11 Replacement of valve seat [Removal] • The valve seats are installed by expansion fitting. To remove a valve seat, grind inside the metal stock to reduce the wall thickness, then remove the valve seat at room temperature.
[Installation] • Check that the diameter of the valve seat hole in the cylinder head conform with the value shown below. Valve seat hole diameter
φ38
+0.025 0
mm {φ1.50
+0.00098 0
in.}
• Replace the cylinder head if the measurement deviates from specification.
• Chill the valve seat thoroughly by immersing in it in liquid nitrogen. • Install the valve seat in the cylinder head using and , with the chamfered edge of toward the valve seat. • Turn over so that its chamfered edge is toward , and calk the valve seat. • Lap the valve seat and valve.
Inspection: Cylinder head bottom surface distortion • If the distortion exceeds the specified limit, rectify it using a surface grinder.
CAUTION • When grinding the cylinder head bottom surface, make sure that the height of the cylinder head (from the top surface to the bottom surface) is not reduced to a value below the specified limit.
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