Valve movement
Measure the gap "valve guide-stem" with a dial indicator when swinging the rod in the direction of normal axial pressure (oscillation method).
Clearance between intake valve stem and guide:
- Standard value: 0.04 - 0.10 mm
- Limit value: 0.16 mm
Clearance between exhaust valve stem and guide:
- Standard value: 0.10 - 0.16 mm
- Limit value: 0.22 mm
If the measurement still exceeds the limit value, replace the valve and/or valve guide if necessary.
Note: An additional method for checking the guide is to subtract the measured valve stem outside diameter from the measured valve guide inside diameter. Measure at three places along the length of the valve stem and three places inside the valve guide. The difference between the largest guide dimension and the smallest rod dimension must not exceed the limit value.
Clearance between intake valve stem and guide:
- Standard value: 0.02 - 0.05 mm
- Limit value: 0.08 mm
Clearance between exhaust valve stem and guide:
- Standard value: 0.05 - 0.08 mm
- Limit value: 0.11 mm
Cylinder head out of plane
Attention: If the gaps "distribution - holder" are not within specification, the cylinder head cannot be reground.
If the gaps "camshaft - holder" within the nominal value, check for flatness of the cylinder head.
- If the out-of-flatness is less than 0.05 mm, regrinding of the cylinder head is not required.
- If the flatness is between 0.05 mm and 0.2 mm, grind the surface of the cylinder head with a nougat block.
- The maximum value of non-flatness is 0.2 mm, with a height of 93 mm.
Take measurements in the directions shown in the figure.
Cylinder head height:
- Nominal value: 92.95-93.05 mm