Mitsubishi Montero (2004+). Manual — part 118

CYLINDER HEAD AND VALVES

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ENGINE OVERHAUL

11B-31

CAUTION

Always use the special tool to install the valve stem seal.
Improperly installed valve stem seals may leak oil.
2. Using special tool MD998774, install a new stem seal to the

valve guide.

.

>>B<< VALVE SPRING INSTALLATION
Install the valve spring end with its identification color toward
the spring retainer.

.

>>C<< RETAINER LOCK INSTALLATION
Using special tool MD998772, compress the valve spring and
insert the retainer lock into position.

.

AKX00618AB

MD998774

AKX00718

SPRING SEAT

SPRING
RETAINER

IDENTIFI-
CATION
COLOR

STEM SEAL

AB

AKX00617

MD998772

AB

CYLINDER HEAD AND VALVES

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ENGINE OVERHAUL

11B-32

>>D<< CYLINDER HEAD BOLT INSTALLATION

CAUTION

Attach the head bolt washer in the direction shown in the
figure.
1. Tighten the bolts in the illustrated sequence two or three

rounds.

Tightening torque: 108

± 5 N⋅m (80 ± 4 ft-lb)

2. Back off the bolts once and tighten them to the specified

torque in the same procedure as shown in step (1).

INSPECTION

M1113007000442

.

CYLINDER HEAD
1. Check the cylinder head gasket surface for flatness by using

a straightedge in the directions of A through G shown in the
illustration.

Standard value: 0.03 mm (0.0012 inch)
Limit: 0.2 mm (0.007 inch)

2. If the service limit is exceeded, correct to meet the

specification.

Grinding limit: *0.2 mm (0.007 inch)

3. *If the service limit is exceeded, correct to meet the

specification.

Cylinder head height (specification when new):
120 mm (4.7 inches)

.

AKX01452AB

FRONT

MD998051

HEAD
BOLT
WASHER

RIGHT
BANK

LEFT
BANK

AKX00733

CYLINDER HEAD AND VALVES

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ENGINE OVERHAUL

11B-33

VALVE
1. Check the valve face for correct contact. If incorrect, reface

using a valve refacer. The valve should make a uniform
contact with the seat at the center of the valve face.

2. If the margin exceeds the service minimum limit, replace the

valve.

Standard value:

<Intake> 1.0 mm (0.04 inch)
<Exhaust> 1.2 mm (0.05 inch)

Minimum limit:

<Intake> 0.5 mm (0.02 inch)
<Exhaust> 0.7 mm (0.03 inch)

3. Measure the valve's total length. If the measurement is less

than specified, replace the valve.

Standard value:

<Intake> 110.30 mm (4.343 inches)
<Exhaust> 112.11 mm (4.414 inches)

Minimum limit:

<Intake> 109.80 mm (4.323 inches)
<Exhaust> 111.61 mm (4.394 inches)

.

VALVE SPRINGS
1. Measure the free height of the spring and, if it is smaller than

the minimum limit, replace the spring.

Standard value: 51.0 mm (2.01 inches)
Minimum limit: 50.0 mm (1.97 inches)

2. Measure the squareness of the spring and, if the limit is

exceeded, replace the spring.

Standard value: 2

° or less

Limit: 4

°

.

VALVE GUIDES
Measure the clearance between the valve guide and valve
stem. If the limit is exceeded, replace the valve guide, valve, or
both.

Standard value:

<Intake> 0.02

− 0.05 mm (0.0008 − 0.0019 inch)

<Exhaust> 0.04

− 0.07 mm (0.0016 − 0.0027 inch)

Limit:

<Intake> 0.10 mm (0.003 inch)
<Exhaust> 0.15 mm (0.005 inch)

.

AKX00619

MARGIN

VALVE SEAT
CONTACT

AB

AKX00624

AKX00607

2˚

FREE
HEIGHT

AB

AKX00714

VALVE
GUIDE

STEM OUTSIDE
DIAMETER

GUIDE INSIDE DIAMETER

AB

CYLINDER HEAD AND VALVES

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ENGINE OVERHAUL

11B-34

VALVE SEAT
Assemble the valve, then measure the valve stem projection
between the end of the valve stem and the spring seating sur-
face. If the measurement exceeds the specified limit, replace
the valve seat.

Standard value:

<Intake> 48.30 mm (1.9021 inches)
<Exhaust>51.71 mm (2.039 inches)

Limit:

<Intake> 48.80 mm (1.921 inches)
<Exhaust> 52.01 mm (2.048 inches)

.

VALVE SEAT RECONDITIONING PROCEDURE

CAUTION

Before correcting the valve seat, check the clearance
between the valve guide and valve and, if necessary,
replace the valve guide.
1. Using the special tool or a seat grinder, correct to obtain the

specified seat width and angle.

2. After correcting the valve seat, lap the valve and valve seat

using lapping compound. Then, check the valve stem
projection.

.

VALVE SEAT REPLACEMENT PROCEDURE

CAUTION

Before replacing the valve seat, check the valve guide and,
if necessary, replace the valve guide.
1. Cut the valve seat from the inside to thin the wall thickness.

Then, remove the valve seat.

2. Rebore the valve seat hole in the cylinder head to a selected

oversize valve seat diameter.

Seat ring hole diameter:

Intake valve
0.3 oversize 37.80

− 37.83 mm (1.4882 − 1.4894

inches)

0.6 oversize 38.10

− 38.13 mm (1.5000 − 1.5012

inches)

Exhaust valve
0.3 oversize 34.80

− 34.83 mm (1.3701 − 1.3713

inches)

0.6 oversize 35.10

− 35.13 mm (1.3819 − 1.3831

inches)

AKX00695

SPRING SEATING
SURFACE

VALVE STEM END

VALVE STEM
PROJECTION

AB

AK101830AB

0.9 – 1.3 mm
(0.04 – 0.05 in)

65˚

65˚

15˚

25˚

43.5˚ – 44˚

0.9 – 1.3 mm
(0.04 – 0.05 in)

AKX00610

0.5 – 1 mm
(0.020 – 0.039 in)

0.5 – 1 mm (0.020 – 0.039 in)

CUT
AWAY

AB

AKX00611

HEIGHT OF
SEAT RING

OVERSIZE DIAMETER

AB