3.1. Head of cylinders and mechanism of gas distribution

The head of cylinders is cast from aluminum alloy, has combustion chambers of a wedge-shaped form, the pressed saddles and the directing plugs of valves. Saddles of valves are made of special cast iron for ensuring high durability at influence of shock loadings. Working facets of saddles are processed after a press fitting assembled with a head of cylinders to provide exact coaxiality of facets with openings of the directing plugs of valves.

The directing plugs of valves are also manufactured of cast iron and pressed in a head of the block of cylinders with a tightness. On the external surface of the directing plugs there is a pro-point where the lock ring is inserted. It provides the accuracy of position of plugs at a press fitting them in a head of cylinders and protects plugs from possible drop-out.

Openings in plugs are processed after their press fitting in a block head. It provides the narrow admission on diameter of an opening and accuracy of its arrangement in relation to working facets of a saddle and the valve. In openings of the directing plugs there are spiral flutes for lubricant. At plugs of inlet valves of a flute are cut to a half of length of an opening, and at plugs of final valves – on all length of an opening.

From above maslootrazhatelny caps from heatoilproof rubber with a steel reinforcing ring are put on the directing plugs. Caps cover a core of the valve and serve for reduction of penetration of oil into the combustion chamber through gaps between the directing plug and a core.

Valves are put in action by the camshaft rotating in the case of bearings via intermediate levers. The gap between cams of the camshaft and the lever is established by an adjusting bolt on which spherical head the lever shakes. From a samootvorachivaniye the bolt is kept by a lock-nut.

Valves have two cylindrical springs – external and internal, clamped between a plate (above) and two basic washers (below). The plate of springs is kept on a valve core by two crackers having the form in folded form of the truncated cone. Each lever nestles on a valve end face a special (shpilechny) spring.

For increase in wear resistance of a core both valves are nitrated, and end faces of cores on which levers lean are tempered by current of high frequency.

Camshaft cast, pig-iron, identical to all models of engines. Leans on 5 necks and rotates in the aluminum case of bearings installed on a head of the block of cylinders. To a forward end face of the camshaft the conducted asterisk fastens. The camshaft refrains from axial movements by the persistent flange placed in a pro-point of a forward basic neck of a shaft.

The drive of the camshaft is carried out by a two-row roller chain from the leading asterisk of a bent shaft. The same chain gives also the roller of the drive of auxiliary units. The semi-automatic natyazhitel with a boot and an uspokoitel of a chain with plastic slips has the chain drive. In the lower part of the block of cylinders the restrictive finger preventing falling off of a chain in a case at removal (on the car) camshaft asterisks is established.

For the correct relative positioning of asterisks, i.e. for installation of phases of gas distribution there are top and lower adjusting tags. Top the lower tags – on an asterisk of a bent shaft and a cover of the drive of the camshaft are located on an asterisk of the camshaft and the case of bearings.