Subaru Legacy III (2000-2003 year). Manual - part 430

ME(H4DOSTC)-84

MECHANICAL

CYLINDER BLOCK

Standard diameter:

A: 92.005 — 92.015 mm (3.6222 — 3.6226
in)
B: 91.995 — 92.005 mm (3.6218 — 3.6222
in)

2) How to measure the inner diameter of each cyl-
inder:
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.

NOTE:
Measurement should be performed at a tempera-
ture of 20

C (68

F).

Taper:

Standard

0.015 mm (0.0006 in)

Limit

0.050 mm (0.0020 in)

Out-of-roundness:

Standard

0.010 mm (0.0004 in)

Limit

0.050 mm (0.0020 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 shown in the figure. (Thrust direction)

NOTE:
Measurement should be performed at a tempera-
ture of 20

C (68

F).

(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

( B )

( C )

( D )

( E )

( F )

( 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)

ME-00171

( A )

( B )

ME(H4DOSTC)-85

MECHANICAL

CYLINDER BLOCK

Piston grade point H:

38.7 mm (1.524 in)

Piston outer diameter:

Standard

A: 91.985 — 91.995 mm (3.6214 — 3.6218
in)
B: 91.975 — 91.985 mm (3.6211 — 3.6214
in)

0.25 mm (0.0098 in) oversize

92.225 — 92.235 mm (3.6309 — 3.6313 in)

0.50 mm (0.0197 in) oversize

92.475 — 92.485 mm (3.6407 — 3.6411 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 — 0.030 mm (0.0004 — 0.0012 in)

Limit

0.050 mm (0.0020 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.

NOTE:
When any of the cylinders needs reboring, all other
cylinders must be bored at the same time, and use
oversize pistons. Do not perform boring on one cyl-
inder only, nor use an oversize piston for one cylin-
der only.

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

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.

Limit of cylinder enlarging (boring):

0.5 mm (0.020 in)

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.
2) Measure the piston-to-cylinder clearance at
each cylinder. <Ref. to ME(H4DOSTC)-83, CYLIN-
DER AND PISTON, INSPECTION, Cylinder
Block.> If any of the clearances is not within speci-
fication, replace the piston or bore the cylinder to
use an oversize 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 defective.

Standard clearance between piston pin and
hole in piston:

Standard

0.004 — 0.008 mm (0.0002 — 0.0003 in)

Limit

0.020 mm (0.0008 in)

ME-00172

ME-00173

ME-00174

ME(H4DOSTC)-86

MECHANICAL

CYLINDER BLOCK

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

5) Check the piston pin circlip 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 one of
the same size as the piston.

NOTE:
• Marks are shown on the end of top and second
rings. When installing the rings to piston, face this
mark upward.
• Oil ring consists of upper rail, expander and low-
er rail. When installing on piston, be careful of each
rail's direction.

2) Clean up the piston ring groove and piston ring.
3) Squarely place the piston ring and oil ring in cyl-
inder, and then measure the piston ring gap with a
thickness gauge.

4) Measure the clearance between piston ring and
piston ring groove with a thickness gauge.

NOTE:
Before measuring the clearance, clean the piston
ring groove and piston ring.

(A) Upper rail

(B) Expander

ME-00175

( A )

ME-00375

(A)

(B)

(C)

(A)

(B)

(C)

Unit: mm (in)

Standard

Limit

Piston
ring gap

Top ring

0.20 — 0.25

(0.0079 — 0.0098)

1.0 (0.039)

Second
ring

0.35 — 0.50

(0.0138 — 0.0197)

1.0 (0.039)

Oil ring
rail

0.20 — 0.50

(0.0079 — 0.0197)

1.5 (0.059)

Unit: mm (in)

Standard

Limit

Clearance
between pis-
ton ring and
piston ring
groove

Top ring

0.055 — 0.090

(0.0022 —

0.0035)

0.15 (0.0059)

Second
ring

0.030 — 0.070

(0.0012 —

0.0028)

0.15 (0.0059)

ME-00177

ME-00178

ME(H4DOSTC)-87

MECHANICAL

CYLINDER BLOCK

5. CONNECTING ROD

1) Replace the connecting rod, if the large or small
end thrust surface is damaged.
2) Check for bend or twist using a connecting rod
aligner. Replace the connecting rod if the bend or
twist exceeds the limit.

Limit of bend or twist per 100 mm (3.94 in) in
length:

0.10 mm (0.0039 in)

3) Install the connecting rod fitted with bearing to
crankshaft, and then measure the side clearance
(thrust clearance). Replace the connecting rod if
the side clearance exceeds the specified limit.

Connecting rod side clearance:

Standard

0.070 — 0.330 mm (0.0028 — 0.0130 in)

Limit

0.4 mm (0.016 in)

4) Inspect the connecting rod bearing for scar,
peeling, seizure, melting, wear, etc.
5) Measure the oil clearance on individual connect-
ing rod bearings by means of plastigauge. If any oil
clearance is not within specification, replace the
defective bearing with a new one of standard size
or undersize as necessary. (See the table below.)

Connecting rod oil clearance:

Standard

0.020 — 0.046 mm (0.0008 — 0.0018 in)

Limit

0.05 mm (0.0020 in)

(A) Thickness gauge

(B) Connecting rod

( A )

( B )

( A )

( B )

ME-00179

ME-00180

Unit: mm (in)

Bearing

Bearing size

(Thickness at center)

Outer diameter of

crank pin

Standard

1.486 — 1.498

(0.0585 — 0.0590)

51.984 — 52.000

(2.0466 — 2.0472)

0.03

(0.0012)

undersize

1.504 — 1.512

(0.0592 — 0.0595)

51.954 — 51.970

(2.0454 — 2.0461)

0.05

(0.0020)

undersize

1.514 — 1.522

(0.0596 — 0.0599)

51.934 — 51.950

(2.0447 — 2.0453)

0.25

(0.0098)

undersize

1.614 — 1.622

(0.0635 — 0.0639)

51.734 — 51.750

(2.0368 — 2.0374)

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