Subaru Impreza 2002 Service Manual page 224

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 — 92.015 mm (3.6222 — 3.6226 in)
B: 91.995 — 92.005 mm (3.6218 — 3.6222 in)
(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
CYLINDER BLOCK
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
Out-of-roundness:
Standard
Limit
H2M1732C
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(STi)-85
0.015 mm (0.0006 in)
0.050 mm (0.0020 in)
0.010 mm (0.0004 in)
0.050 mm (0.0020 in)
(A) Piston pin direction
(B) Thrust direction
MECHANICAL
S2M1821A