The design of the cylinder head is shown in Figure 6.3. The nominal height of the engine cylinder head is factory-set and cannot be changed.
Permissible Warpage (flatness) mating surface of the head with the cylinder block in all directions, no more than - 0.03 mm.
Attention! Machining of the cylinder head and lapping of the seats are not allowed.
Guide bush inner diameter (nominal):
- intake valve - 6.0+0.015 mm;
- exhaust valve - 6.0+0.015+0.030 mm.
Camshaft bearing diameter - 23.0 mm.
Thrust bearing width - 18.85-0.08 mm.
The angle of the working chamfer of the valve seat is 45°.
Valve seat face width:
- intake valve - 1.45 mm;
- exhaust valve - 1.45 mm.
Checking the cylinder head for tightness is carried out using a set of tools, by immersing the head in a bath of water, at a test pressure of 4.5 bar (4.5 kgf/cm2) and controlled by the appearance of air bubbles.
Cylinder head gasket
Cylinder head gasket (1, fig. 6.3) designed to seal the junction of the head and engine block, made of synthetic materials (asbestos-free) with metal edging holes for cylinders.
The gasket is installed with a label «Oben» («Top») to the cylinder head. The thickness of the gasket is determined by the maximum amount of piston protrusion from the cylinder block. With a protrusion of the piston crown of 0.92–1.03 mm, install a gasket with 2 holes. With a larger protrusion (1.03mm) - a gasket with 3 holes.