Withdrawal
1. Using a special tool, a wrench for the cylinder head bolts (09221—32001), remove the cylinder head bolts as shown in the figure.
2. Using a special tool, a clamp to compress the valve springs (09222—28000, 09222— 28100), remove the cracker. Next, remove the upper valve spring plate, valve spring, lower plate and valve.
Note. Keep these parts in the same order as they must be installed in their original positions.
3. Use pliers to remove the sealing cap. Do not reuse it.
Examination
Cylinder head
1. Check the cylinder head for cracks, damage and coolant leakage. If there are cracks, replace the head.
2. Completely remove scale, sealant and carbon deposits. After cleaning the valves, blow them out with compressed air to make sure they are not clogged.
3. Check the flatness of the cylinder head joint surface using a straight edge ruler set in directions A, B, etc. as shown in the figure. If deviations from the plane in any direction are outside the established limits, replace the cylinder head, or lightly process its surface.
- Deviation from the flatness of the surface of the cylinder head:
- Rated value - less than 0.05 mm
- Limit - 0.1 mm
Valves
1. Using a wire brush, thoroughly clean the valve.
2. Check each valve for wear, damage or breakage to the head and stem in area B. Repair or correct as necessary. If end A of the rod is worn out, resurface it. Restore also the surface of the working chamfer of the valve. If the valve edge height is less than the allowable limit, replace the valve.
Valve edge height | |
Nominal size | |
Inlet valve | 1.0 mm |
Exhaust valve | 1.5mm |
size limit | |
Inlet valve | 0.7 mm |
Exhaust valve | 1.0 mm |
Valve springs
1. Check the length of the spring in the assembled state and its extension. If it exceeds the allowable limits, replace the spring.
2. Check the parallelism of the ends of each spring. If it is out of specification, replace the spring.
valve springs | |
Rated value | |
Free Height | 48.3 mm |
Load | 300 N/40 mm |
End parallelism | 1.5°or less |
limit value | |
Free Height | 1 mm less |
Deviation from parallelism | 4° |
Valve guides
Check clearance between valve stem and bushing.
If it exceeds the specified limits, replace it with a bushing of the following size:
Clearance between valve stem and sleeve
Nominal size | |
Inlet valve | 0.020-0.047 mm |
Exhaust valve | 0.050-0.085 mm |
size limit | |
Inlet valve | 0.1 mm |
Exhaust valve | 0.15 mm |
Valve seat
Check the valve seat for signs of overheating and proper contact with the valve face. Repair or replace the valve seat if necessary. Before repairing the seat, inspect the valve liner for wear. If the bushing is worn, replace it and then repair the seat. Repair the valve seat using a valve seat grinder or cutter. The width of the contact band of the seat with the valve face must have a certain value, and the contact strip must be located in the center of the valve face.
Valve seat replacement procedure
1. An excessively worn valve seat should be replaced at normal temperature after cutting off most of the seat wall using a valve seat grinder as shown in fig. A.
Installation
Note:
- 1) Clean all parts before assembly.
- 2) Use engine oil to lubricate rotating and sliding parts.
1. After installing the lower spring plate, press the sealing cap onto the valve sleeve. Install the cap by gently turning the valve sealing cap installer. The sealing cap is installed in the desired position with a special tool. If the sealing cap is not positioned correctly, the protrusion of its inner hole may be eccentric and oil may leak into the valve sleeve. Do not rotate the cap when installing. Do not use old sealing caps.
2. Apply engine oil to each valve. Insert the valves into the sleeves, do not force the valve stem through the sealing cap. After installation, check that the valve can move freely.
3. Install the valve springs and their upper plates.
The valve springs must be installed with the varnished side towards the top plate.
4. Using a valve spring compressor, remove the crackers (tools 09222-28000 and 09222-28100, see picture). Remove the top poppet, spring, bottom poppet and valve.
Note. Keep these parts in the order in which they should be installed in their places.
5. Clear those surfaces of the block of cylinders and a head of cylinders which contact with a lining established between them.
6. Install a new gasket on the cylinder head. Do not apply sealing material to the gasket and do not use old gaskets.
7. Using a special tool, a wrench for tightening the cylinder head bolts (09221—32001), tighten the cylinder head bolts in the order shown in the figure.
- Torques: Cylinder head bolts (cold engine) — 90-100 Nm