on the inner surface of the shells. From these grooves, part of the oil goes to lubricate the main bearings, and the other part through the channels drilled in the necks and cheeks of the crankshaft to the bearings of the lower heads of the connecting rods. Through the side hole 13 in the connecting rod from the connecting rod bearing, a jet of oil enters the cylinder mirror at the moment the bearing hole coincides with the channel in the connecting rod journal. The oil removed from the cylinder walls by the oil scraper ring is discharged through the holes in the piston into the piston and lubricates the piston pin bearings in the piston bosses.


In the connecting rod journals of the crankshaft, centrifugal cleaning of oil from particles of wear products of parts and from foreign inclusions contained in the oil, which accumulate in inclined channels under the action of centrifugal forces in space from the holes in the connecting rod journal to the plug of the oil channel of the crankshaft, also takes place.

In addition, from the main oil line 12, oil is supplied through vertical channels 15 in the block and cylinder head to the oil line 16 of the cylinder head, and from there through channels 17 to the camshaft bearings.

The oil flowing from the camshaft bearings lubricates the working surfaces of the cams and valve lifters.

The oil collected under the cylinder head cover drains to the left side of the engine and drains through the ports in the head and channels in the cylinder block into the crankcase.

The oil pressure on a warm engine at medium speed is 0.35... 0.45 MPa (3.5...4.5 kgf/cm²).

In order to ensure the necessary oil pressure in the line when the engine is running in any mode, as well as to compensate for the oil consumption that increases with engine wear, the oil pump has an excess capacity. And in order to prevent an increase in oil pressure above the permissible level, a pressure reducing valve 1 is installed in the system, which bypasses excess oil back to the oil pump inlet.

Oil pump

The engine oil pump is assembled in a special case 21 attached to the front wall of the cylinder block. The oil pump is single-section with gear wheels of internal gearing.


The oil pump drive gear 2 is mounted on the front end of the crankshaft.

A driven gear wheel 3 is installed in the oil pump housing. To ensure the necessary clearances between the gear wheels and the housing when the temperature changes, the housing is cast from cast iron, the gear wheels are made from cermet. In the housing, the suction cavity is separated from the discharge cavity by a sickle-shaped protrusion.

A pair of gear wheels of the pump rotates in the housing with clearances of 0.03...0.08 mm in height and 0.10...0.17 mm in diameter of the driven gear. The maximum allowable gaps in mating are 0.12... 0.15 mm in height and 0.3 mm in diameter.

When the engine is running, the driving 3 and driven 2 gears of the pump suck in oil and pump it into the discharge cavity of the pump with the cavities of the teeth. At pressures above 4.5 kgf/cm² the pressure reducing valve 1 opens, and part of the oil is bypassed from the pressure cavity into the suction cavity of the pump.

An o-ring 22 is placed under the plug of the pressure reducing valve to prevent oil leakage. The crankshaft in the cover 24 of the oil pump is sealed with an oil seal 23, the oil receiver 26 is sealed with a rubber ring 25.

Oil filter

The oil filter is used to purify the oil from harmful impurities that have a significant impact on the acceleration of engine parts wear. The quality of the oil in the engine does not remain constant, but is clogged with wear products of parts, particles of soot resulting from incomplete combustion in the engine cylinders, and is clogged with resinous substances formed at high temperature of the parts.

The oil filter is screwed onto the flange fitting and pressed against its annular collar. The tightness of the connection is ensured by a rubber gasket installed between the filter cover and the flange shoulder. The oil enters the filter through channel 4 and, having passed the filter element, exits into the main line of the block through the central hole, the mounting fitting and channel 6.

The filter has an anti-drainage valve 10, which prevents oil from draining from the channels of the system when the engine is stopped, and a bypass valve 9, which is activated when the filter element is clogged and bypasses oil, in addition to the filter, into the oil line 12.

The oil is filtered by filter element 8. When changing the engine oil, the filter must be replaced to ensure effective oil filtration.

Engine ventilation system

During engine operation, a certain amount of exhaust gases enter the crankcase through the gaps at the installation sites of the piston rings and the gaps between the valve stems and guide bushings. When starting the engine, gasoline vapors also condense in the cylinders, which, getting into the crankcase, dilute the oil and impair its lubricating properties. The water vapor present in the exhaust gases, condensing in the crankcase, foams the oil and leads to the formation of thick and sticky emulsions, and in combination with sulfur dioxide form acids that corrode the working surfaces of engine parts and accelerate their wear.

To remove gases and gasoline vapors from the crankcase, which increases the service life of the oil and increases the durability of the engine, forced crankcase ventilation is used, which is carried out by sucking gases from the crankcase into the inlet pipe 27 of the engine. In addition, crankcase ventilation prevents pressure build-up in the crankcase due to the ingress of exhaust gases into it. And since the ventilation system is closed, it prevents crankcase gases from entering the car interior and reduces the release of toxic substances into the atmosphere.

Ventilation is carried out by sucking gases from the crankcase through the lower 34 and upper 31 exhaust hoses and hose 29. The oil that is separated in the oil separator flows back into the oil crankcase.