Attention! Valves cannot be processed (turning or grinding). Only lapping of valves is allowed.
Valve sizes
Inlet valve | Exhaust valve | |
Diameter a | 29.5 mm | 26.0 mm |
Diameter b | 5.973 mm | 5.953 mm |
Length with | 100.9 mm | 100.5 mm |
Angle α | 45° | 45° |
Valve seat processing
Attention!
- When repairing engines with leaking valves, it is not enough to replace the valves or remake the valve seats. It is also necessary, especially for engines with high mileage, to check the wear of the valve guides.
- The valve seats must be machined until a perfect conical sealing surface is obtained.
- Before starting work, you should calculate the maximum allowable allowance for processing. Exceeding the maximum allowable machining allowance leads to disruption of the normal operation of the hydraulic lifters. In this case, the cylinder head will need to be replaced.
You can calculate the maximum allowable machining allowance as follows.
1. Install the valve in the guide sleeve and press it firmly against the seat.
Attention! If the valve is to be replaced during repair, a new valve should be used for measurement.
2. Measure the distance between the end of the valve stem and the top edge of the cylinder head.
3. Calculate the maximum allowable machining allowance based on the measured distance and the minimum allowable size.
Minimum dimensions
Inlet valve: 7.6 mm.
Exhaust Valve: 7.6mm.
The difference between the measured distance and the minimum size is equal to the maximum allowable machining allowance.
Example of calculating the allowance for processing valve seats
Measured distance | 8.0 mm |
Minimum size | 7.6 mm |
Maximum allowable machining allowance | 0.4 mm |
Inlet valve seat processing
Size | Value for inlet valve seat |
Diameter a | 28.7mm |
Maximum allowable machining allowance b | Estimated value |
Width of the closing surface of the valve with | 1.5. 1.8mm |
Valve seat angle α | 45° |
Top bevel angle β | 30° |
Angle of bottom corrective chamfer γ | 60° |
Exhaust valve seat processing
Size | Exhaust valve seat value |
Diameter a | 25.0 mm |
Maximum allowable machining allowance b | Estimated value |
Width of the closing surface of the valve with | approx. 1.8mm |
Valve seat angle α | 45° |
Top bevel angle β | 30° |
Angle of bottom corrective chamfer γ | 60° |
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