Position the cylinder block so that its bottom is facing up.
Unscrew the main bearing cap mounting bolts and lay them out so that they can be reinstalled in their original location later.
Remove the main bearing shells from the covers and cylinder block, if they are still in place. Wipe the surfaces of the lower and upper earbuds with a clean, lint-free cloth. These parts must be kept completely clean.
Clean the outer surface of the new main bearings and place them into the cylinder block seats. Place the corresponding mating inserts into the lids. Make sure the tab on the insert aligns with the notch on the block or cover.
In addition, the oil passage hole in the block must be aligned with the lubrication hole in the bearing. It is not allowed to install the liner in place by hammering or making scratches. At this stage, there is no need to lubricate the liner.
The insert with flanges must be installed in socket No. 3.
Wipe the working surfaces of the bearings in the block and the main journals of the crankshaft with a clean, lint-free cloth. Check or clean the crankshaft oil passages, as the only way for any contaminants to escape is through the new bearings.
Once you are absolutely sure that the shaft is clean, carefully place it in place on the main bearing shells (it is recommended to perform the operation with an assistant).
Before final installation of the shaft, it is necessary to check the lubrication clearance in the main bearings.
Figure 3.51. Position of a calibrated plastic rod section when measuring the crankshaft main bearing clearance
Prepare several pieces of calibrated plastic rod, the length of which is slightly less than the width of the main bearings, and place one piece on each main journal of the crankshaft parallel to its axis (figure 3.51).
Clean the surfaces of the liners in the lids and install the lids in place (don't confuse them) so that the arrows point towards the front of the engine. Do not touch the plastic rods.
Tighten the cover mounting bolts in three stages to the required torque, starting from the central bearing and continuing towards the ends of the shaft. When performing this operation, rotation of the shaft is not allowed.
Loosen the cap bolts and carefully lift the main bearing caps. Arrange the covers in the order that corresponds to their installation location. It is not permissible to disturb the position of the rods and rotate the crankshaft. If the cover is difficult to remove, loosen it by lightly tapping it on the side with a soft-faced hammer.
Figure 3.52. Using the scale printed on the packaging to measure the width of a deformed calibrated plastic rod
Compare the thickness of each of the deformed plastic rods with the scale on the packaging and determine the size of the gap (figure 3.52). Compare with the required value.
If the clearance is not as specified, recheck to ensure the correct size main bearings are installed. Also, make sure there is no contamination or oil between the bearings and the mounting surfaces when measuring.
Carefully remove any remaining plastic rod from the crankshaft journals and/or main bearing surfaces. Avoid damaging main bearing surfaces.
Carefully remove the crankshaft from the cylinder block. Clean the main bearing surfaces and apply a thin, even coat of high-quality molybdenum disulfide grease or engine assembly oil to each bearing. Be sure to lubricate the surfaces of the shaft thrust flanges and the friction surface of the thrust bearing.
Make sure the crankshaft journals are clean, then install the shaft into the cylinder block. Clean the bearing surfaces of the caps and apply a thin coat of molybdenum disulfide grease to each bearing surface. Install the covers back into place with the arrows pointing towards the front of the engine. Install the bolts and tighten them to the specified torque, starting from the center bearing and moving towards the ends of the shaft. Tighten the bolts in three stages.
Figure 3.53. Using a drift and hammer to install the pilot bearing into the end of the crankshaft
On models with an automatic transmission, install a new pilot bearing into the end of the crankshaft. Lubricate the shaft cavity and the outer surface of the bearing with clean engine oil, install the bearing. The bearing is seated by lightly striking the mandrel with a hammer (figure 3.53). Apply grease to the bearing.
Turn the crankshaft by hand several times – the shaft should rotate without noticeable jamming.
At the final stage, check the axial play of the crankshaft using a dial indicator.