Attention! Description applies to standard size connecting rod bearings only. Repair connecting rod bearings are not divided into size groups.
New connecting rod bearings are selected according to the size group codes printed on the crankshaft.
Codes of size groups are applied on the 1st or 4th cheeks of the crankshaft.
To select the connecting rod bearing shells, you need to find out the size group of the crankshaft crankpin for a given cylinder, and then, using the attached table, determine the desired liner, guided by the color marking, which is applied in the form of a dot on the side surface of the liner.
crankshaft code | Color marking of the dimensional group of the liner |
0 | white (or missing) |
1 | brown |
2 | green |
Checking clearance in connecting rod bearings
1. Clean the outer surface of the connecting rod bearings and the surfaces of the bearing bores in the connecting rods and in the connecting rod caps.
2. Insert on the shells and make sure that the tabs on the bearing shells are in the grooves in the connecting rod (arrow) and in the cap of the connecting rod.
3. When installing the inserts, do not touch the work surface. Make sure the lubrication hole in the upper connecting rod is aligned exactly with the hole in the connecting rod.
4. If the clearance check will be performed with old liners, then insert these liners in their original places.
5. The clearance in the connecting rod bearings can be checked in two ways.
6. When determining the clearance in the first way, assemble the covers with connecting rods and connecting rod bearings, making sure that the relative orientation of these parts is correct.
7. Tighten the cap nuts to the specified torque and measure the inside diameter of each assembled pair of bushings. The clearance is defined as the difference between the inner diameter of the assembled connecting rod bearings and the diameter of the connecting rod journal.
8. Second way (more accurate) consists in the use of a plastic gauge wire.
9. Install the connecting rod bearings with the correct orientation. Place a piece of gauge wire on each connecting rod journal of the crankshaft.
10. Clean the connecting rod bearing surfaces and install the connecting rods on the corresponding crankshaft journals. Install the connecting rod bearing caps, orienting them according to the existing marks, or the marks made during disassembly.
11. Tighten the cap nuts. When tightening, changing the position of the wire is not allowed, and turning the crankshaft is also not allowed.
12. Remove the connecting rod caps without allowing the crankshaft to rotate or the gauge wire to move. Compare the flattened wire width to the scale on the package and determine the clearance in the main bearings.
13. If the clearance differs from the standard, then the reason may be the wrong selection of connecting rod bearings (or their increased wear if used liners were checked).
14. Before concluding that the bearings need to be replaced, make sure that there is no dirt or oil between the surfaces of the caps or connecting rods and the bearing when measured.
15. If the width of the flattened wire from one edge is greater, then this indicates a tapered crankpin.
16. If the clearance differs from the norm when measuring with old liners, then repeat the measurements with new liners.
17. If, with new liners, the gap exceeds the norm, then you should seek advice from a car service. It may be necessary to regrind the connecting rod journals of the crankshaft and replace the liners with repair ones.
18. If necessary, purchase liners of the appropriate size group and repeat the procedure for measuring the clearance in the connecting rod bearings.
19. When finished, carefully remove the remaining wire.
Installing the connecting rod and piston group
The following description is based on the assumption that the crankshaft has already been installed.
1. Make sure the connecting rod bearings are installed correctly.
2. If new bearings are installed, wash them in kerosene.
3. Wipe the connecting rods and bearings dry.
4. Lubricate the cylinders, pistons and rings, then lay out the pistons and connecting rods in the order in which these parts will be installed on the engine.
5. Start the assembly from the 1st cylinder. Make sure the piston rings are properly aligned (see subsection 3.1.2.13) and squeeze the rings with a special tool.
6. Insert the piston and connecting rod assembly into the first cylinder. Orient the piston so that the mark on the piston crown (in the form of an arrow or a dash) facing towards the front cover. Tap the piston lightly with a hammer handle or a wooden block so that the piston enters the cylinder and the piston bottom is level with the split plane of the cylinder block.
7. Make sure the connecting rod bearings are installed correctly and generously lubricate the bearing shells and the crankshaft journal.
8. Being careful not to damage the cylinder surface, tighten the connecting rod to the crankshaft journal.
9. Install the connecting rod cap with bushing and hand-tighten the nuts. Keep in mind that the planes on the connecting rod and on the connecting rod cap, which are labeled, must be aligned (this means that the locating lugs of the connecting rod bearings are opposite each other).
10. Tighten the connecting rod cap nuts to 1st stage torque using a torque wrench and socket. Then tighten the nuts to the angle of the 2nd stage of tightening, or tighten with the torque of the 2nd stage.
11. Check the freedom of rotation of the crankshaft. If new parts are installed, then there should be a noticeable constant resistance to the rotation of the crankshaft, however, the crankshaft should turn smoothly, without jamming.
12. Install the rest of the pistons and connecting rods in the same way.
13. Install the cylinder head, camshaft chains and oil pan.