Table of contents: Cylinder head gasket ↓ Valve seats ↓ Valve guide bushings ↓ Valves ↓ Clearances in the valve drive… ↓ Valve springs ↓ Pushers ↓
The cylinder head is cast from aluminum alloy. The valve seats and guides are pressed into the cylinder head.
Warpage of the mating plane of the connector head with the cylinder block, no more than, mm: 0.1.
Permissible height of the cylinder head after grinding, not less than, mm: 132.75.
Cylinder head gasket
There are no special markings on the cylinder head gasket for orientation; place the marks on the gasket towards the plane of the cylinder head.
Valve seats
Valve seats are non-removable. If there are traces of burning or wear that cannot be removed by grinding, the cylinder head must be replaced as an assembly with the seats.
Valve seat characteristics
Valve guide bushings
The valve guides are made of special brass and pressed into the cylinder head.
Permissible clearances between the end of the valve stem and the edge of the guide sleeve, mm:
- for intake valves: 0.10;
- for exhaust valves: 0.13.
Valve guide hole diameter, mm 8.013-8.035.
Valves
The valves are located in the head parallel to the cylinders vertically and are actuated directly by the camshaft cams through the tappets. The exhaust valves are not subject to grinding.
Valve characteristics
* 8 brackets indicate values for the engine model "NF".
Clearances in the valve drive mechanism
Engines of models "WH", "KR", "WC", "RT"
The clearance between the camshaft cams and the adjusting washers at a coolant temperature above 35°C should be 0.25±0.05 mm for the intake valves and 0.45±0.05 mm for the exhaust valves; on a cold engine, 0.20±0.05 and 0.40±0.05 mm, respectively.
The gap is adjusted by selecting the thickness of the adjusting washers installed on the upper ends of the pushers.
Spare parts include adjusting washers with a thickness of 3.00 to 4.25 mm at intervals of 0.05 mm.
Engines of the models "KU" and "NF"
The clearances in the valve drive mechanism are adjusted automatically by hydraulic tappets.
Valve springs
Each intake and exhaust valve has two springs. The springs are the same for both intake and exhaust valves.
Pushers
The valve tappets are located directly in the cylinder head. Adjusting washers of different thickness are installed on the upper ends of the tappets to adjust the thermal clearances of the valves, except for the engines of the "KU" and "NF" models.
The original article is located on the online resource: Audimanual.ru