2.2.2 Measurement of valve guide inside diameter
Use an inside micrometer to measure inside
diameter of the guide.
Fit clearance between intake valve stem and valve
guide: 0.012~0.043mm
Fit clearance between exhaust valve stem and valve
guide: 0.032~0.063mm
Note:
If abnormal noise is generated due to
serious wear of valve guide, do not replace the valve
guide, because the assembly technique requirements to
valve guide is very strict; please replace the cylinder head
assembly.
2.3 Boring and grinding valve seat insert
2.3.1 Inspection of fitting surface of valve. Apply a
circle of red lead on the valve sealing strip and then
gently place the strip onto the valve seat insert,
softly and forcibly press it down, but do not turn it.
Take out the valve, observe if there is broken part on
the red lead, if any, boring and grinding the valve
seat insert is required.
2.3.2 Select an appropriate reamer, use 45° conical
surface as cooperate standard value to check valve
cooperation position: the optimal position is the
center of the valve, if not so, be sure to revise. Cut
on the conical surface 70° inward and 30° outward
at the center of the cooperation position.
2.3.3 Perform seat grinding for the valve sealing
strip with polishing compound
Measurement point
