Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Service manual — part 171

ME(w/o STI)-65

Camshaft

MECHANICAL

11) Connect the PCV hose (A) and PCV hose as-

sembly (B) to the rocker cover.
NOTE:

Use a new clamp for the PCV hose (A), fit the cut

out in the ST with the protrusion on the clamp as

shown in the figure, and lock the clamp.

ST 18353AA000 CLAMP PLIERS

12) Connect the connector to oil flow control sole-

noid valve.

13) Install the ignition coil. <Ref. to IG(w/o STI)-8,

INSTALLATION, Ignition Coil.>

14) Install the air duct B (B) to the rocker cover LH

and the air duct A (A).
Tightening torque:

6.4 N·m (0.7 kgf-m, 4.7 ft-lb)

15) Securely install the engine harness with clip (A)

and stay (B) to the rocker cover RH.
Tightening torque:

6.4 N·m (0.7 kgf-m, 4.7 ft-lb)

ME-04374

ST

ME-05768

(A)

(B)

(A)

(B)

ME-05977

ME-04965

(B)

(A)

ME-04652

(A)

(B)

ME(w/o STI)-66

Camshaft

MECHANICAL

16) Install the timing belt cover. <Ref. to ME(w/o

STI)-47, INSTALLATION, Timing Belt Cover.>

17) Install the crank pulley. <Ref. to ME(w/o STI)-

45, INSTALLATION, Crank Pulley.>

18) Install the rear side belt. <Ref. to ME(w/o STI)-

39, REAR SIDE BELT, INSTALLATION, V-belt.>

19) Install the engine to the vehicle. <Ref. to ME(w/

o STI)-33, INSTALLATION, Engine Assembly.>

C: INSPECTION

1) Measure the bend, and repair or replace if nec-

essary.
Camshaft bend limit:

0.020 mm (0.00079 in)

2) Check the journal for damage and wear. Re-

place if faulty.

3) Check the cutout portion used for camshaft sen-

sor for damage. Replace if faulty.

4) Check the cam face condition, and remove the

minor faults by grinding with oil stone. If offset wear

occurs, replace it.

5) Measure the cam lobe height “H” and cam base

circle diameter “A”. If it exceeds the standard or off-

set wear occurs, replace it.
Cam lobe height H:
Standard

Intake

46.55 — 46.65 mm (1.833 — 1.837 in)

Exhaust

46.75 — 46.85 mm (1.841 — 1.844 in)

Cam base circle diameter A:

Standard

37.0 mm (1.457 in)

6) Measure the outside diameter of camshaft jour-

nal. If the journal diameter is not within specifica-

tion, check the oil clearance.

7) Measure the oil clearance of camshaft journal.

(1) Clean the camshaft cap and cylinder head

camshaft journal.

(2) Place the camshaft on cylinder head. (With-

out installing the valve lifter)

(3) Place a plastigauge across each camshaft

journals.

(4) Gradually tighten the camshaft cap in at

least two steps, in alphabetical order shown in

the figure, and then tighten to the specified

torque. Do not turn the camshaft.

Tightening torque:

T1: 9.75 N·m (1.0 kgf-m, 7.2 ft-lb)

T2: 20 N·m (2.0 kgf-m, 14.8 ft-lb)

(5) Remove the camshaft cap.

ME-00118

ME-00276

H

A

Camshaft journal

Front

Center, rear

Standard
mm (in)

37.946 — 37.963

(1.4939 — 1.4946)

29.946 — 29.963

(1.1790 — 1.1796)

ME-05980

(G)

(E)

(C)

(A)

(K)

(L)

(J)

(I)

(B)

(D)

(H)

(F)

(G)

(E)

(C)

(A)

(K)

(L)

(J)

(I)

(B)

(D)

(H)

(F)

T1

T2

T1

T2

T2

T2

T1

T1

ME(w/o STI)-67

Camshaft

MECHANICAL

(6) Measure the widest point of the plastigauge

on each journal. If oil clearance exceeds the

standard, replace the camshaft. If necessary,

replace the camshaft caps and cylinder head as

a set.

Camshaft oil clearance:

Standard

0.037 — 0.072 mm (0.0015 — 0.0028 in)

(7) Completely remove the plastigauge.

8) Measure the thrust clearance with setting the

dial gauge at end surface of camshaft. If the thrust

clearance is not within the standard or there is off-

set wear, replace the camshaft caps and cylinder

head as a set. If necessary replace the camshaft.
Camshaft thrust clearance:

Standard

0.068 — 0.116 mm (0.0027 — 0.0047 in)

ME-00119

ME-00121

ME(w/o STI)-68

Cylinder Head

MECHANICAL

19.Cylinder Head

A: REMOVAL

1) Remove the engine from the vehicle. <Ref. to

ME(w/o STI)-29, REMOVAL, Engine Assembly.>

2) Remove the rear side belt. <Ref. to ME(w/o STI)-

38, REAR SIDE BELT, REMOVAL, V-belt.>

3) Remove the intake manifold. <Ref. to FU(w/o

STI)-18, REMOVAL, Intake Manifold.>

4) Remove the crank pulley. <Ref. to ME(w/o STI)-

45, REMOVAL, Crank Pulley.>

5) Remove the timing belt cover. <Ref. to ME(w/o

STI)-47, REMOVAL, Timing Belt Cover.>

6) Remove the timing belt. <Ref. to ME(w/o STI)-

48, REMOVAL, Timing Belt.>

7) Remove the cam sprocket. <Ref. to ME(w/o

STI)-57, REMOVAL, Cam Sprocket.>

8) Remove the secondary air combination valve.

<Ref. to EC(w/o STI)-30, REMOVAL, Secondary

Air Combination Valve.>

9) Remove the bolts which secure A/C compressor

bracket to cylinder head.

10) Remove the oil pipe. <Ref. to LU(STI)-25, RE-

MOVAL, Oil Pipe.>

11) Remove the camshaft. <Ref. to ME(w/o STI)-

59, REMOVAL, Camshaft.>

12) Remove the oil level gauge guide. (LH side

only)

13) Remove the cylinder head bolts in alphabetical

order shown in the figure.
NOTE:

Leave the bolts (A) and (D) engaged by three or

four threads to prevent the cylinder head from fall-

ing.

14) While tapping the cylinder head with a plastic

hammer, separate it from cylinder block. Remove

the bolts (A) and (D) to remove cylinder head.

15) Remove the cylinder head gasket.
CAUTION:

Be careful not to scratch the mating surface of

cylinder head and cylinder block.

B: INSTALLATION

1) Install the cylinder head to the cylinder block.
CAUTION:

Be careful not to scratch the mating surface of

cylinder head and cylinder block.
NOTE:

Use a new cylinder head gasket.

(1) Clean the bolt threads and the bolt holes in

the cylinder block

CAUTION:

To avoid erroneous tightening of the bolts,

clean out the bolt holes sufficiently by blowing

with compressed air to eliminate engine cool-

ant etc.

(2) Apply a sufficient coat of engine oil to the

washer and bolt thread.

(3) Tighten all bolts to 40 N·m (4.1 kgf-m, 29.5

ft-lb) in alphabetical order.

ME-05983

(F)

(D)

(C)

(E)

(B)

(D)

(F)

(A)

(B)

(E)

(C)

(A)

ME-05983

(F)

(D)

(C)

(E)

(B)

(D)

(F)

(A)

(B)

(E)

(C)

(A)