General information
The flywheel is cast from cast iron and ensures uniform operation of the engine. In addition, the flywheel serves as a clutch support. A toothed crown is installed along the perimeter of the flywheel's generating surface, into engagement with which the starter drive pinion is introduced when the engine is started.
The toothed ring is made of steel and hardened by high-frequency current. The ring is pressed onto the flywheel body after preliminary heating to a temperature of 180÷200°C.
The friction surface of the flywheel, mating with the clutch disc, is subjected to very careful mechanical treatment.
The flywheel is attached to the crankshaft flange using four M10x1 bolts, which are secured with a special washer, common to all four bolts.
All flywheels are statically balanced (the permissible imbalance is no more than 0.1 Nm). After fitting onto the crankshaft, the flywheel assembly is dynamically balanced.
During vehicle operation, the flywheel rear surface interacting with the clutch disc and its toothed crown are subject to wear. Repair of the flywheel rear surface consists of regrinding it on a special grinding machine, observing the necessary tolerances. As for the crown, if signs of significant wear of the teeth or their damage are detected, it is subject to replacement.
The worn crown is removed from the flywheel using a press. Alternatively, one or more holes with a diameter of 12÷13 mm are drilled in the crown base so that the crown cracks. Try not to damage the flywheel itself.
Before installation, the new crown should be heated in an electric furnace to a temperature of 180÷200°C. The hot crown is placed on a flat surface, then the flywheel is pressed into it, which is best cooled beforehand.
When removing the flywheel from the crankshaft, remember that it has been subjected to dynamic balancing, and therefore must be installed during assembly strictly in the same position - apply the mounting marks.
Removal
1. Remove the manual transmission (see Chapter Transmission) and clutch assembly (see Chapter Clutch).
2. Using a locking device made from a thick metal plate, wedge the flywheel ring gear, blocking the latter from turning while loosening its mounting bolts. Alternatively, the flywheel can be blocked using a metal plate bolted between it and the cylinder block.
3. Unscrew the flywheel mounting bolts. They must be replaced during assembly.
4. Mark the position of the flywheel in relation to the end of the crankshaft journal to avoid imbalance during assembly.
5. Carefully remove the heavy flywheel.
Examination
1. Check the condition of the flywheel surface mating with the clutch disc. If deep scratches, cracks, scoring and other mechanical damage are detected, the flywheel must be replaced or given a turning (consult with car service specialists).
2. Carefully inspect the flywheel ring gear. If the teeth are worn or missing, the ring gear should be replaced at a car service workshop.
3. Using a tap, run the threaded holes in the end of the crankshaft journal and remove any remaining sealant and corrosion products from them.
Installation
1. After thoroughly cleaning the mating surfaces, install the flywheel on the crankshaft journal in accordance with the fit marks made during dismantling.
Note: The new flywheel can be installed in any position.
2. If the new mounting bolts are not coated with a locking compound at the factory, lightly lubricate their threads with a suitable sealant. Screw the bolts in and tighten them only by hand for now.
3. Using one of the methods suggested above, lock the flywheel from turning, then tighten the mounting bolts to the required force.
4. Install the clutch and gearbox assemblies in place (see Chapters Clutch and Transmission).