Checking the end play
1. To measure the end play, the crankshaft must be in its place in the main bearings, but free in the axial direction.
2. Install a pointer indicator at the end of the shaft and rest its probe against the end of the shaft (pic. 13.2). Slide the shaft to one side until it stops and reset the indicator. Now slide it to the other side until it stops and read the indicator reading. This is the axial play. Compare the result with the regulated backlash value (see technical data) and decide if the thrust bearing needs to be changed.
3. If you do not have a dial indicator, then you can measure the backlash with flat probes. Slide the shaft towards the flywheel and measure the clearance between the crankshaft web and the thrust bearing (pic. 13.3).
Status check
4. Wash the crankshaft in kerosene or other suitable solvent. Dry the shaft, preferably with compressed air if possible. Clean oil holes.
Attention! Wear protective goggles when working with compressed air.
5. Inspect the main and connecting rod journals for excessive wear, scratches, nicks, pitting, and cracks.
6. The wear of the bearings of the lower heads of the connecting rods announces itself when the engine is running with a clearly distinguishable metallic knock (especially when accelerating the engine from low speeds), as well as some drop in oil pressure.
7. The wear of the main bearings is accompanied by a strong vibration of the engine and a roar, especially strong during acceleration of the engine, as well as a drop in oil pressure.
8. Slide your finger along the neck with light pressure - if grooves have developed on the neck. You can easily feel them. In this case, the shaft must be machined (if it's still possible) or replace.
9. After turning the necks, check for burrs on the edges of the oil holes. Usually the ends of the holes are chamfered, so burrs are unlikely to cause any problems if the groove is done carefully. Burrs can be removed with a scraper or fine file.
10. Entrust the groove of the necks to the specialists of the service station. They will pick up new liners of the repair size.