Subaru 2002 Impreza - Page 191

MECHANICAL
CYLINDER BLOCK
4) How to measure the outer diameter of each pis-
ton:
Measure the outer diameter of each piston at the
height shown in the figure. (Thrust direction)
CAUTION:
Measurement should be performed at a temper-
ature of 20°C
(68°F).
Piston grade point H:
37.0 mm (1.457 in)
Piston outer diameter:
Standard
A: 91.985 - 91.995 mm
(3.6214
- 3.6218 in)
B: 91.975 - 91.985 mm
(3.621 1
- 3.6214 in)
0.25 mm (0.0098 in) oversize
92.225-92.235"
(3.6309
- 3.6313 in)
0.50 mm (0.0197 in) oversize
92.475-92.485"
(3.6407
- 3.641 1 in)
6) Boring and honing:
(1) If the value of taper, out-of-roundness, or
cylinder-to-piston clearance measured exceeds
the specified limit or
if there is any damage on
the cylinder wall, rebore
it to use an oversize pis-
ton.
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 crank-
case.
CAUTION:
Immediately after reboring, the cylinder diame-
ter may differ from its real diameter due to tem-
perature rise. Thus, pay attention to this when
measuring the cylinder diameter.
Limit of cylinder enlarging (boring):
0.5 mm (0.020 in)
IJ B2M1305A
5) Calculate the clearance between cylinder and
piston.
CAUTION:
Measurement should be performed at a temper-
ature of
20°C (68°F).
Cylinder to piston clearance at 20°C (68OF):
0.010
- 0.030 mm (0.0004 - 0.0012 in)
0.050 mm (0.0020 in)
Standard
Limit
ME(D0HC TU RBO)-85