Subaru Legacy IV (2008 year). Manual - part 277

ME(H4DOTC)-88

Cylinder Block

MECHANICAL

D: ASSEMBLY

1) Apply oil to the surface of the connecting rod
bearings, and install the connecting rod bearings
on connecting rods and connecting rod caps.
2) Position each connecting rod with a side mark
facing forward, and install it.
3) Attach the connecting rod cap, and tighten with
the connecting rod bolt. Make sure the arrow mark
on connecting rod cap facing front during installa-
tion.

NOTE:
• Each connecting rod has its own mating cap.
Make sure that they are assembled correctly by
checking their matching number.
• When tightening the connecting rod nuts, apply
oil on the threads.

Tightening torque:

52 N·m (5.3 kgf-m, 38.4 ft-lb)

4) Install the oil ring upper rail, expander and lower
rail by hand.
5) Install the second ring and top ring using piston
ring expander.

NOTE:
Assemble so that the piston ring mark “R” faces the
top side of the piston.

(1)

Connecting rod bearing

(5)

Second ring

Tightening torque:N·m (kgf-m, ft-lb)

(2)

Connecting rod

(6)

Top ring

T: 52 (5.3, 38.4)

(3)

Connecting rod cap

(7)

Snap ring

(4)

Oil ring

(8)

Side mark

ME-02985

(1)

(7)

(4)

(5)

(6)

(3)

(2)

(8)

ME(H4DOTC)-89

Cylinder Block

MECHANICAL

E: INSPECTION

1. CYLINDER BLOCK

1) Check for cracks or damage. Use liquid pene-
trant tester on the important sections to check for
fissures. Check that there are no marks of gas leak-
ing or water leaking on gasket installing surface.
2) Check the oil passages for clogging.
3) Inspect the cylinder block surface that mates
with cylinder head for warping by using a straight
edge, and correct by grinding if necessary.

Warping limit:

0.025 mm (0.00098 in)

Grinding limit:

0.1 mm (0.004 in)

Standard height of cylinder block:

201.0 mm (7.91 in)

2. CYLINDER AND PISTON

1) The cylinder bore size is stamped on the front
upper face of the cylinder block.

NOTE:
• Measurement should be performed at a temper-
ature of 20°C (68°F).
• Standard sized pistons are classified into two
grades, “A” and “B”. These grades should be used
as guide lines in selecting a standard piston.

Standard diameter:

A: 99.505 — 99.515 mm (3.9175 — 3.9179 in)
B: 99.495 — 99.505 mm (3.9171 — 3.9175 in)

(A) Main journal size mark

(B) Cylinder block (RH) – (LH) combination mark

(D) #2 cylinder bore size mark

(E) #3 cylinder bore size mark

(F) #4 cylinder bore size mark

ME-00170

(A)

(B)

(F)

(D)

(C)

(E)

ME(H4DOTC)-90

Cylinder Block

MECHANICAL

2) Measure inner diameter of each cylinder.
Measure the inner diameter of each cylinder in both
the thrust and piston pin directions at the heights as
shown in the figure, using a cylinder bore gauge.

NOTE:
Measurement should be performed at a tempera-
ture of 20°C (68°F).

Taper:

Standard

0.015 mm (0.0006 in)

Out-of-roundness:

Standard

0.010 mm (0.0004 in)

3) When the piston is to be replaced due to general
or cylinder wear, select a suitable sized piston by
measuring the piston clearance.

4) Measure outer diameter of each cylinder.
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 (1.50 in)

Piston outer diameter:
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 out of
standard or if there is any damage on the cylinder
wall, rebore it to replace with an oversize piston.

CAUTION:
When any of the cylinders needs reboring, all
other cylinders must be bored at the same time,
and replaced with oversize pistons.

(2) If the cylinder inner diameter exceeds the limit
after boring and honing, replace the cylinder block.

NOTE:
Immediately after reboring, the cylinder diameter
may differ from its real diameter due to temperature
rise. Thus, when measuring the cylinder diameter,
wait until it has cooled to room temperature.

Cylinder inner diameter boring limit (diameter):

100.005 mm (3.9372 in)

(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)

ME-00171

(A)

(B)

ME-00172

ME(H4DOTC)-91

Cylinder Block

MECHANICAL

3. PISTON AND PISTON PIN

1) Check the piston and piston pin for breaks,
cracks or wear. Replace if faulty.
2) Check the piston ring groove for wear and dam-
age. Replace if faulty.
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.

Standard clearance between piston pin and
hole in piston:

Standard

0.004 — 0.008 mm (0.0002 — 0.0003 in)

4) Check the snap ring installation groove (A) on
the piston for burr. If necessary, remove burr from
the groove so that the piston pin can lightly move.

5) Check the piston pin snap ring for distortion,
cracks and wear.

4. PISTON RING

1) If the piston ring is broken, damaged or worn, or
if its tension is insufficient, or when the piston is re-
placed, replace the piston ring with a new part of
the same size as piston.

NOTE:
• The top ring and second ring have the mark to
determine the direction for installing. When install-
ing the ring to piston, face this mark to the top side.
• Oil ring consists of the upper rail, expander and
lower rail. When installing oil ring on piston, be
careful of the direction of each rail.

ME-00173

ME-00174

ME-00175

(A)

(A) Upper rail

(B) Expander

ME-02480

(A)

(B)

(C)

(A)

(B)

(C)

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