Mitsubishi Lancer Evolution 7. Manual — part 166
ENGINE OVERHAUL -
Cylinder Head and Valve
11B-41
REMOVAL SERVICE POINTS
A
A" CYLINDER HEAD BOLT REMOVAL
Remove the cylinder head bolt using the special tool.
A
B" RETAINER LOCK REMOVAL
Compress the valve spring using the special tool, and remove
the retainer lock.
NOTE
Attach a tag indicating the cylinder No. and installation position
onto the parts including the removed valve and springs so
that they can be reassembled later.
INSTALLATION SERVICE POINTS
"
AA VALVE STEM SEAL INSTALLATION
1. Install the valve spring seat.
2. Install the valve.
3. Apply a small amount of engine oil on the valve stem
seal.
4. Using the valve stem as a guide, press in the valve guide
using the special tool.
Caution
Improper installation of the valve stem seal can lead
to oil reduction, so always install using the special
tool.
NOTE
Note that the valve stem seals for the intake side and
exhaust side are different.
MB991654
MD998772
MD998735
MB998737
Body colour:
Grey
Body colour:
Grayish-green
Intake side
Exhaust side
ENGINE OVERHAUL -
Cylinder Head and Valve
11B-42
"
BA VALVE SPRING INSTALLATION
Install the valve spring so that the painted surface faces the
rocker arm.
"
CA RETAINER LOCK INSTALLATION
Compress the valve spring using the special tool, and install
the retainer lock.
"
DA CYLINDER HEAD BOLT INSTALLATION
1. Before reusing the cylinder head bolt, confirm that the
bolt’s underhead length is less than the limit value.
Replace the bolt if it exceeds the limit value.
Limit value: 99.4 mm
2. Apply engine oil on the bolt threads and washer.
NOTE
Use the special tool to tighten the cylinder head bolt.
Painted
surface
Spring
retainer
Stem
seal
Spring
seat
MD998772
MD998735
Underhead length
MB991654
ENGINE OVERHAUL -
Cylinder Head and Valve
11B-43
3. Following the tightening order, tighten at 78 ± 2 N•m.
4. Completely loosen the bolts.
5. Next, following the tightening order, tighten the loosened
bolts at the torque 20 ± 2 N•m again.
6. Make paint marks on the cylinder head bolt’s head and
cylinder head.
7. Following the tightening order, tighten the cylinder head
by 90_.
8. Tighten by another 90_, and confirm that the paint mark
made on the cylinder head bolt’s head and the paint
mark on the cylinder head are positioned on the same
line.
Caution
(1) If the tightening angle is less than 90_, the
connection performance may not be attained, so
take special care to the tightening angle when
tightening.
(2) If the tightening angle is larger than the specified
value, completely loosen the bolt and start again
from step 1.
INSPECTION
1. CYLINDER HEAD
(1) Before cleaning the cylinder head, check it for water
leaks, gas leaks, damage or cracks.
(2) Completely remove the oil, water deposits, sealant
and carbon, etc. After cleaning the oil path, blow
air and confirm that there is not clogging.
(3) Using a straight edge and thickness gauge, inspect
the flatness of the bottom of the cylinder head for
strain.
If the strain exceeds the limit value, grind the end
and correct the flatness.
Standard value for lower surface strain: 0.05 mm
Limit value for lower surface strain: 0.2 mm
Grinding limit value: 0.2 mm
Cylinder head height (standard value for new part):
131.9 - 132.1 mm
Caution
The grinding limit is within 0.2 mm together with
the combined cylinder block.
Timing belt side
8
6
1
3
9
10
4
2
5
7
90_
90_
Paint marks
ENGINE OVERHAUL -
Cylinder Head and Valve
11B-44
2. VALVE
(1) If there is a faulty contact, one-sided contact or
improper seating with the valve seat, correct the valve
seat.
(2) Replace the valve if the margin exceeds the limit
value.
Standard value:
Intake
1.0 mm
Exhaust
1.5 mm
Limit value:
Intake
0.5 mm
Exhaust
1.0 mm
(3) Measure the total length of the valve, and replace
the valve if the length exceeds the limit value.
Standard value:
Intake
109.50 mm
Exhaust
109.70 mm
Limit value:
Intake
109.00 mm
Exhaust
109.20 mm
3. VALVE SPRING
(1) Measure the free height of the spring, and replace
the valve spring if the height exceeds the limit value.
Standard value: 48.3 mm
Limit value: 47.3 mm
(2) Measure the spring squareness, and replace the valve
spring if the inclination exceeds the limit value.
Standard value: 1.5_ or less
Limit value: 4_
4. VALVE GUIDE
Measure the clearance between the valve guide and valve
stem. If the clearance exceeds the limit value, replace
the valve guide, valve or both parts.
Standard value:
Intake
0.02 - 0.05 mm
Exhaust
0.05 - 0.09 mm
Limit value:
Intake
0.10 mm
Exhaust
0.15 mm
Contact
(Must be at
centre of face)
Margin
Total valve length
Squareness
Free height
Valve
guide
Stem outer
diameter
Guide inner
diameter
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