Mitsubishi Outlander GS45X. Manual - part 1224

CYLINDER HEAD AND VALVES

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ENGINE OVERHAUL <3.0L ENGINE>

11D-49

INSPECTION

M1113007002556

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CYLINDER HEAD

1. Check the cylinder head for water leakages, gas leakages, 

damages or cracks before cleaning.

2. Remove oil, water deposits, sealants, carbon deposits 

completely. Blow air after cleaning the oil passage to check 
whether the oil passage is not clogged.

3. Check the flatness of the lower surface of the cylinder head 

for distortions using a straight edgs gauge and thickness 
gauge. Unless being within the limit, the distortion must be 
ground and corrected.

Standard value: 0.03 mm (0.0012 inch)
Limit: 0.05 mm (0.002 inch)
Cylinder head height (specification when new):
120 mm (4.7 inches)

CAUTION

*The grinding limit must be within 0.15mm including the 
cylinder block.

Grinding limit: *0.15 mm (0.006 inch)

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CYLINDER HEAD BOLT

1. Check in the following procedure before reusing the cylinder 

head bolt.

(1) Measure the outside diameter "A".
(2) Measure the smallest outside diameter "B" within the 

range "X" shown in the illustration.

(3) If the difference of outside diameter of thread exceeds 

the limit, replace the cylinder head bolt.

Limit: 0.1mm (0.0039 inch)

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VALVE

1. Check the valve seat contact. Valve seat contact should be 

uniform at the center of the valve face. If incorrect, reface 
using a valve refacer.

2. If the margin is below the limit, replace the valve.

Standard value:

Intake 1.0 mm (0.03 inch)
Exhaust 1.2 mm (0.04 inch)

Minimum limit:

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

AK600916

AK700001AB

34 mm
(1.34 in)

17 mm
(0.67 in)

A

B

B

X

AK600792

Margin

Contact
(should be at 
center of face)

AC

CYLINDER HEAD AND VALVES

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

than the limit, replace the valve.

Standard value:

Intake 111.84 mm (4.403 inches)
Exhaust 114.04 mm (4.490 inches)

Minimum limit:

Intake 111.34 mm (4.384 inches)
Exhaust 113.54 mm (4.470 inches)

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VALVE SPRING

1. Measure the free height of the spring. If it is less than the 

limit, replace.

Standard value:

Intake 63.77 mm (2.5111 inches)
Exhaust 59.90 mm (2.358 inches)

Minimum limit:

Intake 62.77 mm (2.471 inches)
Exhaust 58.90 mm (2.319 inches)

2. Measure the squareness of the spring. If it exceeds the limit, 

replace.

Standard value: 2 degrees or less
Limit: 4 degrees

3. Valve spring load / installed height.

Standard value: 245.2 N (55.13 Ib) / 49.2 mm (1.94 in)

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VALVE GUIDE INSPECTION

Measure the clearance between the valve guide and valve 
stem. If it exceeds the limit, replace the valve guide or valve, or 
both.

Standard value:

Intake 0.020 

− 0.047 mm (0.0008 − 0.0018 inch)

Exhaust 0.035 

− 0.062 mm (0.0014 − 0.0024 inch)

Limit:

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

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VALVE GUIDE REPLACEMENT PROCEDURE

1. Using a press, remove the valve guide toward the cylinder 

block.

CAUTION

Do not install a valve guide of the same size again.
2. Rebore the valve guide hole of the cylinder head so that it 

fits the press-fitted oversize valve guide.

Valve guide hole diameters

0.05 oversize: 11.050 

− 11.068 mm (0.4351 − 0.4357 

inch)

AK600793AC

Total length

AK600794

Out of square

Free hight

AC

AK600799

Guide inside diameter

Stem diameter

AC

Valve
guide

CYLINDER HEAD AND VALVES

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11D-51

3. Press-fit the valve guide until it projects by the specified 

amount.

Protrusion: 16.7 

− 17.3 mm (0.66 − 0.68 inch)

NOTE: When press-fitting the valve guide, work from the 
cylinder head top surface.
NOTE: Pay attention to the difference in length of the valve 
guides. [Intake side: 45.5 mm (1.79 inches); exhaust side: 
52.5 mm (2.07 inches)]
NOTE: After installing the valve guides, insert new valves in 
them to check for smooth operation. 

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VALVE SEAT INSPECTION

Assemble the valve, then measure the contact width. If the 
measurement exceeds the specified limit, replace the valve 
seat.

Standard value: 0.9 

− 1.3 mm (0.04 − 0.05 inch)

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VALVE SEAT REPLACEMENT PROCEDURE

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.

Intake seat ring hole diameters

0.3 oversize:

36.300 

− 36.325 mm (1.4292 − 1.4301 inches)

Exhaust seat ring hole diameters

0.3 oversize:

32.300 

− 32.325 mm (1.2717 − 1.2726 inches)

AK600917AC

Protrusion

AK600918AC

Contact width

Valve seat

AK600795

Cut

AC

0.5 – 1.0 mm
(0.02 – 0.04 in)

0.5 – 1.0 mm
(0.02 – 0.04 in)

AK600796

Valve seat
height

AC

Oversize hole
diameter

CYLINDER HEAD AND VALVES

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3. Before fitting the valve seat, either heat the cylinder head up 

to approximately 250

°C (482°F) or cool the valve seat in 

liquid nitrogen, to prevent the cylinder head bore from 
galling.

4. Using a valve seat cutter, correct the valve seat to the 

specified width and angle.
See "VALVE SEAT RECONDITIONING PROCEDURE" on 
the previous page.

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VALVE SEAT RECONDITIONING PROCEDURE

1. Before correcting the valve seat, check for clearance 

between the valve guide and valve and, if necessary, 
replace the valve guide.

2. Using the seat grinder, correct to obtain the specified seat 

width and angle.

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

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

AK600919

65˚

30˚

30˚

43.5 ˚– 44˚

65˚

AE

0.9 – 1.3 mm
(0.36 – 0.51 in)

43.5 ˚– 44˚