The crankshaft is cast from ductile iron, five-bearing, has eight counterweights for better unloading of the supports

The wear resistance of the main, connecting rod journals and the surface of the rear flange under the cuff is ensured by hardening with high frequency currents.

The fillets of the main and connecting rod journals of the shaft are rolled with rollers to harden them.

The shaft is dynamically balanced.

Removal and disassembly of the crankshaft can be found in the article - Removal and disassembly of the engine crankshaft.

Subassembly of the connecting rod and piston group can be found in the article - Subassembly of the connecting rod and piston group.

In the main (except for the middle) and connecting rod journals, through holes are drilled, which are connected by oblique drillings passing through the necks and cheeks of the shaft, these channels serve to supply oil to the connecting rod bearings.

At the exit point of the drillings in the cheeks there are special dirt trapping cavities closed with screw plugs.

During the rotation of the crankshaft, the dirt in the oil is separated due to the action of the centrifugal force of inertia and accumulates in these cavities.

There is an additional, in addition to the filter, oil cleaning.

When repairing the engine, the plugs must be turned out and cleaned of the dirt trapping cavities and oil channels of the crankshaft from dirt and deposits.

Threaded plugs are installed on Stopor-9 anaerobic sealant to prevent their self-loosening.

Middle (thrust) crankshaft bearing: 1 - cylinder block 2 - main bearing shells; 3 thrust washers: 4 - main bearing cap: 5 - crankshaft

The axial movement of the shaft is limited by two washers 3 (Figure 1) located on both sides of the middle (third) main bearing.

Each of the thrust washers consists of two half washers: upper and lower.

The direction of rotation of the crankshaft is right (when viewed from the side of the damper pulley).

At the front end of the crankshaft are installed: drive sprocket 7 of the camshaft drive, bushing 6 and pulley - damper 3 with a toothed synchronization disk, which are fixed with a coupling bolt 1

To prevent self-loosening of the coupling bolt, a toothed heat-strengthened washer 15 was used.

The outer surface of the steel sleeve 6 is hardened by high frequency currents to increase wear resistance.

Front end of the crankshaft with single-ribbed pulley: 1 - pinch bolt; 2 - parallel key; 3 - pulley-damper with a toothed synchronization disk; 4 - cuff; 5 - chain cover; 6 - bushing; 7 - asterisk; 8 - segment key; 9 - cylinder block; 10 - main bearing shells, 11 - crankshaft; 12 - main bearing cap; 13 - oil sump; 14 - rubber sealing ring; 15 - lock washer

The front end of the crankshaft is sealed with a reinforced single-lip rubber cuff with a spring and anther, as well as a rubber ring 14 (Figure 2) installed between the spacer sleeve and the sprocket.

The crankshaft damper pulley has a special elastic rubber element that serves to dampen the torsional vibrations of the crankshaft, thereby reducing noise and facilitating the operation of the camshaft chain drive.

Damper pulley statically balanced.

The ring gear of the damper pulley is used to supply pulses to the synchronization sensor, with the help of which the microprocessor unit of the control system determines the crankshaft speed and the position of the crankshaft relative to TDC.

A risk is applied on the damper disk, by coincidence with which the protrusion on the chain cover determines whether the piston of the first cylinder is at TDC.

Rear end of crankshaft: 1 - crankshaft, 2 - main bearing shells, 3 - cylinder block, 4 - stuffing box, 5 - rear oil seal, 6 - flywheel, 7 - flywheel locating pin, 8 - spacer, 9 - flywheel bolt washer, 10 - transmission input shaft toe bearing, 11 - flywheel bolt, 12 - oil pan, 13 - main bearing cap

On the cylindrical protrusion of the rear end of the crankshaft (Figure 3) and pin 7, pressed into the rear flange of the crankshaft, a flywheel 6 is installed, attached to the flange with six self-stops bolts 11 through a heat-strengthened washer 9.

Heat-strengthened washer is used to increase the reliability of the connection.

The spacer sleeve 8 and the bearing 10 of the toe of the gearbox input shaft are installed in the flywheel seat.

The rear end of the crankshaft is sealed with a reinforced single-lip rubber cuff 5 with a spring and anther installed in the stuffing box holder 4.

The centering of the rear seal 5 relative to the crankshaft is achieved thanks to the protrusions of the stuffing box.

Flywheel — cast from gray cast iron, has a press-fitted steel ring gear hardened by high-frequency currents.

The flywheel is centered relative to the crankshaft by landing it on a cylindrical protrusion of the rear flange of the crankshaft.

The flywheel is statically balanced separately from the crankshaft.

The bearing shells of the crankshaft and connecting rods are steel-aluminum.

Upper main bearing shells with grooves and oil hole, lower ones without grooves.

The upper and lower shells of the connecting rod bearings are the same, with a hole for supplying oil to the oil channel of the connecting rod.

The thrust bearing lower half washers have a lug that fits into the groove in the middle main bearing cap.

Special grooves are made on the anti-friction layer of half washers.

When installing, the half washers must face the grooved surface towards the crankshaft.

The controlled parameters of the crankshaft when checking the technical condition are given in the table.

In the presence of cracks of any nature, the crankshaft must be rejected.

Removal of wear and carbon deposits from the cavities of the connecting rod journals of the crankshaft: 1 - oil channel plug, 2 - crankshaft

To remove deposits from the cavities of the connecting rod journals and oil channels, it is necessary to unscrew four plugs from the connecting rod journals, rinse with a solution of caustic soda (NaOH) heated to plus 80 ° C, and thoroughly clean the cavities and channels with a metal brush.

Rinse the cavities with kerosene and dry with compressed air, then screw the plugs back in place with a torque of 37-51 Nm (3.8-5.2 kgcm), having previously applied Stop-9 anaerobic sealant to their threaded surface.

In the process of operation, the main and connecting rod journals of the crankshaft wear out, lose their geometric shape, which reduces the performance of the crank mechanism, causes increased wear of the cylinders and piston rings, while the piston pin may push the circlips out of the grooves in the piston and the piston piston pin.

The main and connecting rod journals of the crankshaft take the shape of a cone and an oval as a result of wear.

If the main and connecting rod journals are worn out more than the maximum allowable dimensions and if the taper and ovality of the journals are more than 0.04 mm, then the shaft journals must be ground to one of the repair sizes.

All necks of the same name are ground to the same repair size.

The sharp edges of the chamfers of the oil channels are blunted with a conical abrasive tool, and then the necks and chamfers are polished.

The radii of the fillets of the main and connecting rod journals are 2 mm.

If the surface of the rear flange or the surface of the hub of the pulley - damper under the working edge of the cuff is worn, move the cuff to contact its working edge with a non-worn surface and prevent oil leaks, to do this, install a spacer ring between the cuff and the stuffing box or chain cover.

If the thread in the holes is damaged up to two threads, it is restored by running to the size of the working drawing.

If two or more threads are broken, then repairs are made:

  • - thread in the holes for the flywheel mounting bolts - by installing threaded spiral inserts,
  • - thread in the hole for the tie bolt - by cutting a repair thread;
  • - threads in plug holes - by cutting repair threads

Controlled parameters during crankshaft repair

Parameters to be monitored during crankshaft repair


Design and repair of the ZMZ-405 crankshaft

The crankshaft is balanced using the dynamic balancing method.

Permissible imbalance - 18 gsm, in planes passing through the extreme main journals.

Remove imbalance by drilling holes Ø 14 mm, to a depth of not more than 25 mm in the radial direction from counterweights.

Intersection of holes and exit on the surface of the ends of counterweights is not allowed.

Damper pulley balancing: 1 - damper pulley; 2 - mandrel, 3 - device for static balancing

The crankshaft damper pulley is balanced using the static balancing method.

Permissible imbalance is 15 gsm.

The imbalance is eliminated by drilling holes Ø 10 mm, to a depth of not more than 12 mm, taking into account the cone of the drill in the damper disk in the radial direction at a distance of 10.5 mm from the rear plane.

The distance between the axes of the holes is at least 18 mm.

Flywheel balancing: 1 flywheel, 2 mandrel, 3 static balance tool

The flywheel is balanced by a static method.

Permissible imbalance 15 gsm.

The imbalance is eliminated by drilling holes Ø 14 mm, to a depth of not more than 12 mm, taking into account the cone of the drill on the side opposite to the clutch mounting at a radius of 115 mm.

Drill no more than 10 holes.

The distance between the axes is at least 18 mm.