Subaru Impreza 2002 Service Manual page 944

3) Measure the warping of the cylinder head sur-
face that mates with crankcase using a straight
edge and thickness gauge.
If the warping exceeds 0.05 mm (0.0020 in), re-
grind the surface with a surface grinder.
Warping limit:
0.05 mm (0.0020 in)
Grinding limit:
0.1 mm (0.004 in)
Standard height of cylinder head:
97.5 mm (3.839 in)
CAUTION:
Uneven torque for the cylinder head bolts can
cause warping. When reassembling, pay spe-
cial attention to the torque so as to tighten
evenly.
(A) Straight edge
(B) Thickness gauge
CYLINDER HEAD ASSEMBLY
S2M1817A
ME-67
2. VALVE SEAT
Inspect the intake and exhaust valve seats, and
then correct the contact surfaces with valve seat
cutter if they are defective or when valve guides are
replaced.
Valve seat width: W
Intake
Standard 1.0 mm (0.039 in)
Limit 1.7 mm (0.067 in)
Exhaust
Standard 1.4 mm (0.055 in)
Limit 2.1 mm (0.083 in)
MECHANICAL
G2M0149
B2M0074