Mitsubishi 6M70 Workshop Manual page 61

• After refacing, make sure to lap the valve and valve seat.
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 thick-
ness, then remove the valve seat at room temperature.
[Installation]
• Measure the diameter of the valve seat hole in the cylinder
head.
• If the measurement deviates from the standard value, replace
the cylinder head.
• Chill the valve seat thoroughly by immersing in it in liquid nitro-
gen.
• Drive in the valve seat using
facing the cylinder head.
• After driving in, reverse the direction of
seat.
• After reassembly, make sure to lap the valve and valve seat.
Inspection: Cylinder head bottom surface distortion
• If the distortion exceeds the limit, rectify it using a surface grind-
er.
CAUTION
• Make sure that the height of the cylinder head from the top
surface to the bottom surface is not reduced to a value be-
low the limit.
11
with the chamfered side of
and crimp the valve
11-51