Removing
1. Remove cylinder head covers (see Section Removal and installation of covers of heads of cylinders).
2. Moving from the ends to the middle, loosen the bolts securing the rocker axles in two or three steps.
Attention! Part of the valves, when the fasteners of the rocker axles are loosened, will remain open, as a result of which the axles will be subjected to the forces developed by the valve springs, and a sharp release of the mounting bolts can lead to deformation of the components.
3. Before removing the rocker arm assemblies from the engine, they should be clearly marked.
4. Turn out the weakened fixing bolts and alternately take from a head of assembly of axes with yokes. Lay the removed assemblies on the workbench, arranging them in the same way as they were installed in the engine. When assembling, all axles must be installed strictly in their original places in their cylinder heads. Please note that axles with deep samples are installed on the side of the inlet pipeline, with small ones - on the side of the exhaust manifolds.
Examination
1. Having removed the rocker arm assemblies, it would be wise to disassemble them in order to examine the condition of the components in more detail. Thoroughly clean the parts and check them for signs of wear and damage. Assess the condition of the surfaces of the rocker arms in contact with the camshaft. Check for nicks and signs of excessive wear on the rocker arm seat surfaces on the axles, as well as the walls of the rocker arm mounting holes. Defective components must be replaced.
2. Measure the outer diameters of the necks of the axes of the rocker arms. Record the measurement results and compare them with the requirements of the Specifications.
3. Measure the inner diameters of the rocker arm mounting holes. Also compare the results with the requirements of the Specifications.
4. By subtracting the results of the first measurements of the results of the second, determine the size of the landing clearances of the rocker arms on the axles. Compare the calculation results with the requirements of the Specifications. If necessary, replace excessively worn components.
Installation
Installation is in the reverse order. Tightening the bolts for fastening the rocker axles with the required force should be carried out in several stages in the direction from the ends of the assemblies to their centers.