Mitsubishi Evolution X. Manual — part 201

AK602942AE

Ø2.0 to Ø3.0 mm
(0.08 to 0.12 in)

Timing chain side

CYLINDER HEAD AND VALVES

TSB Revision

ENGINE OVERHAUL

11B-51

3. As shown in the illustration, apply a

φ2.0 to 3.0 mm (0.08 to

0.12 inch) of sealant (Three bond 1217G [Mitsubishi
Genuine Part No.1000A923] or equivalent) to the top face of
cylinder block.

4. Install the cylinder head gasket.

NOTE: Check that the center of the liquid gasket is located
toward the cylinder gasket in the position specified in the
illustration.

5. As shown in the illustration, apply a

φ2.0 to 3.0 mm (0.08 to

0.12 inch) of sealant (Three bond 1217G [Mitsubishi
Genuine Part No.1000A923] or equivalent) to the top face of
cylinder head gasket.

6. Install the cylinder head assembly.

.

>>E<< CYLINDER HEAD BOLT INSTALLATION

1. Install new cylinder head bolts and washers in the following

procedure.
NOTE: Cylinder head bolts and washers must not be
reused.

2. Apply an appropriate amount of engine oil to top and bottom

surfaces of washers and threaded portion of bolts.

AK603866

Cylinder head bolt

Washer

AE

3. Install cylinder head bolts to the cylinder head.

NOTE: Bolts and washers are different parts for bolts on the
timing chain side.

AK502392

8

10

9

7

3

5

1

2

6

4

AD

Timing chain side

CYLINDER HEAD AND VALVES

TSB Revision

ENGINE OVERHAUL

11B-52

4. Tighten cylinder head bolts in several steps to the specified

torque according to the assembly order shown.

Specified torque: 35

± 2 N⋅ m (26 ± 1 ft-lb)

AK502523AD

Paint mark

Paint mark

90˚

90˚

Paint mark

Paint mark

5. Put a paint mark on all of cylinder head bolt heads and

cylinder head.

CAUTION

• When the tightening angle is smaller than the specified

tightening angle, the appropriate tightening capacity
cannot be secured.

• When the tightening angle is larger than the specified

tightening angle, remove the bolt to start from the
beginning again according to the procedure.

6. Tighten the cylinder head 90

° according to the tightening

order.
Tighten it further 90

° and make sure that the paint mark on

the cylinder head bolt is in a straight line with that on the
cylinder head.

INSPECTION

M1113007001876

.

CYLINDER HEAD

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

damage or cracks before cleaning.

2. Completely remove oil, scale, sealant, carbon, etc. After

cleaning oil passages, blow air to make sure that they are
not clogged.

AK502740

CAUTION

The grinding limit shall be within 0.2 mm (0.01 inch) in
combination with the cylinder block to be assembled.
3. For the flatness on the cylinder head bottom, measure

distortion using a straight edge and thickness gauge. If the
distortion exceeds the limit, grind and repair it.

Distortion on bottom

Standard value: Within 0.05 mm (0.002 inch)
Limit: 0.2 mm (0.01 inch)
Grinding limit: 0.2 mm (0.01 inch)

Cylinder head height: 128.5 mm (5.06 inches)

.

CYLINDER HEAD AND VALVES

TSB Revision

ENGINE OVERHAUL

11B-53

VALVE

AK305408AD

Margin

The bottom of valve
seat contact facet

1. Repair the valve seat if contact with the valve seat is poor,

uneven or broken.

2. Measure the margin.

If the limit is exceeded, replace the valve.

Standard value:

Intake 1.022 mm (0.0402 inch)
Exhaust 1.094 mm (0.0431 inch)

Limit:

Intake 0.522 mm (0.0206 inch)
Exhaust 0.594 mm (0.0234 inch)

AK305409AD

Length

3. Measure overall length of the valve.

If the limit is exceeded, replace the valve.

Standard value:

Intake 113.18 mm (4.456 inches)
Exhaust 105.89 mm (4.169 inches)

Limit:

Intake 112.68 mm (4.436 inches)
Exhaust 105.39 mm (4.149 inches)

.

VALVE SPRING

AK305410AD

Free height

Squareness

1. Measure free height of the spring.

If the limit is exceeded, replace the spring.

Standard value: 51.5 mm (2.03 inch)
Limit: 51.0 mm (2.01inch)

2. Measure squareness of the spring.

If the inclination exceeds the limit, replace the spring.

Standard value: 2

° or less

Limit: 4

°

.

VALVE GUIDE

AK300168

Guide inside diameter

Stem diameter

Valve
guide

AF

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

Standard value:

Intake 0.020

− 0.047 mm (0.0008 − 0.0019 inch)

Exhaust 0.030

− 0.057 mm (0.0012 − 0.0022 inch)

Limit:

Intake 0.10 mm (0.004 inch)
Exhaust 0.15 mm (0.006 inch)

.

CYLINDER HEAD AND VALVES

TSB Revision

ENGINE OVERHAUL

11B-54

VALVE SEAT

AK601281AD

Contact width

Valve seat

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

Standard value

Intake: 1.16

− 1.46 mm (0.046 − 0.058 inch)

Exhaust: 1.35

− 1.65 mm (0.053 − 0.065 inch)

CAUTION

If the variation in the width exceeds 0.2 mm (0.01 inch)
even if the contact width is within the standard value,
replace or correct the valve seat.

REPAIR PROCEDURE OF VALVE SEAT

1. Check clearance between valve guide and valve and

replace the valve guide if necessary before repairing the
valve seat.

AK503333AD

30˚

60˚

30˚

1.16 – 1.46 mm
(0.053 – 0.065 in)

45˚

45˚

1.35 – 1.65 mm
(0.046 – 0.058 in)

2. Repair the valve seat so that seat width and seat angle are

to the specified shape.

3. Lap valve and valve seat with lapping compound after

repairing valve seat.

REPLACEMENT PROCEDURE OF VALVE SEAT

AK300719AE

Cut

0.5 – 1 mm
(0.02 – 0.04 in)

0.5 – 1 mm
(0.02 – 0.04 in)

1. Scrape the valve seat to be replaced from inside to make its

wall thickness thin before pulling out.

AK300720AE

Oversize hole
diameter

Valve seat
height

2. Repair the valve seat hole of the cylinder head to match it

with the diameter of the oversize valve seat to be press
fitted.

Intake valve seat bore diameter:

0.3 O.S.: 36.22

− 36.24 mm (1.426 − 1.427 inches)

Exhaust valve seat bore diameter:

0.3 O.S.: 30.22

− 30.24 mm (1.190 − 1.191 inches)

3. Press fit the valve seat, taking care not to score the cylinder

head bore at room temperature.

4. Ream the valve seat.

Refer to "Repair procedure of valve seat."