In the lower part of the cylinder block, between the main bearing beds, there are nozzles for cooling the pistons. Loosen the screws that secure the oil nozzles and remove them (arrow, Fig. 4.86).
Before installation, measure the nominal clearance between the piston and the bore in the cylinder block, for which:
- measure the piston diameter with a micrometer at a distance "A" from the lower edge of the skirt in a plane at 90° to the axis of the piston pin (Fig. 4.87) and with a 90° offset in the horizontal plane.
- For "M62B44" the piston diameter should be 12.0 mm, and for "M62B46" - 21.5 mm;
- measure the diameter of the cylinder mirror in three planes with a micrometer (top, middle and bottom) and calculate the average value, which should be for "M62B44" within 91.976 - 91.994 mm, for "M62B46" - within 92.980 - 92.000 mm;
- subtract the piston diameter from the average cylinder diameter;
- the obtained value of the nominal gap should be within the range of 0.006 - 0.038 mm for "M62B44", and within the range of 0.006 - 0.034 mm for "M62B46";
- the maximum permissible value as a criterion for necessary repairs in case of wear of parts is 0.10 mm.
Compress the piston rings using the device "11.9.500" for the engine "M62V46" or the device "11.2.260" for the engine "M62V44". The tension band along the entire perimeter must fit tightly to the piston surface.
Replace the connecting rod bearing shells. Lubricate the connecting rod bearing shells with engine oil. Install the bearing cap so that the numbers for selecting the pair match on one side (see fig. 3.98).
Insert new clean connecting rod bolts, lightly lubricated with engine oil. Using tools "00.9.120" or "11.2.110" (torque wrench with protractor), tighten both bolts in three parallel steps on each bolt:
- 1st step, torque 5.0 Nm (0.5 kgf·m);
- 2nd step, torque 20 Nm (2.0 kgf·m);
- 3rd step, turn to an angle of 80°.
Continue assembling the engine in reverse order. If necessary, replace the piston cooling nozzle mounting screws. Cover the threaded portion of the bolts with a means to prevent them from loosening.