Mitsubishi Grandis. Manual — part 661

CYLINDER HEAD AND VALVES

ENGINE OVERHAUL

11B-39

REMOVAL SERVICE POINTS
<<A>> CYLINDER HEAD BOLTS
REMOVAL

Using special tool Cylinder head bolt wrench
(MB991654), loosen the cylinder head bolts. Loosen
each bolt evenly, little by little, by two or three steps.

<<B>> RETAINER LOCK REMOVAL

1. Set special tool Valve spring compressor

(MD998735) as illustrated to compress the valve
spring. Remove the retainer lock.

2. Relieve the spring tension and remove the valve,

retainer, spring, etc. Store removed valves,
springs, and other parts, tagged to indicate their
cylinder number and location for assembly.

INSTALLATION SERVICE POINTS
>>A<< VALVE STEM SEAL
INSTALLATION

CAUTION

The special tool must be used to install the valve
stem seal. Improper installation could result in oil
leaking past the valve guide.
1. Install the valve spring seat.
2. Using special tool Valve stem seal installer

(MD998774), install a new valve stem seal.

>>B<< VALVE SPRING INSTALLATION

Install the valve spring with its identification color
painted end (larger pitch side) upward (toward the
valve spring retainer).

Identification:

<Intake> Light blue
<Exhaust> Orange

AK300162

MB991654

AD

AK300163

MD998735

AD

AK300164

MD998774

AD

AK300717AB

Painted end

CYLINDER HEAD AND VALVES

ENGINE OVERHAUL

11B-40

>>C<< RETAINER LOCK INSTALLATION

CAUTION

Do not compress the valve spring excessively. It
can damage the stem seal.
1. Set special tool Valve spring compressor

(MD998735) as illustrated to compress the valve
spring. Install the retainer locks.

2. Relieve the spring tension. Check that the retainer

locks are seated correctly.

AK300163

MD998735

AD

CYLINDER HEAD AND VALVES

ENGINE OVERHAUL

11B-41

>>D<< CYLINDER HEAD BOLT
INSTALLATION

1. When the removed cylinder head bolts are to be

reused, check that the shank length of each bolt
meets the limit. If it exceeds the limit, replace the
bolts.

Limit: 99.4 mm

2. Apply engine oil to the thread of the bolts and to

the washers.

3. Using special tool Cylinder head bolt wrench

(MB991654) tighten the bolts to the specified
torque, using the tightening sequence shown.

Tightening torque: 78

± 2 N⋅m

4. Loosen all bolts fully in the reverse order of

tightening.

5. Retighten the loosened bolts to in the tightening

sequence shown.

Tightening torque: 20

± 2 N⋅m

6. Make a paint mark across each bolt head and

cylinder head.

7. Tighten the cylinder head bolts 90 degrees in the

specified order.

CAUTION

• If the bolt is turned less than 90 degrees,

proper fastening performance may not be
achieved. Be careful to turn each bolt exactly
90 degrees.

• If the bolt is overtightened, loosen the bolt

completely and then retighten it by repeating
the tightening procedure from step 1.

8. Tighten the bolts another 90 degrees in the same

order as in step 7, and check that the paint marks
on the cylinder head bolt are aligned with the paint
marks on the cylinder head.

INSPECTION

M1113007000549

CYLINDER HEAD

1. Check the cylinder head gasket surface for

flatness by using a straight edge and feeler
gauge.

Standard value: 0.03 mm
Limit: 0.2 mm

2. If it exceeds the limit, correct to meet

specification.

Grinding limit: *0.2 mm

* Includes combined with cylinder block

grinding.

AK300591AB

Shank length

AK300165

MB991654

AD

AK304589AB

4

2

5

7

10

6

1

3

9

8

Timing belt side

AK300166

90˚

90˚

Paint mark

AD

AK300167

CYLINDER HEAD AND VALVES

ENGINE OVERHAUL

11B-42

Cylinder head height (Specification when
new): 120 mm

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
<Exhaust> 1.2 mm

Minimum limit:

<Intake> 0.5 mm
<Exhaust> 0.7mm

3. Measure the valve's total length. If the

measurement is less than the limit, replace the
valve.

Standard value:

<Intake> 111.33 mm
<Exhaust> 113.54 mm

Minimum limit:

<Intake> 110.83 mm
<Exhaust> 113.04 mm

VALVE SPRING

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

than the limit, replace.

Standard value:

<Intake> 54.8 mm
<Exhaust> 56.1 mm

Minimum limit:

<Intake> 53.8 mm
<Exhaust> 55.1 mm

2. Measure the squareness of the spring. If it

exceeds the limit, replace.

Standard value: 2 degrees or less
Limit: 4 degrees

VALVE GUIDE

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> 0.02

− 0.04 mm

<Exhaust> 0.04

− 0.06 mm

Limit:

<Intake> 0.10 mm
<Exhaust> 0.15 mm

AK300593AB

Margin

Contact
(Should be at
center of face)

AK304590AB

Total length

AK300718AB

Out of square

Free height

AK300168

Guide inside diameter

Stem diameter

Valve
guide

AE