Reassembly of the cylinder head is carried out in the reverse order of disassembly, taking into account the following:
- before installing the valves, lubricate the holes in the valve guides and valve stems with engine oil;
- before pressing the valve stem seals onto the valve guides, seal the cracker grooves on the valve stems with adhesive tape to protect the sealing edges of the valve stems from damage;
- valve springs are of the progressive spring type. Install the springs so that the most compressed coils of it (with color marking) rested on the cylinder head;
- install the upper spring plates and valve cotters, compressing the springs by installing a pressure frame (see subsection «Disassembly of the cylinder head») or universal tool for removing valve springs;
- insert the rocker shafts, paying attention to the correct position of the springs, rocker arms, support and adjusting washers (see photo). On models «518» And «520» pay attention to the fact that the hole in the axis of the rocker arms of the intake valves on the side of the rear end of the cylinder head remains open, and the hole in the axis of the rocker arms of the exhaust valves on the same side is closed with a plug (see photo). If the plug-plug is loose, it must be replaced; when installing a new plug-plug, apply Loctite AVX type sealant to the mating surfaces;
- on models «525» And «528» before installing the plugs of the oil distribution channels of the rocker arms, lubricate them with sealant such as Loctile No. 73;
- when installing the valve rocker axles, it is necessary to align the recesses in the axles with the holes for the cylinder head mounting bolts;
- install guide pins to prevent deformation of the rocker axles (see photo);
- install the pressure frame on the cylinder head, install the camshaft, making sure that the valve clearance eccentrics on the rocker arms are in the position corresponding to the maximum clearance, and lubricating the bearing journals and camshaft bearings with engine oil.
- install the protective cover and the ignition distributor bracket, replacing the gaskets (install only gaskets «Cobritol») and placing the retained sealing washer 1 (see photo);
- direct the central oil supply tube so that the oil jets hit the rocker shafts.