Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Service manual — part 179

ME(w/o STI)-97

Cylinder Block

MECHANICAL

6. CRANKSHAFT AND CRANKSHAFT

BEARING

1) Clean the crankshaft completely, and check it for

cracks using liquid penetrant tester. If defective, re-

place the crankshaft.

2) Measure warping of the crankshaft. If it exceeds

the limit, correct or replace it.
NOTE:

If a suitable V-block is not available, using just the

#1 and #5 crankshaft bearings on cylinder block,

position the crankshaft on cylinder block. Then,

measure the crankshaft bend using a dial gauge.
Crankshaft bend limit:

0.035 mm (0.0014 in)

3) Inspect the crank journal and crank pin for wear.

If they are not within the standard, replace the bear-

ing with a suitable (undersize) one, and replace or

grind to correct the crankshaft as necessary. When

grinding the crank journal or crank pin, finish them

to the specified dimensions according to the under-

size bearing to be used.
Crank pin:

Cylindricality

Limit

0.006 mm (0.0002 in)

Out-of-roundness

Limit

0.005 mm (0.0002 in)

Grinding limit (dia.)

To 51.750 mm (2.0374 in)

Crank journal:

Cylindricality

Limit

0.006 mm (0.0002 in)

Out-of-roundness

Limit

0.005 mm (0.0002 in)

Grinding limit (dia.)

To 59.758 mm (2.3527 in)

ME-00183

ME-00184

ME(w/o STI)-98

Cylinder Block

MECHANICAL

4) Use a thickness gauge to measure the thrust

clearance of crankshaft at #5 crank journal bearing.

If clearance exceeds the standard, replace the

bearing.
Crankshaft thrust clearance:

Standard

0.030 — 0.115 mm (0.0012 — 0.0045 in)

5) Inspect individual crankshaft bearings for signs

of flaking, seizure, melting and wear.

6) Measure the oil clearance on each crankshaft

bearing using plastigauge. If the measured value is

out of standard, replace the defective bearing with

an undersize one, and replace or grind to correct

the crankshaft as necessary.
Crankshaft oil clearance:

Standard

0.010 — 0.030 mm (0.0004 — 0.0012 in)

Unit: mm (in)

Crank journal diameter

Crank pin outer diameter

#1, #3

#2, #4, #5

Standard

Journal O.D.

59.984 — 60.008

(2.3616 — 2.3625)

59.984 — 60.008

(2.3616 — 2.3625)

51.976 — 52.000

(2.0463 — 2.0472)

Bearing size
(Thickness at center)

1.998 — 2.015

(0.0787 — 0.0793)

2.000 — 2.017

(0.0787 — 0.0794)

1.490 — 1.506

(0.0587 — 0.0593)

0.03 (0.0012)
Undersize

Journal O.D.

59.962 — 59.978

(2.3607 — 2.3613)

59.962 — 59.978

(2.3607 — 2.3613)

51.954 — 51.970

(2.0454 — 2.0461)

Bearing size
(Thickness at center)

2.017 — 2.020

(0.0794 — 0.0795)

2.019 — 2.022

(0.0795 — 0.0796)

1.504 — 1.512

(0.0592 — 0.0595)

0.05 (0.0020)
Undersize

Journal O.D.

59.942 — 59.958

(2.3599 — 2.3605)

59.942 — 59.958

(2.3599 — 2.3605)

51.934 — 51.950

(2.0447 — 2.0453)

Bearing size
(Thickness at center)

2.027 — 2.030

(0.0798 — 0.0799)

2.029 — 2.032

(0.0799 — 0.0800)

1.514 — 1.522

(0.0596 — 0.0599)

0.25 (0.0098)
Undersize

Journal O.D.

59.742 — 59.758

(2.3520 — 2.3527)

59.742 — 59.758

(2.3520 — 2.3527)

51.734 — 51.750

(2.0368 — 2.0374)

Bearing size
(Thickness at center)

2.127 — 2.130

(0.0837 — 0.0839)

2.129 — 2.132

(0.0838 — 0.0839)

1.614 — 1.622

(0.0635 — 0.0639)

ME-00322

ME(w/o STI)-99

Intake and Exhaust Valve

MECHANICAL

21.Intake and Exhaust Valve

A: SPECIFICATION

Refer to “Cylinder Head” for removal and installa-

tion procedures of the intake and exhaust valves.

<Ref. to ME(w/o STI)-68, REMOVAL, Cylinder

Head.> <Ref. to ME(w/o STI)-68, INSTALLATION,

Cylinder Head.>

ME(w/o STI)-100

Piston

MECHANICAL

22.Piston

A: SPECIFICATION

Refer to “Cylinder Block” for removal and installa-

tion procedures of pistons. <Ref. to ME(w/o STI)-

77, REMOVAL, Cylinder Block.> <Ref. to ME(w/o

STI)-81, INSTALLATION, Cylinder Block.>