Checking cylinder diameters
Make accurate measurements of cylinder diameters. Measurements to be made with a caliper in three belts as in the transverse direction «A», and in the longitudinal direction «B», as shown in the diagram in the section «EP, YP, YZ, DS, OT and DZ engines».
In cases where wear exceeds the allowable values by more than 0.08 mm, bore the cylinders to the nearest repair size and install pistons of the corresponding repair size.
Checking clearances between liners and crankshaft journals
Install the crankshaft to the cylinder block.
Thoroughly clean the running surfaces of the liners and the corresponding crankshaft journal. Put a piece of plastic calibrated wire, equal in width to the insert, on the surface of the neck.
Depending on the type of neck to be checked, install a connecting rod with a cap or a main bearing cap on the neck and tighten the fastening nuts or bolts, respectively. Tighten the nuts of the connecting rod bolts first to a torque of 3.0 kgf·m, then tighten by 90°, or the bolts of the main bearing caps to a torque of 6.5 kgf·m. Do not allow the crankshaft of the engine to rotate.
Carefully remove the cover and, using the scale printed on the package, determine the size of the gap by the flattening of the wire. More detailed information is given in the accompanying documentation of the gauge wire manufacturer.
The nominal design gap is 0.030-0.080 mm (maximum allowable 0.17 mm) for indigenous and 0.020-0.076 mm (maximum allowable 0.095 mm) for crankpins.
If the gap is greater than the limit, then replace the liners on these necks with new ones. If the crankshaft journals are changed and ground to a repair size, then replace the liners with repair ones (increased thickness).
Checking the axial clearance of the crankshaft
Check the axial clearance of the crankshaft using a feeler gauge on the third bearing, which should be no more than 0.20 mm.
If the gap is greater than the marginal one, and the main journal of the crankshaft is not ground, to ensure the desired axial movement of the shaft, liners with thrust collars of nominal size should be placed on the third support. If the main journals of the shaft are ground to the repair size, then for this purpose it is necessary to put liners of the corresponding repair size on the third support.
Checking the dimensions of pistons and piston rings
Determine the degree of piston wear by measuring the diameter of 15 mm from the edge of the piston skirt perpendicular to the axis of the piston pin (see photo in section «EP, YP, YZ, DT, DS and DZ engines»). The piston must be replaced if its diameter differs by more than 0.04 mm from the permissible values (see subsection «Design and specifications»).
Replace piston rings or pistons if the gaps between the piston rings and grooves exceed the wear limits (see subsection «Design and specifications»).
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