- Check the crankshaft for damage and measure the main and connecting rod bearing journals. Measurements to determine taper and ovality should be carried out in the directions indicated in Figure 100. To install a crankshaft with oversized bearing shells, the main bearing journals and connecting rod journals can be ground.
Pic. 100. Measuring the diameter of the connecting rod journal. Take measurements at the indicated location.
- Clamp the crankshaft in the centers of the lathe (or insert it with both outer outer pins into the prisms) and check the runout of the middle bearing journal using a dial indicator. For a full revolution, runout should not exceed 0.06 mm (Pic. 101). Otherwise, replace the shaft.
Pic. 101. Checking the crankshaft runout on the middle journal.
- Measure the play of the main and connecting rod bearings:
— Clean the bearing shells and place them in the cylinder block bearing beds or in the connecting rods.
— Place a piece of PLASTIGAGE plastic hair on all the main journals, as shown in Figure 102, and apply the main bearing caps with inserted liners. Tighten the bolts to a torque of 60 Nm. After this, the shaft cannot be rotated.
Pic. 102. Applying a PLASTIGAGE hair to the crankshaft journals.
— To check the play of the connecting rod bearings, place the connecting rods on the connecting rod journals and place a piece of PLASTIGAGE plastic hair on the upper side of the connecting rod journal. Place the bearing cap with the shell and tighten the nuts with a tightening torque of 50 Nm. Since the shaft cannot be rotated, two connecting rod bearings located at bottom dead center are used. If the shaft is removed for inspection, position the connecting rods so that after tightening they cannot rotate on their own.
— Install the main bearing caps; On the connecting rod bearings, unscrew both caps in sequence.
— Using the supplied PLASTIGAGE template, measure the widest part of the crumpled hair (Pic. 103). The play is normal if it is within the values specified in the size and adjustment table for the main and connecting rod bearings. If the wear limit is exceeded, new liners should be installed, and it is necessary to take into account whether the journals have already been ground, since there is only one repair size.
Pic. 103. Measuring the width of a crushed PLASTIGAGE hair when determining bearing play.
— If you are checking the play of the connecting rod bearings, rotate the crankshaft and measure the other connecting rod journals as described above.
- When selecting a new bearing, the following guidelines must be taken into account:
— If the play of the main bearings does not correspond to the specified values, you should check the numbering on the cylinder block. The number is stamped next to the corresponding main bearing and also characterizes the bearing size with numbers 1, 2 or 3. The same number is stamped on the rear surface of each bearing shell. Five different earbud sizes are available. Identify each bearing by its number. To replace, always use a bearing with the same number. If in doubt, contact a workshop.