2.6.2. Check of a cranked shaft

Check of a cranked shaft is necessary for spending as follows:

- Carefully to check up cranked a shaft on possible presence of defects, to measure necks of radical bearings and a neck of bearings of rods. Necks of radical bearings of a cranked shaft and шатунные can be ground necks of a cranked shaft of about three times, therefore the shaft can be established with loose leaves of bearings, smaller in the sizes. It is necessary to remember that necks of radical bearings of the engine in volume have of 1,0 l the same diameter, as necks for other engines, but diameter шатунных is less than necks of a cranked shaft approximately on 6,0 mm. More detailed data see "Specifications";

- To clamp a cranked shaft centre to centre (or to establish both external necks of bearings on prisms) and on a neck of the central bearing with the help стрелочного the indicator to check up on palpation which should not exceed 0,06 mm. Otherwise to replace a shaft;

- To measure a working backlash in radical bearings and bearings of rods as follows:

1) carefully to clear loose leaves of bearings and to insert them into channels of the block of cylinders and in rods;

2) to establish on each neck of radical bearings on round plastic core Plastigage and to establish covers of radical bearings with the enclosed loose leaves. To tighten bolts the moment 65 Нм. At installation bolts should be tightened for 90 , but at measurement of a backlash of it it is impossible to do. After that a shaft not to rotate;

3) for check of a working backlash of bearings of rods to get a rod on шатунную a neck of a cranked shaft and to put plastic strips Plastigage on the top party шатунной necks of a cranked shaft. To establish a cover of the bearing with the loose leaf and to tighten nuts and bolts the moment of the inhaling equal 30 Нм. And in this case not to spend the further tightening on 90 . As further it is impossible to turn a shaft, the given operation is spent according to two bearings of rods which are in НМТ;

4) to turn on covers of radical bearings; at bearings of rods to turn on serially both nuts;

5) to measure by means of a template being in complete set Plastigage in the widest place the size of strip Plastigage deformed under pressing (fig. 79 see). If the given size does not fall outside the limits 0,03–0,08 mm it is necessary to use new loose leaves of bearings, having checked up, whether earlier repair grinding of necks was spent. Bearings of rods here too have distinctions. For the engine in volume of 1,0 l the working backlash makes 0,010–0,047 mm, for other engines — 0,006–0,047 mm. Maximum permissible deterioration is specified in "Specifications";

Fig. 79. Measurement of deformed plastic core Plastigage by means of a template

6) at check of a working backlash of bearings of rods to turn a cranked shaft and to perform the given operation for two other necks of bearings of rods with the same gaugings as it is described above.