Subaru 1600 Service Manual page 89

11. Cylinder and Piston
1) 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.
Cylinder head mating surface A
Stmm·"~m,
A: Thrust direction
B: Piston pin direction
A5·068
Q
1,600 cc
30mm (1.18 in)
1,800 cc 33.5 mm (1.319 in)
Fig. 3-97 Positions for cylinder bore
measurement
NOTE:
Measurement should be performed at
a temperature of 20
0
e
(B8°F).
Fig. 3-98 Measuring cylinier bore
ENGINE
2) Boring and honing
a. If the value of taper, out-of-round·
ness, 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 piston.
NOTE:
When any of the cylinders needs rebor·
ing, all other cylinders must be bored
at the same time, and use oversize
pistons. Do not perform boring on one
cylinder only, nor use an oversize
piston for one cylinder only.
b. Get four of the oversize pistons and
measure the outer diameter of each
piston at the height shown in the
figure. (Thrust direction)
26.3mm
\1.035
in)
A5-070
Fig. 3-99 Position for.measuring
piston diameter
Cylinder bore
Standard diameter (Both 1800 and 1600)
91.985 92.015 mm
(3.6214
3.6226 in)
Standard 0.01 5 mm (0.0006 in)
Taper
Limit
0.050 mm (0.0020 in)
Standard 0.010 mm (0.0004 in)
Out-of roundness
Limit
0.050 mm (0.0020 in)
I
I
Standard
0.010 - 0.040 mm
l
(0.0004 0.0016 in)
Cylinder to piston clearance
at 20°C (68°F)
0.060 mm
Limit
(0.0024 in)
3-52
A5-071
Fig. 3·100 Measuring piston diameter
Piston outer diameter
Standard
91.960 - 91.990 mm
(3.6205 - 3.6216 in)
0.25 mm
92.210- 92.240 mm
(0.0098 in)
(3.6303 - 3.6315 in)
oversize
0.50mm
92.460 - 92.490 mm
(0.0197 in)
(3.6402 - 3.64)3 in)
oversize
NOTE:
Measurement should be performed at
a temperature of 20
0
e
(G8°F).
c. If the cylinder inner diameter ex-
ceeds the following enlarging limit
after boring and honing, replace the
crankcase.
Enlarging limit
of cylinder 0.50 mm (0.0197 in)
inner diameter
NOTE:
Immediately after reboring, the cyl·
inder diameter may differ from its real
diameter due to temperature rise.
Thus, pay attention to this when
measuring the cylinder diameter.
d. Inspect the cylinder bore for taper,
out-of·roundness, and diameter dif·
ferences.
Diameter difference 0.050 mm
between cylinders (0.0020 in)
or
less
NOTE:
Measure the inner diameter of the
cylinder when the temperature is 20
0
e
{B8°F}.