Mitsubishi 4G1 Service Manual page 103

Free height
Guide O.D.
Intake
Exhaust
ENGINE
VALVE
using a valve refacer. Valve should make a uniform contact
with the seat at the center of valve face.
(2) If the margin is smaller than the service limit, replace the
valve.
Standard value:
Intake
Exhaust
Limit:
Intake
Exhaust
VALVE SPRING
(1) Measure the free height of the spring and, if it is smaller
than the limit, replace.
Standard value: 49.2 mm (1.937 in.)
Limit: 48.2 mm (1.898 in.)
(2) Measure the squareness of the spring and, if the limit is
exceeded, replace.
Standard value: 2" or less
1 EN0264
Limit: 4"
VALVE GUIDE
(1) Measure the clearance between the valve guide and valve
stem. If the limit is exceeded, replace the valve guide or
valve, or both.
Standard value:
Intake
Exhaust
Limit:
Intake
Exhaust
VALVE SEAT RECONDITIONING PROCEDURE
(1) Before correcting the valve seat, check for clearance
between the valve guide and valve and, if necessary,
replace the valve guide.
(2) Using the special tool or seat grinder, correct to obtain the
specified seat width and angle.
(3) After correction, valve and valve seat should be lapped with
a lapping compound.
1 EN0265
TSB Revision
1.2 mm (047 in.)
1.5 mm (.059 in.)
0.7 mm (028 in.)
1.0 mm (039 in.)
0.03 - 0.06 mm (0012 - .0024 in.)
0.05 - 0.09 mm (.0020 - .0035 in.)
0.10 mm (0039 in.)
0.15 mm (.0059 in.)