Subaru 2006 Legacy, Manual

Page: 852 / 4302

ME(H4SO)-7 8
Cylinder Block
MECHANICAL
4) How to measure the outer diameter of each cyl-
inder:
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:
38.2 mm (1.504 in)
Standard:
A: 99.505 — 99.515 mm (3.9175 — 3.9179 in)
B: 99.495 — 99.505 mm (3.9171 — 3.9175 in)
0.25 mm (0.0098 in) oversize:
99.745 — 99.765 mm (3.9270 — 3.9278 in)
0.50 mm (0.0197 in) oversize:
99.995 — 100.015 mm (3.9368 — 3.9376 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°C (68°F):
Standard:
–0.010 — 0.010 mm (–0.00039 — 0.00039 in)
6) Boring and honing
(1) If any of the measured value of taper, out-of-
roundness or cylinder-to-piston clearance is not
standard or if there is any damage on the cylin-
der 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 the
limit after boring and honing, replace the cylin-
der block.
Limit of cylinder inner diameter:
100.005 mm (3.9372 in)
NOTE:
Immediately after reboring, the cylinder diameter
may differ from its real diameter due to temperature
rise. Thus, pay attention when measuring the cylin-
der 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 faulty.
2) Measure the piston-to-cylinder clearance at
each cylinder. <Ref. to ME(H4SO)-77, CYLINDER
AND PISTON, INSPECTION, Cylinder Block.> If
any of the clearances is not within the standard val-
ue, replace the piston and bore the cylinder to en-
able use of an oversized piston.
3) Make sure that the piston pin can be inserted
into the piston pin hole with a thumb at 20°C (68°F).
Replace if faulty.
Clearance between piston hole and piston pin:
Standard:
0.004 — 0.008 mm (0.0002 — 0.0003 in)
ME-00172
H
ME-00173
ME-00174
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