The surfaces of the flywheel mating with the crankshaft and with the clutch disc must be free from scratches, burrs and be perfectly flat.
If on the work surface 3 (pic. 2-38) there are scratches on the flywheel under the clutch disc, grind this surface, removing a layer of metal no more than 1 mm thick. Then machine surface 2, maintaining a dimension of 0.5±0.1 mm and ensuring the parallelism of surfaces 2 and 3 relative to surface 1. The permissible non-parallelism, measured at the extreme points of surfaces 2 and 3, should not exceed 0.1 mm.
Pic. 2-38. Flywheel: 1 - mounting surface to the crankshaft flange; 2 - clutch mounting surface; 3 - bearing surface of the clutch driven disk: B - place for checking the runout of surface 2; C - place for checking the runout of the surface 3
Install the flywheel on the arbor, centering it on the mounting hole with an emphasis on surface I, (pic. 2-38) check the runout of planes 3 and 2. At points B and C, the indicator should not show runouts exceeding 0.1 mm.
Checking the axial clearance of the crankshaft
The axial movement of the crankshaft is limited by two retaining half rings mounted on both sides of the rear main bearing. A steel-aluminum semi-ring is installed in the front side of the bearing, and a metal-ceramic semi-ring is installed on the rear side (yellow color). Half rings are made of normal thickness (2.310-2.360 mm) and increased (2.437-2.487 mm).
The axial clearance between the thrust half rings to the thrust surfaces of the crankshaft is checked as follows:
- place the indicator on the magnetic stand and insert the ends of two screwdrivers as shown in fig. 2-39;
- move the shaft with screwdrivers and check the axial clearance on the indicator, which should be in the range of 0.06-0.26 mm.
If the gap exceeds the maximum allowable 0.35 mm, replace the thrust half rings with others increased by 0.127 mm.
Note. The axial clearance of the crankshaft can also be checked on the engine installed on the vehicle. Using tool 67.8701.9510. In this case, the axial movement of the crankshaft is created by pressing and releasing the clutch pedal, and the value of the axial clearance is determined by the movement of the front end of the crankshaft.