The lubrication system is combined, with oil supply to rubbing surfaces under pressure and splashing and automatic oil temperature control with a thermal valve

Hydraulic valve lifters and chain tensioners are lubricated and function under oil pressure.

The lubrication system includes: oil sump, oil pump with suction pipe and pressure reducing valve, oil pump drive, oil channels in the cylinder block, cylinder head and crankshaft, full-flow oil filter, oil dip stick, thermal valve, oil filler cap, oil drain plug and oil pressure sensors.

Oil circulation is as follows.

Pump 1 sucks oil from crankcase 2 and brings it through the channel of the cylinder block to thermal valve 4.

ZMZ-406 engine lubrication system

At an oil pressure of 4.6 kgf / cm2, the pressure reducing valve 3 of the oil pump opens and the oil is bypassed back into the suction area of ​​the pump, thereby reducing the pressure increase in the lubrication system.

The maximum oil pressure in the lubrication system is 6.0 kgf/cm2.

When the oil pressure is above 0.7 ... 0.9 kgf/cm2 and the temperature is above plus 81 + 2°C, the thermal valve starts to open the passage for the oil flow to the radiator, which is discharged through the fitting 9.

The temperature of the full opening of the thermal valve channel is plus 109 + 5 ° С. The cooled oil from the radiator returns to the oil sump through hole 22. After the thermal valve, the oil enters the full-flow oil filter 6.

The purified oil from the filter enters the central oil line 4 of the cylinder block, from where it is supplied through channels 18 to the crankshaft main bearings, through channels 8 to the intermediate shaft bearings, through channel 7 to the upper bearing of the oil pump drive shaft and is also supplied to the hydraulic tensioner of the lower camshaft drive chain.

From the main bearings, oil is supplied through the internal channels 19 of the crankshaft 20 to the connecting rod bearings and from them through the channels 17 in the connecting rods is supplied to lubricate the piston pins.

To cool the piston, oil is sprayed onto the piston head through a hole in the upper head of the connecting rod.

From the upper bearing of the oil pump drive roller, oil is supplied through the transverse drillings and the inner cavity of the roller to lubricate the lower roller bearing and the bearing surface of the driven gear of the drive.

The oil pump drive gears are lubricated by a jet of oil sprayed through a hole in the central oil line.

From the central oil line, oil through channel 10 of the cylinder block enters the cylinder head, where it is supplied through channels 12 to the camshaft bearings, through channels 14 to the hydraulic pushers, through channel 11 to the hydraulic tensioner of the upper camshaft drive chain.

Following from the gaps and flowing into the oil sump at the front of the cylinder head, oil enters the chains, tensioner levers and camshaft sprockets.

At the rear of the cylinder head, oil flows into the oil sump through the head opening through the hole in the cylinder block boss.

Filling oil into the engine is carried out through the oil filler pipe of the valve cover, closed by cover 13 with a sealing rubber gasket.

The oil level is controlled by the marks on the oil level indicator 21: the upper level - “MAX” and the lower one - “MIN”.

Oil is drained through a hole in the oil sump, closed by a drain plug 23 with a seal.

Oil cleaning is carried out by a mesh installed on the oil pump intake coupler, by filter elements of a full-flow oil filter, as well as by centrifugation in the crankshaft channels.

Oil pressure is controlled by an emergency oil pressure indicator (control lamp on the instrument panel), sensor 16 of which is installed in the cylinder head.

The emergency oil pressure indicator lights up when the oil pressure drops below 40.. .80 kPa (0.4.. .0.8 kgf/cm2).

Oil pump - gear type, installed inside the oil sump, fastened with a gasket with two bolts to the cylinder block and a holder to the third main bearing cap.

ZMZ-406 engine lubrication system

The drive gear 1 is fixedly fixed on the shaft 3 with a pin, and the driven gear 5 rotates freely on the axis 4 pressed into the pump housing 2.

At the upper end of roller 3, a hexagonal hole is made, into which the hexagonal shaft of the oil pump drive enters.

Centering the pump drive shaftIt is achieved by fitting the cylindrical protrusion of the pump housing into the bore of the cylinder block.

Pump housing is cast from aluminum alloy, baffle 6 and gears are made from sintered metal.

A intake pipe 7 cast from aluminum alloy with a grid, in which a pressure reducing valve is installed, is attached to the body with three screws.

Reducing valve - plunger type, located in the oil pump intake pipe. The valve plunger is made of steel, to increase the hardness and wear resistance of the outer working surface, it is subjected to nitrocarburizing.

ZMZ-406 engine lubrication system

The pressure reducing valve is adjusted at the factory by selecting washers 3 of a certain thickness. It is not recommended to change the valve setting in operation.

Oil pump drive - is carried out by a pair of helical gears from the intermediate shaft 1 of the camshaft drive.

ZMZ-406 engine lubrication system

On the intermediate shaft, with the help of a segment key 3, the drive gear 2 is installed and secured with a flange nut.

The driven gear 7 is pressed onto the roller 8, which rotates in the bores of the cylinder block.

A steel bushing 6 with an internal hexagonal hole is pressed into the upper part of the driven gear.

A hexagonal shaft 9 is inserted into the hole of the bushing, the lower end of which enters the hexagonal hole of the oil pump shaft.

The oil pump drive is closed from above by cover 4, fixed through gasket 5 with four bolts.

The driven gear is pressed against the drive cover during rotation by the upper end surface.

The drive and driven helical gears are made of ductile iron and nitrided for improved wear resistance.

Hexagonal roller is made of alloy steel and carbon nitrided. Drive roller 8 steel, with local hardening of the supporting surfaces by high-frequency currents.

Oil filter - full-flow single-use oil filters of a non-separable design are installed on the engine.

Filters 2101С-1012005-NK-2 and 406.1012005-02 are equipped with a bypass valve filter element, which reduces the likelihood of untreated oil entering the lubrication system when starting a cold engine and limiting contamination of the main filter element.

ZMZ-406 engine lubrication system

Oil cleaning filters 2101С-1012005-NK-2 and 406.1012005-02 work as follows: oil is supplied under pressure through the holes in the cover 7 into the cavity between the outer surface of the main filter element 5 and the housing 2, passes through the filter curtain element 5, is cleaned and enters through the central hole of the cover 7 into the central oil line.

When the main filter element is extremely dirty or a cold start, when the oil is very thick and difficult to pass through the main filter element, the bypass valve 4 opens and the oil passes into the engine, being cleaned by the filter element 3 of the bypass valve.

Anti-drainage valve 6 prevents oil from flowing out of the filter when the car is parked and subsequent "oil starvation" when starting.

Filter 406.1012005-01 is designed similarly to the oil filters presented above, but does not contain filter element 3 of the bypass valve.

The oil filter must be replaced at TO-1 (every 10,000 km of run) simultaneously with the oil change.

Thermal valve — designed for automatic flow control

oil into the oil cooler depending on the temperature of the oil and its pressure. On the engine, a thermal valve is installed between the cylinder block and the oil filter.

ZMZ-406 engine lubrication system

The thermal valve consists of a housing 3, cast from an aluminum alloy, two valves: a safety valve, consisting of a ball 4 and a spring 5, and a bypass valve, consisting of a plunger 1 controlled by a thermal force sensor 2, and a spring 10; threaded plugs 7 and 8 with gaskets 6 and 9. The hose for supplying oil to the radiator is connected to fitting 11.

From the oil pump, oil is supplied under pressure to the cavity of thermal valve A. When the oil pressure is higher than 0.7... 0.9 kgf/cm the ball valve opens and the oil enters the channel of the body of the thermal valve B to the plunger 1.

When the oil temperature reaches 81 ± 2°C, the piston of the thermal force element 2, washed by the flow of hot oil, starts to move the plunger 10, opening the way for the oil flow from channel B to oil cooler.

The ball valve protects the rubbing parts of the engine from an excessive drop in oil pressure in the lubrication system.

Checking the thermal valve can be found in the article - How to check the ZMZ-405 engine oil supply thermal valve