Subaru Legacy 2004 Service Manual page 1191

MECHANICAL
Out-of-roundness:
Standard
0.010 mm (0.0004 in)
(A)
(A) Piston pin direction
(B) Thrust direction
H1: 10 mm (0.39 in)
H2: 45 mm (1.77 in)
H3: 80 mm (3.15 in)
H4: 115 mm (4.53 in)
3) When the piston is to be replaced due to general
or cylinder wear, determine a suitable sized piston
by measuring the piston clearance.
4) How to measure the outer diameter of each pis-
ton:
Measure the outer diameter of each piston at the
height as shown in the figure. (Thrust direction)
NOTE:
Measurement should be performed at a tempera-
ture of 20#C (68#F).
Piston grade point H:
40.0 mm (1.57 in)
Cylinder Block
(B)
H1
H2
H3
H4
ME-00171
ME(H4DOTC)-80
Piston outer diameter:
Standard
A: 92.005 — 92.015 mm (3.6222 — 3.6226
in)
B: 91.995 — 92.005 mm (3.6219 — 3.6222
in)
0.25 mm (0.0098 in) oversize
92.245 — 92.265 mm (3.6317 — 3.6467 in)
0.50 mm (0.0197 in) oversize
92.495 — 92.515 mm (3.6415 — 3.6423 in)
5) Calculate the clearance between cylinder and
piston.
NOTE:
Measurement should be performed at a tempera-
ture of 20#C (68#F).
Cylinder to piston clearance at 20
Standard
$
0.010 — 0.010 mm (
6) Boring and honing:
(1) If one of the values of taper, out-of-round-
ness, or cylinder-to-piston clearance exceeds
the specified limit or is out of standard, or if there
is any damage on the cylinder wall, rebore it to
use an oversize piston.
CAUTION:
When any of the cylinders needs reboring, all
other cylinders must be bored at the same time,
and use oversize pistons. Do not perform bor-
ing on one cylinder only. Nor use an oversize
piston for one cylinder only.
(2) If the cylinder inner diameter exceeds
92.515 mm (3.6423 in) after boring and honing,
replace the crankcase.
NOTE:
Immediately after reboring, the cylinder diameter
may differ from its real diameter due to temperature
rise. Thus, pay attention to this when measuring
the cylinder diameter.
3. PISTON AND PISTON PIN
1) Check the pistons and piston pins for damage,
cracks, and wear and the piston ring grooves for
wear and damage. Replace if defective.
H
ME-00172
# #
C (68 F):
$
0.00039 — 0.00039 in)