Checking the axial play of the crankshaft
1. When checking the axial play of the crankshaft, the latter must be installed in the cylinder block, but at the same time be able to move freely (see paragraph 12).
2. Measure the axial play using a dial indicator, the tip of which rests against the end of the crankshaft. Move the crankshaft to the stop in one direction and set the device to zero. Move the crankshaft in the opposite direction and determine the value of the axial displacement. The result must be compared with the permissible value given in the technical data. Based on the comparison, it is possible to determine the need to replace the thrust washers (see fig. 15.2). Please note that all thrust washers must be the same thickness - refer to the Technical Data section to determine which washers are available.
Fig. 15.2. Checking the axial play of the crankshaft using a dial indicator
3. If you do not have a device, you can use flat feeler gauges. Move the crankshaft as far as it will go towards the flywheel/drive faceplate and use a feeler gauge to determine the clearance between the thrust washer and the crankpin cheek #3 of the crankshaft connecting rod journal on 4-cylinder engines, between cheek #4 and the thrust half ring on 5-cylinder engines, and between cheek #5 of the crankpin and the thrust half ring on 6-cylinder engines (see fig. 15.3).
Fig. 15.3. Checking the crankshaft play using a flat feeler gauge
Checking the status
4. Wash the crankshaft with kerosene or other suitable solvent and dry it well, preferably with compressed air. Pay special attention to ensure that all oil holes are well cleaned.
Warning: Protect your eyes when using compressed air!
5. Carefully inspect the main and connecting rod journals and make sure that there are no visible signs of wear, scoring, pitting or cracks.
6. Wear of the connecting rod journals is the cause of a noticeable metallic knock during engine operation, especially noticeable when accelerating from low speed, as well as a slight decrease in pressure in the lubrication system.
7. Wear of the main journals causes strong vibration of the engine, turning into a roar when the engine accelerates, and again, a decrease in pressure in the lubrication system.
8. Check for unevenness on the journal surfaces by running your finger over them without pressing. If there are large unevennesses and wear on the crankshaft journals, they must be ground down, if this is still possible, or the entire shaft must be replaced.
9. If the crankshaft has been ground, check for burrs around the crankshaft oil holes (usually oil holes have a chamfer, and if the grinding was done properly, there are no problems with burrs). Remove all burrs with fine sandpaper or a scraper and thoroughly clean the oil holes as described earlier.
10. Using a micrometer, measure the diameters of the main and connecting rod journals (see fig. 15.10) and compare the measurement results with the "Technical Data". By measuring the journal diameter at several points around the circumference, you can determine its ovality. To determine the taper of the journal, measure its diameters at the opposite cheeks. Compare the measurement results with the "Technical Data". If there is no data on the wear of the shaft journals in the "Technical Data" section, consult an engine repair specialist.
Fig. 15.10. Measure the crankshaft journal diameters with a micrometer
11. Check for wear or damage where the crankshaft contacts the sealing cups. If any of the cups have worn a deep groove in the journal, consult an engine repair specialist: is it possible to restore the shaft or does it need to be replaced.
12. On some models, if the crankshaft has not been ground, it is possible to restore the crankshaft and install oversize bearings (see paragraph 19). If there are no repair size liners and the crankshaft wear exceeds the limit set by the technical data, the only option left is to replace the shaft. Consult with specialists about what parts are currently available.