Technical data
1. Cylinder head
Cylinder head height, mm:
- nominal H = 118;
- repair H = 117.8.
Maximum permissible deformation of the mating surface, mm: 0.05.
Combustion chamber volume with valves and spark plug, cm³: 27.68 ±0.65
Maximum permissible difference in volume of combustion chambers in one head, cm³: 0.8.
2. Valve guide bushings
Inner diameter, mm: 6+0,18.
Outer diameter of guide bushing, mm:
- nominal: 11:
- repair: 11.2.
Caution! The intake and exhaust valve guides have valve stem oil seals that must be replaced each time the valve drive mechanism is disassembled.
Inclination of the intake and exhaust valve guide bushings: P = 17.50°.
Position of the guide bushings of the intake and exhaust valves relative to the lower support ends of the valve springs, mm: A=15 ±0.15.
3. Valve springs
Length in free state, mm: 43.
Length under load, mm:
- 240 N ±1.35 37;
- 483 N ±3 31
Length of the spring with fully compressed coils, mm: 25.6.
Wire diameter, mm: 3.90
Inner diameter, mm: 20.2.
4. Valves
Rod diameter, mm:
- inlet valve: 5.98-0,015
- exhaust valve: 5.97-0,015
Working chamfer angle:
- inlet valve: 120°;
- outlet valve: 90°.
Head diameter, mm:
- inlet valve: 32.88 ±0.12;
- exhaust valve: 29.88 ±0.12.
5. Valve seats
Working chamfer angle:
- inlet valves α = 120°,
- exhaust valves α = 90°.
Width of working chamfer of seat, mm:
- intake valves X = 1.7 ±0.1;
- exhaust valves X = 1.7 ±0.1.
Outer diameter of seat D, mm:
- intake valves 33.5+0,05+0,034;
- exhaust valves 30.5+0,05+0,034.
6. Camshaft:
- axial clearance, mm: 0.07-0.148;
- number of bearings: 5.
7. Parts that must be replaced when removed:
- all sealing cuffs gaskets;
- valve guide bushings;
- camshaft pulley mounting bolt;
- cylinder head mounting bolt.
Disassembly
1. Remove the cylinder head (see section "Cylinder head gasket").
2. Remove the rocker arm mounting bolts and the rocker arm shaft, having first marked the position of the rocker arms on it.
3. Remove:
- camshaft toothed pulley.
- camshaft oil seal using tool Mot. 1381.
4. Loosen the camshaft thrust flange mounting bolts.
5. Remove the camshaft.
6. Remove the thermostat housing.
7. Remove the spark plugs.
8. Remove the valve springs using a special tool.
9. Remove the crackers, upper spring plates, valves, valve stem oil seals using special pliers Mot. 1335.
10. Clean the cylinder head and check the mating surface for deformation (see section "Cylinder head gasket").
Grinding valve seats
Inlet valves X = 1.7 ±0.1; α = 120°.
Grind the working chamfer of seat 1 using a cutter with an angle of 31°, reduce the width of the working chamfer by processing chamfer 2 with a cutter with an angle of 75° until a width of X is obtained.
Exhaust valves X = 1.7 ±0.1; α = 90°.
Grind the working chamfer of seat 1 using a cutter with an angle of 46°, reduce the width of the working chamfer by processing chamfer 2 with a cutter with an angle of 65° until width X is obtained.
Attention! Check the valve fits correctly to its seat (figure 2.45).
Assembly
1. Insert new valves 3 and lightly grind each valve to its seat.
2. Wash all parts thoroughly and label them, then proceed with assembly.
2. Lubricate all parts with engine oil.
3. Place new valve stem seals 5 on the valve guide bushings 2.
4. Install new valves 3, springs 4 one by one (the same for intake and exhaust valves) and top plates 6
5. Compress the springs.
6. Install crackers 7 (the same for intake and exhaust valves).
Note: Screw new studs 1 into the cylinder head and apply one drop of sealant.
Loctite Frenetanch. New cylinder heads are supplied by the spare parts warehouse complete with valves.
7. Check the condition of the roller surfaces and rocker arm bolts. Make sure that the lubrication holes of the rocker arm cams and heels are not clogged. Replace worn parts. Install the rocker arm shaft so that the E mark faces the timing gear.
8. Lubricate the camshaft with engine oil. Install the shaft into the cylinder head. Put the camshaft thrust flange in place and secure it with the locking plate (without applying Loctite sealant to its mounting bolts).
9. Install the magnetic bolt tightening device.
10. Make sure that the axial clearance does not exceed 0.07-0.148 mm.
11. Remove the thrust flange retaining plate mounting bolts, apply one drop of Loctite Frenetanch to each bolt, then replace and tighten the bolts.
12. Install the oil seal using tool Mot.1356. This tool allows you to shift the contact points of the working edge of the oil seal on the camshaft.
13. Install the thermostat assembly. Apply Loctite 518 to flange 1 and to the thermostat housing located on the cylinder head.
