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 strengthen them. The shaft is dynamically balanced.
Removal and disassembly of the crankshaft can be found in the article - Crankshaft ZMZ-4062 auto GAZ-2705
The subassembly of the connecting rod and piston group can be found in the article - How to assemble the connecting rod and piston group of the ZMZ-40524 engine
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.
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: a drive sprocket 7 of the camshaft drive, a bushing 6 and a pulley - damper 3 with a timing gear 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.
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 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.
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-locking bolts 11 through a heat-strengthened washer 9.
The heat-strengthened washer is used to increase the reliability of the connection. A spacer sleeve 8 and a bearing 10 of the toe of the gearbox input shaft are installed in the flywheel socket.
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.
The flywheel is cast from gray cast iron, has a pressed 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 subjected to a static ball anchoring separately from the crankshaft.
The bearing shells of the crankshaft and connecting rods are steel-aluminum. Upper main bearing shells with grooves and oil supply 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 middle main bearing cap groove. 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.
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 Stopor-9 anaerobic sealant to their threaded surface .
During 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.
When 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 torn off, then repairs are made:
- thread in the holes for the flywheel mounting bolts - by installing threaded spiral inserts,
- thread in the hole for the coupling bolt - by cutting a repair thread;
- threads in plug holes - by cutting repair threads.
Controlled parameters during crankshaft repair
The crankshaft is balanced using the dynamic balancing method.
Permissible imbalance - 18 gsm, in planes passing through the extreme main journals.
The imbalance is eliminated 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.
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.
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 from the opposite side opposite to the clutch mount on a radius of 115 mm.
Drill no more than 10 holes. The distance between the axles is at least 18 mm.