Cylinder head
1. Check the flatness of the surface of the cylinder head connector with the block. To do this, you must use a special ruler and a set of probes. Placing the ruler in the planes indicated in the figure, measure the non-flatness of the connector surface with probes.
Note: Standard surface non-flatness value: less than 0.05mm.
2. Check the combustion chambers, inlet and outlet passages and the surface of the connector with the cylinder block for damage. If any defects are found, replace the cylinder head assembly.
Valves, tappets, guide bushings and valve springs
1. Check the technical condition of the guide bushings and valves.
Using a bore gauge, measure the inside diameter of the valve guide as shown.
Note: Standard inner diameter: 5.500-5.512 mm
Using a micrometer, measure the outside diameter of the valve stem as shown in the illustration.
Note: The standard valve outer diameter is 5.465 ~ 5.480mm (inlet), 5.458 ~ 5.470 mm (high school graduation).
The difference between the inner diameter of the guide sleeve and the outer diameter of the valve stem is the clearance between the valve and the sleeve.
Note:
Standard value:
- Inlet: 0.020 - 0.047 mm.
- Exhaust: 0.030 - 0.054 mm.
Maximum allowable value:
- Inlet: 0.07 mm.
- Graduation: 0.09 mm.
If the gap is greater than the maximum allowable value, it is necessary to replace the valve assembly with the sleeve.
2. Check the technical condition of the valves.
Check the angle of sharpening of the working chamfer of the valve head.
Check the valve surface for excessive wear. If any defects are found, replace the valve with a new one.
Check the thickness of the valve head band. If the thickness of the valve head band is less than the maximum allowable, it is necessary to replace the valve with a new one.
Note: The standard value for the thickness of the girdle: 1.02 (inlet), 1.09 (high school graduation).
Measure the overall length of the valve.
Note:
- Standard valve length: 113.18 mm (inlet), 105.84 mm (high school graduation).
- Maximum allowable valve length: 112.93 mm (inlet), 105.59 mm (high school graduation).
3. Check the technical condition of the valve seats.
Check that the valve fits snugly against the seat, around its entire circumference. Replace valve seats if necessary
Before restoring the valve seats, it is necessary to check the technical condition of the valve guides. If any defects are found, it is necessary to replace the sleeve, and then carry out the restoration of the seat. The thickness of the contact surface of the seat with the valve must correspond to the standard value.
4. Check the technical condition of the valve springs.
Using a steel square, measure the amount of deflection from the vertical axis of the spring.
Note:
- Permissible deviation from the vertical axis: 1.5°.
- Maximum permissible deviation: 3°.
Using a caliper, measure the free length of the spring.
Note: Standard spring length: 47.44 mm.
Note: If the free length of the spring is not within the standard value, the spring must be replaced with a new one.
5. Using a micrometer, measure the outer diameter of the pusher.
Note: Standard value: 31.964 - 31.980 mm.
6. Using a compass, measure the inside diameter of the tappet hole in the cylinder head.
Note: Hole inner diameter: 32.000 - 32.025 mm.
7. Subtract the outside diameter measurement from the tappet inner diameter to determine the clearance.
Note:
- Standard value: 0.020 - 0.061 mm.
- Limit value: 0.07 mm.
Camshaft
1. Using a micrometer, measure the height of the camshaft cams.
Note: Standard jaw height: 44.10 - 44.30 mm (inlet), 44.90 - 45.10 mm (high school graduation).
Note: If the camshaft lobe height is less than the minimum, the camshaft assembly must be replaced.
2. Check up a backlash in bearings of a camshaft.
Clean and wash the bearing caps and camshaft journals.
Install the camshafts in the cylinder head.
Lay special plastic gauges on the camshaft journals, as shown in the figure.
Install the camshaft bearing caps.
Attention. Do not turn the camshaft.
Remove the camshaft bearing caps.
Measure the thickness of the plastic gauge (a scale is attached to the plastic gauge set). From this, determine the amount of clearance in the bearings.
Note:
- Standard bushing gap #1: 0.022 - 0.057 mm, #2, 3, 4, 5: 0.045 - 0.082 (inlet), No. 1: 0 -0.032 mm, No. 2,3,4,5: 0.045 - 0.082 (release).
- Maximum allowable: No. 1: 0.09 mm, No. 2,3,4,5: 0.12 mm (inlet); 0,12 (release).
Note: If the bearing clearance exceeds the allowable limit, the camshaft must be replaced. If necessary, replace bearing caps or cylinder head assembly.
Remove all plastic gauges.
Remove camshafts.
3. Measure the axial clearance of the camshaft.
Install the camshafts.
Using a dial gauge, measure the end play while moving the camshaft forward/rear.
Note:
- The standard value of the axial clearance of the camshaft: 0.04 ~ 0.16 mm.
- Maximum permissible value: 0.20 mm.
If the axial clearance exceeds the maximum allowable value, the camshaft must be replaced. If necessary, replace the camshaft bearing caps and cylinder head assembly.
Remove camshafts.
Exhaust camshaft bearing
1. Check up a label of an opening of a head of the block of cylinders.
Label location:
2. Select a bearing class the same as the cylinder head as shown in the table.
Label location:
Note: Oil clearance: 0 - 0.032 mm.
Mechanism for changing the valve timing assembly (phase shifter)
1. Check the technical condition of the valve timing mechanism assembly.
Check and make sure that the mechanism does not rotate.
Wrap all parts of the mechanism with vinyl tape except for the one shown in the picture below.
Inlet
Release
Wrap a special air gun, then apply a pressure of 150 kPa to the hole on the camshaft (when performing this operation, remove the lock pin).
Note: After splashing engine oil, wipe the surfaces with a rag.
While performing the above operation, turn the phase shifter assembly forward by hand (the direction is indicated by the arrow in the figure). When compressed air is supplied, the phase shifter must be moved in the advance direction without effort, by hand, except for the position when the locking pin reaches the maximum deviation in the retard direction.
After that, turn the phase shifter back. Check the smoothness of its movement, excluding jamming.
Note: The range of movement of the phase shifter is 22.5° (inlet), 20° (release).
Turn the phase shifter assembly by hand and fix it in the limit position of the delay.