compression ratio SUBARU FORESTER 2004 Service User Guide

MECHANICAL
ME(H4DOTC)
Page
1. General Description ....................................................................................2
2. Compression .............................................................................................31
3. Idle Speed .................................................................................................32
4. Ignition Timing ...........................................................................................33
5. Intake Manifold Vacuum............................................................................34
6. Engine Oil Pressure ..................................................................................35
7. Fuel Pressure ............................................................................................36
8. Valve Clearance ........................................................................................37
9. Engine Assembly ......................................................................................41
10. Engine Mounting .......................................................................................50
11. Preparation for Overhaul ...........................................................................51
12. V-belt .........................................................................................................52
13. Crank Pulley ..............................................................................................55
14. Timing Belt Cover......................................................................................57
15. Timing Belt Assembly................................................................................58
16. Cam Sprocket ...........................................................................................67
17. Crank Sprocket .........................................................................................68
18. Camshaft ...................................................................................................69
19. Cylinder Head Assembly ...........................................................................76
20. Cylinder Block ...........................................................................................84
21. Intake and Exhaust Valve .......................................................................115
22. Piston ......................................................................................................116
23. Connecting Rod ......................................................................................117
24. Crankshaft ...............................................................................................118
25. Engine Trouble in General ......................................................................119
26. Engine Noise ...........................................................................................124

ME(H4DOTC)-2
MECHANICAL
General Description
1. General Description
A: SPECIFICATION
1. 2.0 L MODEL
NOTE:
STD: Standard I.D.: Inner Diameter O.D.: Outer Diameter OS: Oversize US: Undersize
EngineTy p eHorizontally opposed, liquid cooled, 4-cylinder, 4-stroke
gasoline engine
Valve arrangement Belt driven, double overhead camshaft, 4-valve/cylinder
Bore×Stroke mm (in) 92×75 (3.62×2.95)
Piston displacement
cm
3 (cu in)1,994 (121.67)
Compression ratio 8.0
Compression pres-
sure (at 200 — 300
rpm)kPa (kgf/cm
2, psi)981 — 1,177 (10 — 12, 142 — 171)
Number of piston rings Pressure ring: 2, Oil ring: 1
Intake valve timingOpeningMax. retard BTDC 3°
Min. advance BTDC 33°
ClosingMax. retard ABDC 33°
Min. advance ABDC 3°
Exhaust valve timingOpening BBDC 33°
Closing ATDC 3°
Valve clearanceIntake mm (in) 0.20±0.02 (0.0079±0.0008)
Exhaust mm (in) 0.35±0.02 (0.0138±0.0008)
Idling speed
[At neutral position on MT, or “P” or
“N” range on AT]
rpmNo loadMT: 700±100
AT : 7 0 0±100
A/C ONA/C Refrigerant pressure
(LOW)MT: 725±100
AT : 7 5 0±100
A/C Refrigerant pressure
(HIGH)MT: 800±100
AT : 8 2 5±100
Firing order 1 → 3 → 2 → 4
Ignition timing BTDC/rpm 12°±10°/700
Belt ten-
sion
adjusterProtrusion of adjuster rod 5.7 — 6.7 mm (0.224 — 0.264 in)
Belt ten-
sionerSpacer O.D. 17.955 — 17.975 mm (0.7069 — 0.7077 in)
Tensioner bush I.D. 18.0 — 18.08 mm (0.7087 — 0.7118 in)
Clearance between spacer and bushSTD 0.025 — 0.125 mm (0.0010 — 0.0049 in)
Limit 0.175 mm (0.0069 in)
Side clearance of spacerSTD 0.2 — 0.55 mm (0.0079 — 0.0217 in)
Limit 0.81 mm (0.0319 in)

ME(H4DOTC)-6
MECHANICAL
General Description
2. 2.5 L MODEL
NOTE:
STD: Standard I.D.: Inner Diameter O.D.: Outer Diameter OS: Oversize US: Undersize
EngineModel2.5 L
Ty p eHorizontally opposed, liquid cooled, 4-cylinder,
4-stroke gasoline engine
Valve arrangement Belt driven, double overhead camshaft, 4-valve/cylinder
Bore×Stroke mm (in) 99.5×79.0 (3.92×3.11)
Piston displacement
cm
3 (cu in)2,457 (149.94)
Compression ratio 8.2
Compression pres-
sure (at 200 — 300
rpm)kPa (kgf/cm
2, psi)981 — 1,177 (10 — 12, 142 — 171)
Number of piston rings Pressure ring: 2, Oil ring: 1
Intake valve timingOpeningMax. retard ATDC 5°
Min. advance BTDC 15°
ClosingMax. retard ABDC 65°
Min. advance ABDC 45°
Exhaust valve timingOpening BBDC 55°
Closing ATDC 5°
Valve clearanceIntake mm (in) 0.20±0.02 (0.0079±0.0008)
Exhaust mm (in) 0.35±0.02 (0.0138±0.0008)
Idling speed
[At neutral position on MT, or “P” or “N”
range on AT]
rpmNo loadMT: 700±100
AT : 7 0 0±100
A/C ONA/C Refrigerant pressure
(LOW)MT: 725±100
AT : 7 5 0±100
A/C Refrigerant pressure
(HIGH)MT: 800±100
AT : 8 2 5±100
Firing order 1 → 3 → 2 → 4
Ignition timing BTDC/rpmMT model 17°±10°/700
AT model 17°±10°/700

ME(H4DOTC)-30
MECHANICAL
General Description
2. GENERAL TOOL
E: PROCEDURE
It is possible to conduct the following service proce-
dures with engine on the vehicle, however, the pro-
cedures described in this section are based on the
condition that the engine is removed from the vehi-
cle.
V-belt
 Timing Belt
 Camshaft
 Cylinder Head
498277200 STOPPER SET Used for installing automatic transmission
assembly to engine.
24082AA230
(Newly adopted tool)CARTRIDGE Troubleshooting for electrical systems.
22771AA030 SUBARU SELECT
MONITOR KITTroubleshooting for electrical systems.
 English: 22771AA030 (Without printer)
 German: 22771AA070 (Without printer)
 French: 22771AA080 (Without printer)
 Spanish: 22771AA090 (Without printer)
TOOL NAME REMARKS
Compression gauge Used for measuring compression.ILLUSTRATION TOOL NUMBER DESCRIPTION REMARKS
ST-498277200
ST24082AA230
ST22771AA030

ME(H4DOTC)-31
MECHANICAL
Compression
2. Compression
A: INSPECTION
CAUTION:
After warming-up, engine becomes very hot. Be
careful not to burn yourself during measure-
ment.
1) After warming-up the engine, turn the ignition
switch to OFF.
2) Make sure that the battery is fully charged.
3) Release the fuel pressure. FU(H4DOTC)-54, RELEASING OF FUEL PRES-
SURE, OPERATION, Fuel.>
4) Remove all the spark plugs. IG(H4DOTC)-5, REMOVAL, Spark Plug.>
5) Fully open the throttle valve.
6) Check the starter motor for satisfactory perfor-
mance and operation.
7) Hold the compression gauge tight against spark
plug hole.
NOTE:
When using a screw-in type compression gauge,
the screw (put into cylinder head spark plug hole)
should be less than 18 mm (0.71 in) long.
8) Crank the engine by means of starter motor, and
then read the maximum value on the gauge when
the pointer is steady.9) Perform at least two measurements per cylinder,
and make sure that the values are correct.
Compression (350 rpm and fully open throttle):
Standard
981 — 1,177 kPa (10 — 12 kgf/cm
2, 142 —
171 psi)
Limit
882 kPa (9.0 kgf/cm
2, 128 psi)
Difference between cylinders
Less than 49 kPa (0.5 kgf/cm
2, 7 psi)
ME-00007

MECHANICAL
ME(H4DOTC)
Page
1. General Description ....................................................................................2
2. Compression .............................................................................................31
3. Idle Speed .................................................................................................32
4. Ignition Timing ...........................................................................................33
5. Intake Manifold Vacuum............................................................................34
6. Engine Oil Pressure ..................................................................................35
7. Fuel Pressure ............................................................................................36
8. Valve Clearance ........................................................................................37
9. Engine Assembly ......................................................................................41
10. Engine Mounting .......................................................................................50
11. Preparation for Overhaul ...........................................................................51
12. V-belt .........................................................................................................52
13. Crank Pulley ..............................................................................................55
14. Timing Belt Cover......................................................................................57
15. Timing Belt Assembly................................................................................58
16. Cam Sprocket ...........................................................................................67
17. Crank Sprocket .........................................................................................68
18. Camshaft ...................................................................................................69
19. Cylinder Head Assembly ...........................................................................76
20. Cylinder Block ...........................................................................................84
21. Intake and Exhaust Valve .......................................................................115
22. Piston ......................................................................................................116
23. Connecting Rod ......................................................................................117
24. Crankshaft ...............................................................................................118
25. Engine Trouble in General ......................................................................119
26. Engine Noise ...........................................................................................124

MECHANICAL
ME(H4DOTC)
Page
1. General Description ....................................................................................2
2. Compression .............................................................................................31
3. Idle Speed .................................................................................................32
4. Ignition Timing ...........................................................................................33
5. Intake Manifold Vacuum............................................................................34
6. Engine Oil Pressure ..................................................................................35
7. Fuel Pressure ............................................................................................36
8. Valve Clearance ........................................................................................37
9. Engine Assembly ......................................................................................41
10. Engine Mounting .......................................................................................50
11. Preparation for Overhaul ...........................................................................51
12. V-belt .........................................................................................................52
13. Crank Pulley ..............................................................................................55
14. Timing Belt Cover......................................................................................57
15. Timing Belt Assembly................................................................................58
16. Cam Sprocket ...........................................................................................67
17. Crank Sprocket .........................................................................................68
18. Camshaft ...................................................................................................69
19. Cylinder Head Assembly ...........................................................................76
20. Cylinder Block ...........................................................................................84
21. Intake and Exhaust Valve .......................................................................115
22. Piston ......................................................................................................116
23. Connecting Rod ......................................................................................117
24. Crankshaft ...............................................................................................118
25. Engine Trouble in General ......................................................................119
26. Engine Noise ...........................................................................................124

ME(H4DOTC)-118
MECHANICAL
Engine Trouble in General
25.Engine Trouble in General
A: INSPECTION
NOTE:
“RANK” shown in the chart refers to the possibility of reason for the trouble in order (“Very often” to “Rarely”)
A — Very often
B — Sometimes
C — Rarely
TROUBLE PROBLEM PARTS, ETC. POSSIBLE CAUSE RANK
1. Engine will not start.
1) Starter does not turn. Starter Defective battery-to-starter harness B
Defective starter switch C
Defective inhibitor switch or neutral switch C
Defective starter B
Battery Poor terminal connection A
Run-down battery A
Defective charging system B
Friction Seizure of crankshaft and connecting rod bearing C
Seized camshaft C
Seized or stuck piston and cylinder C
2) Initial combustion does
not occur. Starter Defective starter C
Engine control system A
Fuel line Defective fuel pump and relay A
Lack of or insufficient fuel B
Belt Defective (deterioration, etc.) B
Defective timing B
Compression Incorrect valve clearance C
Loosened spark plugs or defective gasket C
Loosened cylinder head bolts or defective gasket C
Improper valve seating C
Defective valve stem C
Worn or broken valve spring B
Worn or stuck piston rings, cylinder and piston C
Incorrect valve timing B
Improper engine oil (low viscosity) B
3) Initial combustion occurs. Engine control system A
Intake system Defective intake manifold gasket B
Defective throttle body gasket B
Fuel line Defective fuel pump and relay C
Clogged fuel line C
Lack of or insufficient fuel B
Belt Defective (deterioration, etc.) B
Defective timing B
Compression Incorrect valve clearance C
Loosened spark plugs or defective gasket C
Loosened cylinder head bolts or defective gasket C
Improper valve seating C
Defective valve stem C
Worn or broken valve spring B
Worn or stuck piston rings, cylinder and piston C
Incorrect valve timing B
Improper engine oil (low viscosity) B

ME(H4DOTC)-119
MECHANICAL
Engine Trouble in General
4) Engine stalls after initial
combustion. Engine control system A
Intake system Loosened or cracked intake duct B
Loosened or cracked PCV hose C
Loosened or cracked vacuum hose C
Defective intake manifold gasket B
Defective throttle body gasket B
Dirty air cleaner element C
Fuel line Clogged fuel line C
Lack of or insufficient fuel B
Belt Defective (deterioration, etc.) B
Defective timing B
Compression Incorrect valve clearance C
Loosened spark plugs or defective gasket C
Loosened cylinder head bolts or defective gasket C
Improper valve seating C
Defective valve stem C
Worn or broken valve spring B
Worn or stuck piston rings, cylinder and piston C
Incorrect valve timing B
Improper engine oil (low viscosity) B
2. Rough idle and engine
stallEngine control system A
Intake system Loosened or cracked intake duct A
Loosened or cracked PCV hose A
Loosened or cracked vacuum hose A
Defective intake manifold gasket B
Defective throttle body gasket B
Defective PCV valve C
Loosened oil filler cap B
Dirty air cleaner element C
Fuel line Defective fuel pump and relay C
Clogged fuel line C
Lack of or insufficient fuel B
Belt Defective timing C
Compression Incorrect valve clearance B
Loosened spark plugs or defective gasket B
Loosened cylinder head bolts or defective gasket B
Improper valve seating B
Defective valve stem C
Worn or broken valve spring B
Worn or stuck piston rings, cylinder and piston B
Incorrect valve timing A
Improper engine oil (low viscosity) B
Lubrication system Incorrect oil pressure B
Defective rocker cover gasket C
Cooling system Overheating C
Others Malfunction of evaporative emission control system A
Stuck or damaged throttle valve B
Accelerator cable out of adjustment C TROUBLE PROBLEM PARTS, ETC. POSSIBLE CAUSE RANK

ME(H4DOTC)-120
MECHANICAL
Engine Trouble in General
3. Low output, hesitation and
poor accelerationEngine control system A
Intake system Loosened or cracked intake duct A
Loosened or cracked PCV hose A
Loosened or cracked vacuum hose B
Defective intake manifold gasket B
Defective throttle body gasket B
Defective PCV valve B
Loosened oil filler cap B
Dirty air cleaner element A
Fuel line Defective fuel pump and relay B
Clogged fuel line B
Lack of or insufficient fuel C
Belt Defective timing B
Compression Incorrect valve clearance B
Loosened spark plugs or defective gasket B
Loosened cylinder head bolts or defective gasket B
Improper valve seating B
Defective valve stem C
Worn or broken valve spring B
Worn or stuck piston rings, cylinder and piston C
Incorrect valve timing A
Improper engine oil (low viscosity) B
Lubrication system Incorrect oil pressure B
Cooling system Overheating C
Over cooling C
Others Malfunction of evaporative emission control system A
4. Surging Engine control system A
Intake system Loosened or cracked intake duct A
Loosened or cracked PCV hose A
Loosened or cracked vacuum hose A
Defective intake manifold gasket B
Defective throttle body gasket B
Defective PCV valve B
Loosened oil filler cap B
Dirty air cleaner element B
Fuel line Defective fuel pump and relay B
Clogged fuel line B
Lack of or insufficient fuel C
Belt Defective timing B
Compression Incorrect valve clearance B
Loosened spark plugs or defective gasket C
Loosened cylinder head bolts or defective gasket C
Improper valve seating C
Defective valve stem C
Worn or broken valve spring C
Worn or stuck piston rings, cylinder and piston C
Incorrect valve timing A
Improper engine oil (low viscosity) B
Cooling system Overheating B
Others Malfunction of evaporative emission control system C TROUBLE PROBLEM PARTS, ETC. POSSIBLE CAUSE RANK