Do-it-yourself yumz tractor engine repair

In detail: do-it-yourself yumz tractor engine repair from a real master for the site my.housecope.com.

The recommendations given in this manual make it possible to carry out routine repairs in such a way that most failures and malfunctions are eliminated directly on the tractor without removing its component parts; only in some cases is it supposed to be removed from the tractor.
Routine repairs are carried out at tractor service stations (STOT), in farm workshops equipped with the necessary equipment, and during busy periods of field work also in farm teams using mobile equipment.

As a rule, current repairs are carried out after in-depth technical diagnostics of the tractor and are combined in time with the third maintenance.

Routine repairs can also be carried out to eliminate failures during operation or when the first or second maintenance was carried out, if during inspection or diagnostics of the tractor it was revealed that any of its component parts cannot work flawlessly until the next scheduled maintenance.
This manual is designed for the application of the aggregate repair method., when individual components and assembly units reach the limit wear and tear, they are replaced with repaired or new ones from the exchange fund. The relevant sections of the manual indicate the conditions under which this component or assembly unit must be replaced. Deviations from the recommended conditions, i.e. Premature replacement of a component or assembly unit is allowed only during intense periods of field work, when a quick restoration of the tractor's performance is dictated by general economic considerations, the need to avoid large losses due to machine downtime.

TECHNICAL CHARACTERISTICS YUMZ-6AKM40

Overall dimensions, mm., Length with hinged system, width, height over the muffler 4063x1884x2830
Clearance: road (under the rear axle), mm 450
Agrotechnical (under the front axle and semiaxis sleeves), 650
Rated traction force, kN (kg) 14 (1400)
Tractor speed, km / h:

forward gear 1.49-32.35
reverse 1.49-7.1
Base, mm 2450 (+ 50-50)
Operating weight (with ballast), kg 3800
Wheel formula 4 × 2
Engine
Model D-242-367
Electric starter start
Accumulator battery 6ST-90A, 2 pcs.
Operating power, kW (hp) 44.1 (60)
Specific fuel consumption, g / kWh (g / e.h.h.) no more than 235 + 3% (172.8 + 3%)
Crankshaft rotation frequency, rpm 1800
Working volume of cylinders, l 4.75
Transmission
Two-flow clutch, dry, frictional with two-speed PTO reduction gear
Mechanical transmission, 10-speed with a reduction gear
Dry disc brakes
Semi-independent power take-off shaft (PTO)
PTO rotation speed, rev / s (rpm) 16.6k (1000) or 9 (540)
Hydraulic system
Type separate-aggregate
Nominal pressure, MPa (kgf / cm2) 16.6 (160)
maximum 20-2 (200-20)
Hydrostatic steering with autonomous power supply
Tires
Front 9.00-20
Rear 15,5R38

TECHNICAL CHARACTERISTICS YUMZ-8040.2

YuMZ-8040.2
Traction class, t. 1.4
Overall dimensions, mm., Length with hinged system, width, height over the muffler 4063x1884x2830

Clearance: road (under the rear axle), mm 450
Agrotechnical (under the front axle and semiaxis sleeves), 650
Rated traction force, kN (kg) 14 (1400)
Tractor speed, km / h:
forward travel 1.52-33.08
reverse 1.53-7.26
Base, mm 2450 (+ 50-50)
Operating weight (with ballast), kg 4100 (+100)
Wheel formula 4 × 2
Engine
Model D-237-347
Electric starter start
Rechargeable battery 6ST-90A, 2pcs (3CT-215, 2pcs.)
Operating power, kW (hp) 57.4 (78)
Specific fuel consumption, g / kWh (g / e.h.h.) no more than 235 + 3% (172.8 + 3%)
Crankshaft rotation frequency, rpm 2200
Working volume of cylinders, l 4.75
Transmission
The clutch is double-flow, dry, friction dry, permanently closed
Mechanical transmission, 9-speed with a reduction gear
Dry disc brakes
Semi-independent power take-off shaft (PTO)
PTO rotation speed, rev / s (rpm) 16.6k (1000) or 9 (540)
Hydraulic system
Separate-aggregate type with power and positional control system
Nominal pressure, MPa (kgf / cm2) 16.6 (160)
maximum 20-2 (200-20)
Hydrostatic steering with autonomous power supply
Tires
Front 9.00-20
Rear 15,5R38

Maintenance of the timing belt of the D-65 engines of the YuMZ tractor

Maintenance of the timing belt of the YuMZ tractor consists in periodic inspection of external parts, checking and installing the required thermal clearances between the rocker arms and valve stems, adjusting the decompression mechanism. The decompression mechanism is adjusted simultaneously
with adjustable thermal gaps.

Video (click to play).

The gaps between the valve stems and the rocker arm strikers are checked and adjusted after 500 hours of diesel operation, as well as after removing the cylinder head and when the valves knock.

The sequence of adjusting the valve clearances of the D-65 engine of the YuMZ tractor:

- remove the cylinder head cover;

- check the tightness of the nuts securing the rocker arm axle struts, tighten if necessary;

- turn on the decompression mechanism (if any);

- turn the engine crankshaft until both valves of the first cylinder close;

- unscrew the dowel pin from the flywheel housing and insert it into the same hole with the unthreaded part until it stops in the flywheel;

- pressing the adjusting pin, slowly continue turning the D-65 crankshaft of the YuMZ-6 tractor until the pin enters the hole on the flywheel. In this position of the flywheel, the piston of the first cylinder is at TDC during the compression stroke;

- turn off the decompression mechanism;

- measure with a feeler gauge the gaps between the inlet and outlet valve rods and the rocker arms of the first cylinder. If it is necessary to change the clearance, loosen the lock nut of the adjusting screw and, screwing or unscrewing it, set the required clearance. After tightening the lock nut,
check the size of the gap with a feeler gauge by turning the pusher rod around its axis (to make sure there are no bends);

- check the size of the gap in the decompression mechanism of the first cylinder, adjust if necessary. It should be borne in mind that if there is an excessive clearance in the decompression mechanism, the cylinder will not fully decompress, and if it is insufficient, the valves may hit the pistons due to the small distance between them when approaching;

- after the thermal clearances in the valves and the decompression mechanism of the first cylinder are adjusted, you need to remove the dowel pin from the flywheel housing and screw it there with the threaded part;

- turn the crankshaft of the D-65 diesel engine of the YuMZ tractor by half a turn, which, in accordance with the order of operation of the cylinders, will ensure the position of the piston of the third cylinder at TDC during the compression stroke, and adjust the clearances in the valve and decompression mechanisms of this cylinder in the sequence described above. The transition to the rest of the cylinders in accordance with the operating procedure is carried out after the next cranking of the crankshaft by half a turn (1800);

- start the engine and listen to the work. When knocking appears, stop and check the gaps again;

- during normal operation, turn off the engine and install the cylinder head cover.

Another way: the crankshaft is cranked until the valves in the first cylinder overlap (the inlet valve of the first cylinder opens, the exhaust valve closes) and the clearance in the fourth, sixth, seventh and eighth valves is adjusted (the valves are counted from the fan); the crankshaft is rotated one revolution, setting the overlap in the fourth cylinder, and the clearance in the first, second, third and fifth valves is adjusted.

Crank mechanism and adjustments of the D-65 engine of the YuMZ tractor

Disruption in the operation of the KShM is caused mainly by the wear of its parts. Premature wear can be caused by the following:

- incorrect running-in (overloading) of a new or repaired diesel engine of the YuMZ-6 tractor;

- long-term operation of the tractor diesel engine in an inappropriate thermal regime (below 70 or above 97 ° C);

- long-term operation of the diesel engine with a low crankshaft frequency;

- repeated start-up of a cold diesel engine at negative ambient temperatures without using a heater.

To assess the technical condition of the cylinder-piston group and the tightness of the valves, a compressor is used in the following sequence:

- start the diesel engine and warm it up to the liquid temperature in the cooling system 70. 80 ° С;

- stop the diesel engine, remove the injectors and install a compressor in turn instead of them (the shut-off screw must be closed);

- scrolling the crankshaft of the D-65 diesel engine with a starter (or starting engine);

- at compression strokes, the nominal pressure in the cylinder should be 2.5 ... 2.8 MPa, the minimum - 1.7 MPa;

- in the same sequence, the compression in the remaining cylinders is determined. The difference in readings between the cylinders (normal) - no more than - 0.05 MPa.

The technical condition of the parts of the cylinder-piston group is also determined by the combustion of crankcase oil. To do this, during a certain time of operation of the tractor, measure the amount of fuel and oil that is topped up (eliminated, before that, possible places of leakage).

If oil losses exceed 3% of fuel consumption, this indicates the ultimate wear of the cylinder-piston group of parts of the D-65 diesel engine of the YuMZ tractor.

An excessive amount of crankcase gases during diesel operation can also be caused by excessive wear of the parts of the cylinder-piston group of parts, coking or damage to the piston rings.

If the difference in the readings of the compression meter for individual cylinders is higher than the permissible values, 30.50 cm3 of engine oil is poured into the cylinders and the measurement is repeated.

Provided that the pressure has increased, it is possible to suspect the presence of leaks in the cylinder-piston group of parts, and if it has not changed, the tightness of the valves to the seats or the head to the cylinder block is broken.

To replace the gasket between the head and the cylinder block of the D-65 diesel engine of the YuMZ-6 tractor, perform the following work:

- loosen the fastening bolts of the clamps,

- remove the hoses and drainage pipe of the starting engine;

- unscrew the bolts and remove the gas outlet pipe of the starting engine;

- Disconnect the cylinder head and water inlet pipe, low pressure pipe and fuel filters, drain manifold, high pressure pipes and injectors;

- after unscrewing the bolts, remove the cylinder head cover;

- having unscrewed the fastening nuts, remove the fuel filter and the cylinder head of the D-65 engine of the YuMZ tractor;

- put the cylinder head and filter in place and secure with nuts;

- connect the low pressure pipes with filters, the low pressure pipes and the drain manifold with the nozzles;

- put the cylinder head cover in place and secure it with bolts;

- connect the water supply pipe to the cylinder head;

- put the flue gas pipe in place and fix it;

- put the water supply pipe of the starting engine in place;

- tighten the fastening bolts of the clamps on the connecting hoses.

To evenly press the head to the cylinder block, the nuts of the fastening studs must be tightened with a torque wrench in a certain sequence. The tightening torque should be 150.180 Nm.

Maintenance of the power supply system and fuel injection pump for D-65 engines of YuMZ-6 tractors

Mechanical impurities and water, which have a higher specific gravity than fuel, settle at the bottom of the tank. After every 500 hours of diesel operation, as well as in the presence of signs of water and fuel contamination in the tank, the sediment must be drained.

Simultaneously with the drainage of the sediment, the lid and filter of the tank filler neck are washed, the hole in the lid is cleaned. After 960.1000 hours of operation of the diesel engine, flush the fuel tank, clean and rinse the mesh of the intake union.

Low pressure fuel lines are made of 5.12 mm metal or PVC pipes. Their tightness is most often broken at the joints with the fitting due to crushing and wear of the ends.

Violation of the tightness of the lines located on the path of the fuel to the booster pump is detected through a fuel leak when the diesel engine of the YuMZ tractor is not working, in other places - through a leak during operation.

The defective end of the metal tube is cut off with a hacksaw, the butt is filed perpendicular to the axis and a pressure nut is put on. Before flaring, the tube is fired with a burner at a temperature of 600 ... 700 ° C. After firing, the tube is expanded and checked for leaks with diesel fuel under a pressure of 0.3 MPa for 1 min.

To connect the elbow to the PVC tube, cut off the damaged part, put a union nut on the tube and screw the elbow into the tube hole, holding the nut with a wrench. To facilitate assembly, it is recommended that the end of the tube be heated in hot water.

Maintenance of fuel filters consists in draining fuel sludge, flushing filter elements without disassembling filters, flushing with complete disassembly of the coarse filter, flushing the housings of fine fuel filters and replacing paper filter elements.

The technical condition of the filter elements largely depends on the filterability of the fuel. Fuel filterability is influenced by its chemical composition. Some compounds, especially naphthenic acids, reduce filterability.

At the same time, fine fuel filters become clogged, precipitates are formed in coarse filters. Filtration is especially impaired in the presence of water: naphthenic acids form with it soapy, loose sediments.

Maintenance of the lubrication system of the D-65 engine of the YuMZ-6 tractor

To ensure the normal operation of the lubrication system of the D-65 diesel engine of the YuMZ tractor, you need to: fill in the oil pan only with the recommended oils corresponding to the season of operation; fill the system up to the upper mark on the dipstick; maintain the pressure in the system within the specified limits.

The oil level in the sump is checked no earlier than 10 minutes after stopping the diesel engine. Insufficient oil pressure may be due to poor oil quality, high oil temperature, malfunction of the drain valve or pump, poor condition of the crankshaft bearings, etc.

When operating a diesel engine with a rated speed and a coolant temperature of 70–95 ° C, the oil pressure should be 0.2… 0.3 MPa. If it is below 0.1 MPa under such conditions, you need to stop the diesel engine and find and eliminate the cause of the pressure drop. If necessary, the pressure can be adjusted by tightening the spring of the centrifugal filter drain valve.

The technical condition of the centrifuge is determined by ear: after stopping the D-65 diesel engine of the YuMZ tractor, its rotor must rotate for at least 30 seconds, creating a uniform characteristic noise.

The absence of such noise or its short duration indicates that the centrifuge is dirty, malfunctioning or low pressure of the oil entering the rotor. In this case, the centrifuge must be disassembled.

The operation to clean the centrifuge rotor is performed after 250 hours of operation in the following sequence:

- unscrew the cap nut and remove the filter cap;

- a screwdriver is inserted between the body and the bottom of the rotor (they stop the rotor from turning) and the glass and the rotor body are loosened with a wrench;

- check and, if necessary, clean and wash the rotor protective screens;

- using a wooden scraper, remove the layer of deposits from the inner walls of the glass, if necessary, clean the nozzle holes in the upper part of the rotor column. Copper or brass wire with a diameter of 1.5. 1.8 mm clean the nozzle centrifuge nozzles;

- assemble the rotor in reverse order.

To maintain the balance of the rotor, the marks applied to the base and the cover must be aligned. The cover nut is tightened with a minimum torque that ensures tightness. After fastening, the rotor is screwed on by hand, checking the ease of rotation.

In the process of using the YuMZ-6 tractor, the condition of the engine oil deteriorates. In accordance with the standards, the engine oil change is foreseen after 250 hours of operation, but it may be required earlier.

For an approximate assessment of engine oil contamination, you can use a drop sample: immediately after stopping the diesel engine, using a dipstick, take a drop of oil from the oil pan and lower it onto a sheet of filter paper placed horizontally; after 2..4 hours (depending on temperature) the drop dries up, characteristic areas will be visible on the spot (Fig. 2.78): central core 1, ring 2, diffusion zone 3.

When analyzing a spot, you need to pay attention to the fact that if the core is a solid black spot, an oil change is needed.

The breather is serviced after 1000 hours of operation: the housing is removed, the oil is a reflector, a glass with a tube. Everything is cleaned, washed, blown with compressed air.

The final drive is a pair of bevel gears with circular teeth. The drive gear 1 (Fig. 1) is made as one piece with the secondary shaft of the gearbox, and the driven gear 7 is in the form of a crown, which is fixed with six bolts and two special bolts 6 on the hub 30. Read more →

In order to reduce the effort on the steering wheel when turning the tractor, there is a hydraulic booster. The steering gear ratio with the hydraulic booster is less than without the hydraulic booster, which provides a higher maneuverability of the tractor. Power steering Read more →

Cooling system ……………………………………………………… ..28L

Engine lubrication system ……………………………………………… .16l

Fuel pump housing …………………………………………… ..0,17l

Fuel pump regulator housing …………………………… ..0,35L Read more →

Differential bearing adjustment.

The axial clearance in the differential bearings should be checked after 3000 hours of operation during the next maintenance. The check is carried out by moving the differential with a mounting paddle or by hand. Tighten the body flange and axle cover bolts before checking. If the movement of the differential can be felt by hand, then the bearings must be adjusted. For example, axial Read more →

Belarus tractors MTZ-80, MTZ-82, MTZ-82.1, MTZ-1221, 1523, MTZ-892, YuMZ, T-40. Agricultural machinery: plows, cultivators, walk-behind tractors, mowers, seeders

SPARE PARTS FOR TRACTORS

ADJUSTMENT OF MTZ TRACTORS ___________________

DIESEL ENGINE PARTS ___________________

SPARE PARTS CATALOGS MTZ ___________________

TECHNICAL CHARACTERISTICS OF TRACTORS ___________________

SPECIAL EQUIPMENT BASED ON MTZ AND ATTACHED EQUIPMENT ___________________

AGRICULTURAL MACHINERY AND EQUIPMENT ___________________

Clutch device of the YuMZ tractor

The clutch of the YuMZ tractor is two-flow (main and PTO). The two driven discs with friction lining differ in the dimensions of the hubs.

The YuMZ clutch has a driven disc 10 (Fig. 1), which is put on the splines of the shaft 6, passed through the tubular shaft 18 and transmitting the rotation to the gearbox, and the driven disc 12 of the PTO clutch is on the splines of the tubular shaft 18.

Rice. 1. Clutch YuMZ (driven disc PTO drive)

14 - support disk; 15 tubular shaft; 19 - driven gear wheel of PTO drive;

Fig. 2.Clutch device of the YuMZ tractor (control mechanism)

1 - clutch housing; 2-flywheel; 3 - thrust; 4, 5 - springs; 6 - shaft: 7 - bearing; 8 - needle bearing; 9 - thrust bushing of the layering; 10 - driven disk; 11 and 13 - front and rear pressure discs; 12 release lever; 16 - layering body; 17 - layering bracket; 18.20 - layering fork; 21 - fork roller; 22 - lever; 23 - the leading finger of the pressure discs; 24 - stop bolt; 25 - spring; 26 - emphasis; 27 - blocking roller lever; 28 - blocking roller; 29 and 32 - thrust; 30 - pedal; 31 - servo lever; 33 - latch; 34 - latch pedal

In the clutch of the YuMZ tractor, the pressure discs are tightened by six springs 4, put on the rods 3.

When the main clutch of the YuMZ is turned off, the pressure discs 11 and 13, while moving, release only the driven disc 10, as a result of which the transmission of rotation to the shaft 6 stops and the tractor stops, and the disc 12, remaining clamped by the springs 4, continues to transmit rotation to the PTO.

The joint movement of the discs 11, 12 and 13 continues until the disc 11 with its stops 26 reaches the three bolts 24 screwed into the clutch housing.

If after that you continue to press the pedal, then only one disc 13 will move back, overcoming the resistance of not only the springs 5, but also the springs 4. Thus, the YuMZ clutch disc (12) will be released and the transmission of rotation to the PTO will stop.

The position of the pedal corresponding to the disengagement of the main clutch without disengaging the PTO is fixed.

The pedal can move until the blocking roller 28 (Fig. 2), pivoted by the rod 29 and the lever 27, rests with its flat against the latch on the shaft 32. This position corresponds to the release of the driven disc (10).

If it is necessary to disengage the PTO clutch, then by pressing the pedal 34, the latch is pulled back and the blocking roller 28 is released, which allows the pedal 30 to be pressed all the way. In the upper position, the pedal 30 is held by the servo spring.

The clutch on the latest models of YuMZ tractors, in contrast to the one discussed above, has an additional two-speed PTO switch and a mechanical control drive with a hydraulic booster.

Clutch adjustment YuMZ

Adjusting the clutch of the YuMZ tractor includes the following steps:

Adjusting the pedal free play (the gap between the thrust bushing of the cutter and the release levers)

Adjustment of the pedal travel until it stops in the latch, which ensures complete disengagement of the main clutch;

Adjustment of the gap between the stop bolts and the front pressure plate, which ensures the disengagement of the main PTO drive without disengaging the clutch.

Clutch adjustment YuMZ is carried out in the following sequence:

The free travel of the clutch pedal of the YuMZ tractor is set within 30 + 5 mm by changing the length of the thrust. To increase the free play, the traction should be lengthened, and to decrease it should be shortened.

Check the pedal travel until it stops in the latch, which should be 145 ± 5 mm. If necessary, the pedal stroke is adjusted by the blocking roller drive rod. To increase the pedal travel, the thrust is shortened, and to decrease it, it is lengthened.

The UMZ servo amplifier mechanism is adjusted so as to ensure the minimum effort on the pedals when disengaging the clutch and a clear return of the pedal to its original position.

Adjustment is made by moving the servo amplifier bracket along the oval holes. The springs of the servo amplifier are pressed with a stop screw, for which it is unscrewed by 3-8 mm.

Remove the lower hatch cover in the YuMZ clutch housing and tighten the bolts 24 until they stop (see Fig. 1), and then turn each of them 7/6 of a turn (seven clicks of the locking device).

With strong wear of the driven discs, the clutch is adjusted by changing the position of the release levers while simultaneously changing the length of the main link.

This adjustment of the YuMZ clutch is performed in the following sequence:

Remove the lower clutch hatch cover.

Adjust the release levers with the nuts so as to provide a size of 73.5 mm between the end face of the PTO driven disk hub and the release lever cams;

Change the length of the main thrust and set a gap of 3-4 mm between the thrust sleeve of the cut-off and the release levers. The difference between the gaps for the three arms should not exceed 0.3 mm. After the final establishment of the gap, the nuts of the release levers are pinned;

Bolts 24 are screwed in until they stop, and then each of them is released 7/6 of a turn. When a new or repaired (with replacement of discs) clutch of the YuMZ tractor is operating, an intensive running-in of the discs occurs and the initial adjustment is violated.

For the period of running in the YuMZ clutch (about 30 hours of tractor operation), the gap between the bushing sleeve and the release levers is allowed 3 + 1 mm, and the difference in the clearances for the three release levers should not exceed 1.3 mm.

Tractor clutch YuMZ-6 KL, YuMZ-80/82

Tractor YuMZ-6 KL, YuMZ-6 KM are universal agricultural tractors with 4K2 wheel arrangement.

The clutch housing of the YuMZ-6 KL, YuMZ-6 KM tractors contains the main clutch and the power take-off shaft clutch (with a separate drive).

This clutch differs from each other only in the design and arrangement of the control mechanism.

In the clutch of the YuMZ-6 tractor, the gap between the safety ring 6 (see Fig. 3) of the release levers 4 and the thrust sleeve 7 of the release bearing, as well as the gap between the thrust bolts 8 and the stops 9 on the pressure plate 3 of the main clutch, are adjusted.

Rice. 3. Coupling of tractors YuMZ-6 KL, YuMZ-6 KM and YuMZ-80, YuMZ-82

1 - oiler; 2 - driven disk; 3 - pressure plate; 4 - release lever; 5 - an adjusting nut; 6-safety ring; 7-thrust bushing; 8 - stop bolt; 9 - emphasis; 10 - roller of the PTO shifting mechanism; 11 - plug; 12, 13 - driven gears of I and II stages of PTO; 14 - leash of the PTO shift mechanism

Clutch adjustment of the YuMZ-6 KL, YuMZ-6 KM tractor

Remove the bottom hatch cover in the clutch housing.

Tighten the stop bolts 8 until they come into contact with the stops 9, and then unscrew each of them by seven clicks of the locking device, which corresponds to a gap of 1.75 mm between the stop bolts and stops 9.

Rice. 4. Clutch control of tractors YuMZ-6, YuMZ-80/82

a - tractor YuMZ-6 KL, YuMZ-6 KM

1 - nut; 2, 6 - thrust; 3 - blocking roller; 4 - emphasis; 5, 7 - levers; 8 - bolt; 9 - bracket; 10 - screw; 11 - hydraulic booster; 12, 13 - delivery and drain oil pipelines; 14 - finger; 15 - retainer; 16 - pedal; 17 - handle; A - pedal stop;

b - tractor YuMZ-80, YuMZ-82

1 - pedal; 2, 16-thrust; 3 -catch; 4 - handle; 5, 12 - springs; 6 - lever; 7 - nut; 8 - rocking chair; 9 - bracket; 10 - an adjusting screw; 11 - bracket; 13 - hydraulic booster; 14 - layering lever; 15, 18 - fingers; 17 - traction plug; 19 - lever; A - thrust; B - oil drain into the tank; B - groove in the lever; D - oil supply from the pump, P - groove in the holder

Disconnect the rod 6 (see Fig. 4, a) of the drive of the YuMZ-6 clutch control mechanism from the lever 7 of the release.

Turn the lever 7 up to the stop of the release bearing against the safety ring of the release levers, and then release it 4.5 mm, which corresponds to a gap of 3-4 mm between the safety ring and the thrust sleeve of the release bearing.

Adjust, without changing the position of the lever 7, the length of the rod 6 until the holes in the rod coincide with the hole in the lever and connect them.

After significant wear of the clutch discs of the YuMZ-6 tractor, restoring the gap between the safety ring of the release levers and the thrust sleeve of the release bearing by changing the length of the thrust 6 may be impossible. In this case, you need to change the position of the release levers, and then shorten the link.

Adjustment of clutch release levers YuMZ-6 KL, YuMZ-6 KM

Remove the cover of the lower hatch in the YuMZ-6 clutch housing, unpin the nuts 5 (see Fig. 1) of the release levers rods.

Adjust the position of the release levers 4 by turning the nuts 5 so that the safety ring is at a distance of 83 ± 0.5 mm from the plane of the hub flange of the PTO driven disk 2.

After adjustment, the safety ring must be in a plane perpendicular to the axis of rotation, that is, in a plane parallel to the thrust sleeve 7 of the release bearing. The non-parallelism should not exceed 0.3 mm. Before the final check of parallelism, nuts 5 must be pinned.

After replacing discs or other repairs of the YuMZ-6 clutch, the position of release levers 4 must also be adjusted with nuts 5 so that the distance between the plane of the hub flange of the PTO driven disc 2 and the plane of the safety ring 6 is 83 ± 0.05 mm.

Adjustment of the clutch control mechanism YuMZ-6 KL, YuMZ-6 KM

In case of repair or replacement of parts of the YuMZ-6 clutch control mechanism, it must be adjusted in the following sequence:

Disconnect the rod 6 (see Fig. 4, a) from the lever 7 and release the pedal by unscrewing the nuts 1.

Make sure that the bracket 9 through the bolt 8 abuts against the wall of the clutch housing. Adjust the bolt position if necessary.

Bring the lever 5 to the stop 4 by turning the screw 10.

Adjust the gap between the thrust sleeve of the release bearing and the safety ring of the release levers of the YuMZ-6 clutch and connect the rod 6 with the lever 7.

Adjust the gear locking mechanism by changing the length of the rod 2.

Start the engine and check the operation of the drive.

Please note that after starting the engine, lever 5 must remain on the stop 4. If, after starting the engine, the lever moves away from the stop, you need to loosen the nuts 1. The pedal must remain pressed against the stop A.

Adjustment of the hydraulic booster safety valve of the clutch control mechanism YuMZ-6 KL, YuMZ-6 KM

In the event of disassembly-assembly or signs of a malfunction of the safety valve, it is necessary to check the pressure and adjust the valve in the following sequence:

Disconnect the oil drain line 13 from the hydraulic booster (with the engine stopped) and install a pressure gauge in its place.

Plug the disconnected oil line, as oil will leak from the valve when checking the valve.

Start the engine, set the maximum crankshaft speed and read the pressure gauge.

If necessary, adjust the valve to a pressure of 3 ± 0.5 MPa, while the oil temperature should be 50 ± 5 ° C.

Adjustment of the YuMZ clutch locking mechanism

If it is difficult to shift gears, it is necessary to adjust the YUMZ locking mechanism in the following sequence:

Disconnect link 2 from blocking roller 3.

Turn the blocking roller to the position where the gears are freely shifted, and put one of the gears on the floor in the engaged position.

Press the pedal 16 until it stops in the retainer 15. If it is difficult to press the pedal, release it by unscrewing the nuts 1.

Turn the blocking roller 3 clockwise until its edges come into contact (to the touch) with the catch in the gearbox.

Adjust the length of the rod 2, keeping the indicated position of the pedal and the blocking roller, and install it in place.

Check the YUMZ traction adjustment by shifting gears with the clutch pedal depressed. If gear shifting is difficult, shorten the traction by 0.5-1 turn of the fork.

Tighten nuts 1 (if they have been loosened) and check that they are tightened correctly. The nuts are tightened correctly if pedal 16 is pressed against stop A and after starting the engine, lever 5 remains on stop 4.

Clutch adjustment YuMZ-80, YuMZ-82

Set the gap between the thrust sleeve of the release bearing and the safety ring of the release levers equal to 4 + 0.5 mm, for which it is necessary:

Unpin and remove pin 18 (Figure 2, b);

Using the screw 10, set the hydraulic booster 13 with the lever 14 to the upper extreme position;

Unscrew the screw 10 by 3 turns and lock, which corresponds to a gap of 4 + 0.5 mm between the safety ring of the release levers and the thrust sleeve of the release bearing, and, therefore, the free travel of the clutch pedal YuMZ-80, YuMZ-82, equal to 30 + 10 mm , the hydraulic booster piston should be in the lower extreme position;

Adjust the length of the rod 16 with the fork 17 until the holes in the rod and lever 19 are aligned.

Insert and cotter pin 18.When installing thrust 16, pedal 1 should rest against stop A, and the piston and power steering valve should be in the lower extreme positions.

Adjustment of the YUMZ gearshift locking mechanism drive:

Using the bracket 9 through the rocker 8, align the groove P in the holder and the groove B in the lever 6;

Make sure that pedal 1 rests against stop A.

Start the engine and check the operation of the drive. The adjusted gear blocking mechanism must ensure the unlocking of the rollers of the synchronized gearbox when the pedal is pressed against the stop 3.

§ 13. The device of the gas distribution mechanism.

at certain times, it opens and closes the intake valves, due to which fresh air enters the cylinders in a timely manner and the exhaust gases are removed.

The D-50 and D-65 engines use a valve timing mechanism with an overhead valve arrangement (20).

It includes intake and exhaust valves with springs, rocker arms with rollers and struts, rods, push rods, camshaft and timing gears.

The gas distribution mechanism operates as follows. The crankshaft of a running engine with the help of gears rotates the camshaft 14. The cam of the camshaft, running on the pusher 13, raises it together with the rod 12. The rod lifts one end of the rocker arm 7 with an adjusting screw, the other end of which moves down and presses on the valve 3, lowering it and compressing the valve springs b.

When the camshaft cam comes off the tappet, the rod and tappet are lowered and the valve spring tightly closes the seat.

The valves are used to open and close the inlet and outlet openings. They consist of a head and a rod. For a better fit to the socket, each valve is lapped to a 1.5 mm wide chamfer made at an angle of 45 and carefully ground. To make the valves work longer, they are made of special steels: inlet - from chromium, and outlet - from heat-resistant (silchromic). For better filling of the cylinder with air, the diameters of the seats and heads of the intake valves are larger than the diameters of the seats and heads of the exhaust valves.

20. Diagram of the gas distribution mechanism;

1 - piston, 2 - valve seat, 3 - valve, 4 - cylinder head, 5 - valve guide sleeve, 6 - spring, 7 - rocker arm, 8 - decompressor screw, V - rocker arm adjusting screw, 10 - lock nut, 11 - rack rocker shaft, 12 - rod, 13 - pusher, 14 - camshaft, 75 - camshaft gear, 16 - crankshaft gear

In the upper part of the valve stem, there is a groove for installing conical crackers, with the help of which the valve is firmly held in the spring plate. To close the valve and fit it tightly in the socket, two springs are installed (one into the other).

The rocker arm is a two-armed lever made of steel. In its middle part there is a thickening with a hole, into which the bushing is pressed. In one arm, the rocker arm has a hardened firing pin, with which it presses on the valve, and in the other - a threaded hole, into which the adjusting screw 9 is screwed. Using the adjusting screw, set the required clearance between the valve and the rocker arm.

The rocker arm swings freely on the axis, which is installed on the posts 11, screwed to the head of the block. Distance springs 3 (21) and retaining rings hold the rocker arm against axial displacement.

The rod is made of steel bar with hardened ends. The lower end of the rod is spherical. The upper end is cup-shaped. It contains the lower part of the adjusting screw.

The pusher for the D-65 engine is made of steel in the form of a cup, while for the D-50 engine it has a mushroom shape.

1 - decompressor handle, 2 - decompressor shaft, 3 - spring, 4 - rod, 5 - pusher, 6 - intake cams, 7 - camshaft, 8 - camshaft journal, Y - gear, 10 - ring, 11 - thrust flange, 12 - valve

The camshaft 7 serves to timely open and close the valves in a specific sequence. Eight cams and three bearing journals are made together with the shaft. The two outer and two middle cams of the shaft are for the exhaust valves, and the rest are for the intake valves. The cam profile of the exhaust valves is duller, so they open for a longer time than the intake ones. The shaft journals rotate in bushings pressed into the block. The journals are lubricated through a channel drilled inside the shaft. The oil enters the channel from the middle main bearing of the crankshaft through the middle journal of the camshaft.

From axial movement, the camshaft is held by a thrust flange 11. Between the flange and the gear is a bronze ring 10, which acts as a thrust bearing.

Gear 9 is attached to the front end of the camshaft using a key and a bolt with a washer.

Oil is led to the rubbing surfaces of the transmission parts through vertical drilling in the block and the block head through the tube 3 (22) into the hollow axis of the rocker arms.

Distribution gears - steel helical gears are located in the front of the engine in a special crankcase. They include the crankshaft gear 12 and the camshaft gear 9.

In order for each valve to open once in two revolutions of the crankshaft of a four-volume engine, the camshaft rotational speed must be half the rotational speed.

the crankshaft and therefore the camshaft gear is twice the size of the crankshaft gear.

To transmit rotation from the crankshaft to the camshaft, there is an intermediate gear 8 located between the gears of these shafts. The idler gear on the other side rotates

Details of the gas distribution mechanism of the D-50 engine:

1 - camshaft, 2 - rod chamber cover, 3 - oil supply pipe to the valve mechanism, 4 - exhaust valve, 5 - inlet valve, 6 - oil filler neck, 7 - fuel pump drive gear, 8 - intermediate gear, 9 - gear camshaft, 10 - thrust ring, 11 - moto-hour counter, 12 - crankshaft gear, 13 - front engine support, 14 - camshaft housing, 15 - hydraulic pump drive gear, 16 - pusher.

Fig. 23. Scheme of installation of distribution gears by labels:

a - D-50 engine, 6 - D-65 engine; 1 - camshaft gear, 2 - intermediate gear, 3 - fuel pump drive gear, 4 - crankshaft gear, 5 - hydraulic pump drive gear.

gear 7 of the fuel pump drive. In order for the action of the valves and the fuel supply to correspond to a certain position of the piston in the cylinder, the teeth of the indicated esters are connected by marks during assembly. The gear 15 of the drive of the hydraulic pump receives rotation from the gear of the camshaft, and the gear of the drive of the oil pump rotates from the gear of the crankshaft. These gears are installed on the engine without marks.

Video (click to play).

The installation of gears according to the marks is shown in Fig. 23.

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