The piston clearances in the cylinders must be selected according to the values given in the subsection devoted to pistons.
The cylinder surface smoothness should be 3-4 R ₁. The liners should be selected according to the sectional groups of the crankshaft journal diameters. The liners should be inserted into the bearing holes dry. In this case, it is necessary to ensure that ideal cleanliness is maintained. In order to measure the clearance in the crankshaft bearings, it is necessary to lay the shaft in the bearing holes in the engine housing and not turn it. To measure the clearance, use "Plastigage" strips, which should be placed in the axial direction on each journal of the shaft. After this, install the bearing caps with the liners and, using old bolts, screw them in the following way:
- 1.1 engine - torque 88-102 Nm.
- 1.4i/1.6i engine with torque of 90-100 Nm.
- diesel engine 1.8
- Stage I - torque 24-30 Nm
- Stage II - turn the bolts 45°
Note: The crankshaft must not be rotated. Otherwise, you will get erroneous measurement results.
Remove the bearing caps and measure the "Platigage" strips as shown in Fig. 2.79. If the bearing clearances are correct, the measurement results should be within the following limits:
- engine 1.1 - 0.009-0.046 mm.
- 1.4i engine - 0.011-0.058 mm.
- diesel engine 1.8 - 0.015-0.062 mm.
Before installing the crankshaft in the engine housing, lubricate it thoroughly. Use new bolts to secure the main bearing caps. Be sure to check the ease of rotation of the shaft in the bearings. If you feel uneven rotation, you will have to loosen the main bearing caps one by one until you find the bearing causing this defect. Determine the cause of the defect and eliminate it. If, despite the fact that the clearances in the bearings are correct, the shaft nevertheless rotates unevenly, the cause is most likely a curvature of the interacting parts. In this case, you will need the help of specialists from a service workshop that has special equipment for taking measurements.