Note:
- Standard crankshaft axial clearance: 0.08-0.29 mm.
- Maximum permissible axial clearance of the crankshaft: 0.30 mm.
Dimensions of thrust half rings:
- Standard size: 2.500-2.550 mm.
- Repair size +0.25: 2.625-2.675 mm.
2. Using V-blocks and a dial indicator, measure the runout of the crankshaft main journals. If the measured value exceeds the maximum permissible value (0.10 mm), replace the crankshaft with a new one.
3. Check the diameter of the main and connecting rod journals of the crankshaft in four positions - in two directions (X and Y) at two points (A and B), as shown in the figure. If the measured values are not within the norm or if the ovality value (difference between X and Y values) exceeds the maximum permissible value, bore the crankshaft journal to the repair size.
Note:
- Standard main journal diameter: 49.980-50.000 mm.
- Maximum permissible ovality of the main journal: 0.005 mm.
- Standard crankpin diameter: 49.980-50.000 mm.
- Maximum permissible ovality of the connecting rod journal: 0.005 mm.
4. Check the oil clearance of the camshaft main journal:
- Install the thrust half rings, upper main bearing shells and crankshaft into the cylinder block.
- Place the round feeler gauge onto the neck.
- Install the lower main bearing shell and the lower part of the cylinder block.
- Tighten the lower cylinder block bolts.
- Loosen the bolts and remove the lower part of the cylinder block.
- Measure the oil clearance in the main bearing using the most flattened part of the round feeler gauge. If the measured value exceeds the maximum permissible value, replace the main bearing shell or bore the main journal and use repair-size bearing shells to ensure the required oil clearance.
Note:
- Standard crankshaft journal oil clearance: 0.016-0.039 mm.
- Maximum permissible oil clearance of the crankshaft main journal: 0.084 mm.
Dimensions of main bearing shells:
- Standard size: 2.489-2.510 mm.
- Repair size +0.25: 2.614-2.617 mm.
- Repair size +0.50: 2.739-2.742 mm.