Mitsubishi Evolution X. Manual - part 179

VALVE STEM SEAL

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ENGINE MECHANICAL

11A-47

INSTALLATION SERVICE POINTS

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>>A<< VALVE STEM SEAL INSTALLATION

CAUTION

• Valve stem seals cannot be reused.
• Do not damage the wall of the tappet hole when install-

ing the valve stem seal.

• Special tool MD998737 must be used to install the valve 

stem seal. Improper installation of the valve stem seal 
could result in oil leaking past the valve guide. 

1. Apply a small amount of engine oil to the press-fit part and 

lip part of the new valve stem seal.

2. Use special tool MD998737 to press-fit a new valve stem 

seal in the valve guide using the valve stem area as a guide.

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>>B<< VALVE SPRING INSTALLATION

Install the valve spring so that the painted side faces toward the 
camshaft.

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AC708679AC

AC308654AG

MD998737

Valve

Valve guide

Valve stem 
seal

AK502553

Paint mark position

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VALVE STEM SEAL

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ENGINE MECHANICAL

11A-48

>>C<< VALVE SPRING RETAINER LOCK 
INSTALLATION

In the same manner as removal, use special tool MD998772 
with special tool MB992090 and special tool MB992089 
attached to compress the valve spring, and install the valve 
spring retainer lock.

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>>D<< VALVE TAPPET INSTALLATION

1. Apply a small amount of engine oil to the valve tappets.

CAUTION

Be sure to install the valve tappets in the same position as 
before.
2. Install the valve tappet to the cylinder head.

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AC509271

AC

MD998772

MB992090

MB992089

AC509270

AC

Valve tappet

VALVE STEM SEAL

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ENGINE MECHANICAL

11A-49

>>E<< THRUST CAMSHAFT BEARING 
CAP/CAMSHAFT BEARING CAP/OIL FEEDING 
CAMSHAFT BEARING CAP INSTALLATION

1. Install the camshaft bearing caps to the cylinder heads.

NOTE: Because the thrust camshaft bearing cap and cam-
shaft bearing cap are the same in shape, check the cap 
number and additionally its symbol to identify the intake and 
exhaust sides for correct installation.

2. Tighten each camshaft bearing cap to the specified torque in 

the order of number shown in the figure in two or three 
steps.

Tightening torque: 12 

± 1 N⋅ m (107 ± 8 in-lb)

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AC506778

AC

8

8

7

7

6

6

5

5

4

4

3

3

2

2

1

1

E  5

Engine front

Camshaft bearing cap

Camshaft bearing cap

Bearing cap No.

Identification of intake side 
and exhaust side

VALVE STEM SEAL

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ENGINE MECHANICAL

11A-50

>>F<< CAMSHAFT BEARING/CAMSHAFT AND 
CAMSHAFT SPROCKET ASSEMBLY (EXHAUST 
SIDE) INSTALLATION

CAUTION

• Be careful not to drop the camshaft bearing.
• When installing the camshaft and camshaft sprocket 

assembly (exhaust side), be careful not to let the cam-
shaft bearing which is installed to the front cam bearing 
deviate from its position.

When replacing the camshaft bearing, according to the identifi-
cation mark of front camshaft bearing cap in the table below, 
select a camshaft bearing with the corresponding size. Note 
that the identification mark of camshaft bearing is stamped on 
the place shown in the figure.

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>>G<< FRONT CAMSHAFT BEARING CAP 
ASSEMBLY INSTALLATION

CAUTION

When the mounting bolts are tightened with the front cam-
shaft bearing cap tilted, the front camshaft bearing cap is 
damaged. Install the front camshaft bearing cap properly 
to the cylinder head and camshaft.
1. Install the front camshaft bearing cap to the cylinder head, 

and temporarily tighten the front camshaft bearing cap to the 
specified torque in the order of the figure (1).

Tightening torque: 17 

± 3 N⋅ m (13 ± 2 ft-lb)

2. Tighten the front camshaft bearing cap again to the specified 

torque in the order of the figure (2).

Tightening torque: 30 

± 2 N⋅ m (23 ± 1 ft-lb)

Front camshaft bearing cap

Camshaft bearing 
identification mark

Identification 
mark

Journal diameter 
mm (in)

1

40.000 - 40.008 
(1.5748 - 1.5751)

1

2

40.008 - 40.016 
(1.5751 - 1.5754)

2

3

40.016 - 40.024 
(1.5754 - 1.5757)

3

AC611697

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Front camshaft 
bearing cap

Identification
mark

AC708893

Notch

Identification mark

Oil hole

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AC511062

AC

4

3

2

1

4

3

2

1

(1)

(2)

Engine front

Front 
camshaft
bearing
cap
assembly