- Combustion chamber volume, cm3: 29,5-30,5.
- The total height of the cylinder head, mm: 81±0.25.
- When grinding, the height of the cylinder head can be reduced by no more than 0.5 mm.
Cylinder head gasket
Thickness of the cylinder head gasket, mm: 1.15-1.30.
The cylinder head gasket is installed with a label «Oben» or «Thor» («Top») towards the cylinder head.
Valve seats
The valve seats are integral with the cylinder head. Seat chamfer width, mm:
- inlet valve seats: 1.25-1.50;
- exhaust valve seats: 1.60-1.85.
Seat angle: 45°.
Valve guides
The valve guides are made directly in the body of the cylinder head.
Guide bushing hole diameter, mm:
- nominal: 7.025-7.045;
- 1st repair size, mark «1» (enlarged by 0.075 mm): 7,100-7,120;
- 2nd repair size, label «2» (enlarged by 0.150 mm): 7,175-7,195;
- 3rd repair size, label «A» (enlarged by 0.250 mm): 7,275-7,295.
Valves
The valves are located in the cylinder head in a row at an angle to the vertical axis of the cylinders and are actuated by the camshaft cams through pushers, rocker arms and rocker arms. The valves are made of special chromium steel. The exhaust valves have a reinforced working chamfer. Exhaust valves have rotary devices.
Clearances in the valve drive mechanism
The normal gap between the rocker arm and the end of the valve stem, measured with a feeler gauge on a hot engine, is 0.15 mm for intake valves, and 0.25 mm for exhaust valves.
Valve springs
Each valve is equipped with one spring. The characteristics of the intake and exhaust valve springs are the same.
Wire diameter, mm: 3.6.
Length of intake and exhaust valve springs, mm:
- with an open valve under a load of 45 kgf: 23.0:
- with the valve closed under a load of 15 kgf 32.5.
Valve characteristics
Valve lifters
The working ends of the pushers are thermally treated.
Pusher diameter, mm: 11.966-11.984.
Repair diameter of the pusher (enlarged by 0.15 mm): 12,116-12,134.
Gap between pusher and rod, mm: 0.016-0.052.
Rocker bars
The gas distribution mechanism uses short tubular rocker rods with spherical polished tips. Permissible bending of the rod, mm. no more: 0.20.
Rocker arms
The rocker arms are stamped from sheet steel; mounted on ball heads mounted on studs fixed in the cylinder head.
The working shoulder of the rocker, mm: 15.45.
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