Subaru 2002 IMPREZA Service Manual page 190

CYLINDER BLOCK
MECHANICAL
2. CYLINDER AND PISTON
1) The cylinder bore size is stamped on the cylinder
block's front upper surface.
CAUTION:
Measurement should be performed at a temper-
ature of 20°C (68°F).
NOTE:
Standard sized pistons are classified into two
grades,
" A
and "B". These grades should be used
as a guide line in selecting a standard piston.
Standard diameter:
A: 92.005
-
92.01 5 mm (3.6222
-
3.6226
in)
B: 91.995
-
92.005 mm (3.6218
-
3.6222
in)
(E)
H2M1732C
(A) Main journal size mark
(B) Cylinder block RH-LH combination mark
(C) #1 cylinder bore size mark
(D) #2 cylinder bore size mark
(E)
#3 cylinder bore size mark
(F) #4 cylinder bore size mark
2) How to measure the inner diameter of each cyl-
inder:
Measure the inner diameter of each cylinder in both
the thrust and piston pin directions at the heights
shown in the figure, using a cylinder bore gauge.
CAUTION:
Measurement should be performed at a temper-
ature of 20°C (68°F).
Taper:
Standard
Limit
0.015 mm (0.0006 in)
0.050 mm (0.0020 in)
Out-o f-roundness:
Standard
Limit
0.010 mm (0.0004 in)
0.050 mm (0.0020 in)
F l O
(0.39)
45 (1.77)
80 (3.15)
115 (4.53)
W
S2M1821A
Unit:
mm (in)
(A) Piston pin direction
(B) Thrust direction
3) When the piston is to be replaced due to general
or cylinder wear, determine a suitable sized piston
by measuring the piston clearance.
ME(D0HC TURBO)-84