Subaru Legacy IV (2008 year). Manual — part 255

IN(H4DOTC)-17

Air By-pass Valve

INTAKE (INDUCTION)

9. Air By-pass Valve

A: REMOVAL

1) Remove the collector cover.
2) Disconnect the air by-pass pipe (A) and vacuum
hose (B) from the air by-pass valve (C).
3) Remove the air by-pass valve (C) from the inter-
cooler.

B: INSTALLATION

Install in the reverse order of removal.

NOTE:
• Use new O-rings.
• Be careful not to pinch the O-ring.

Tightening torque:

6.5 N·m (0.7 kgf-m, 4.8 ft-lb)

(A) Air by-pass pipe

(B) Vacuum hose

(C) Air by-pass valve

(A)

(B)

(C)

IN-02477

(A)

(B)

(C)

IN-02477

IN(H4DOTC)-18

Air By-pass Valve

INTAKE (INDUCTION)

ME(H4DOTC)-2

General Description

MECHANICAL

1. General Description

A: SPECIFICATION

Engine

Model

2.5 L

Cylinder arrangement

Horizontally opposed, liquid cooled, 4-cylinder,

4-stroke gasoline engine

Valve system mechanism

Belt driven, double overhead camshaft,

4-valve/cylinder

Bore × Stroke

mm (in)

99.5 × 79.0 (3.92 × 3.11)

Displacement

cm

3

(cu in)

2,457 (149.94)

Compression ratio

8.4

Compression pressure
(at 200 — 300 rpm)

kPa (kg/cm

2

, psi)

981 — 1,177 (10 — 12, 142 — 171)

Number of piston rings

Pressure ring: 2, Oil ring: 1

Intake valve timing

Open

Max. retard

ATDC 5°

Min. advance

BTDC 35°

Close

Max. retard

ABDC 65°

Min. advance

ABDC 25°

Exhaust valve timing

Open

BBDC 55°

Close

ATDC 5°

Valve clearance

mm (in)

Intake

0.20

r0.02 (0.0079r0.0008)

Exhaust

0.35

r0.02 (0.0138r0.0008)

Idling speed [at neutral position on MT,
or “P” or “N” position on AT]

rpm

No load

750

r100

A/C ON

800

r100 (MT model)

825

r100 (AT model)

Ignition order

1

o 3 o 2 o 4

Ignition timing

BTDC/rpm

MT model

12°

r10°/750

AT model

17°

r10°/750

ME(H4DOTC)-3

General Description

MECHANICAL

NOTE:
OS: Oversize

US: Undersize

Belt tension
adjuster

Protrusion of adjuster rod

mm (in)

5.2 — 6.2 (0.205 — 0.244)

Camshaft

Bending limit

mm (in)

0.020 (0.00079) or less

Thrust clearance

mm (in) Standard

0.068 — 0.116 (0.0027 — 0.0047)

Cam lobe height

mm (in)

Intake

Standard

46.55 — 46.65 (1.833 — 1.837)

Exhaust

Standard

46.75 — 46.85 (1.841 — 1.844)

Journal O.D.

mm (in) Standard

Front

37.946 — 37.963 (1.4939 — 1.4946)

Center, rear

29.946 — 29.963 (1.1790 — 1.1796)

Journal clearance

mm (in) Standard

0.037 — 0.072 (0.0015 — 0.0028)

Cylinder
head

Surface warping limit
(Mating surface with cylinder block)

mm (in)

0.035 (0.0014)

Grinding limit

mm (in)

0.3 (0.012)

Standard height

mm (in)

127.5 (5.02)

Valve seat

Seating angle

90°

Contacting width

mm (in)

Intake

Standard

0.6 — 1.4 (0.024 — 0.055)

Exhaust

Standard

1.2 — 1.8 (0.047 — 0.071)

Valve guide

Inside diameter

mm (in)

6.000 — 6.012 (0.2362 — 0.2367)

Protrusion above head

mm (in)

15.8 — 16.2 (0.622 — 0.638)

Valve

Head edge thickness

mm (in)

Intake

Standard

1.0 — 1.4 (0.039 — 0.055)

Exhaust

Standard

1.3 — 1.7 (0.051 — 0.067)

Stem outer diameter

mm (in)

Intake

5.955 — 5.970 (0.2344 — 0.2350)

Exhaust

5.945 — 5.960 (0.2341 — 0.2346)

Valve stem gap

mm (in) Standard

Intake

0.030 — 0.057 (0.0012 — 0.0022)

Exhaust

0.040 — 0.067 (0.0016 — 0.0026)

Overall length

mm (in)

Intake

104.4 (4.110)

Exhaust

104.65 (4.1201)

Valve spring

Free length

mm (in)

47.32 (1.863)

Squareness

2.5°, 2.1 mm (0.083 in) or less

Tension/spring height

N (kgf, lb)/mm (in)

Set

205 — 235

(20.9 — 24.0, 46.1 — 52.8)/36.0 (1.417)

Lift

426 — 490

(43.4 — 50.0, 95.8 — 110)/26.5 (1.043)

Valve lifter

Outer diameter

mm (in) Standard

34.959 — 34.975 (1.3763 — 1.3770)

Inner diameter (cylinder head)

mm (in) Standard

34.994 — 35.016 (1.3777 — 1.3786)

Valve lifter clearance

mm (in) Standard

0.019 — 0.057 (0.0007 — 0.0022)

Cylinder
block

Surface warping limit
(Mating surface with cylinder head)

mm (in)

0.025 (0.0098)

Grinding limit

mm (in)

0.1 (0.004)

Standard height

mm (in)

201.0 (7.91)

Cylinder inner diameter

mm (in) Standard

A

99.505 — 99.515 (3.9175 — 3.9179)

B

99.495 — 99.505 (3.9171 — 3.9175)

Taper

mm (in) Standard

0.015 (0.0006)

Out-of-roundness

mm (in) Standard

0.010 (0.0004)

Piston clearance

mm (in) Standard

–0.010 — 0.010 (–0.00039 — 0.00039)

Cylinder inner diameter boring limit (diameter)

mm (in)

To 100.005 (3.9372)

Piston

Outer diameter

mm (in)

Standard

A

99.505 — 99.515 (3.9175 — 3.9179)

B

99.495 — 99.505 (3.9171 — 3.9175)

0.25 (0.0098) OS

99.745 — 99.765 (3.9270 — 3.9278)

0.50 (0.0197) OS

99.995 — 100.015 (3.9368 — 3.9376)