Page 65 of 558

ENGINE – Rocker Arms and Camshaft11-40
LASH ADJUSTER
Caution
(1) The lash adjusters are precision-engineered
mechanisms. Do not allow them to become
contaminated by dirt or other foreign substances.
(2) Do not attempt to disassemble the lash adjusters.
(3) Use only fresh diesel fuel to clean the lash adjusters.
(1) Prepare three containers and approximately five liters
of diesel fuel. Into each container, pour enough diesel
fuel to completely cover a lash adjuster when it is standing
upright. Then, perform the following steps with each lash
adjuster.
(2) Place the lash adjuster in container A and clean its outside
surface.
NOTE
Use a nylon brush if deposits are hard to remove.
(3) While gently pushing down the internal steel ball using
wire (0.5 mm in diameter) or special tool MD998442,
move the plunger through 5 to 10 strokes until it slides
smoothly. In addition to eliminating stiffness in the plunger,
this operation will remove dirty oil.
Caution
The steel ball spring is extremely weak, so the lash
adjuster’s functionality may be lost if the air bleed
wire is pushed in hard.
NOTE
If the plunger remains stiff or the mechanism appears
otherwise abnormal, replace the lash adjuster.
Outside
cleaningInside
cleaningFilling with
diesel fuel
A
B
C
Diesel
fuel
MD998442Diesel fuel
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ENGINE – Rocker Arms and Camshaft11-41
(4) Removal the lash adjuster from the container. Then, push
down the steel ball gently and push the plunger to eliminate
diesel fuel from the pressure chamber.
Caution
Make sure the oil hole in the side of the body is pointing
toward container A. Do not point the oil hole at yourself
or other people.
(5) Place the lash adjuster in container B. Then, gently push
down the internal steel ball using wire (0.5 mm in diameter)
or special tool MD998442 and move the plunger through
5 to 10 strokes until it slides smoothly. This operation
will clean the lash adjuster’s pressure chamber.
Caution
The steel ball spring is extremely weak, so the lash
adjuster’s functionality may be lost if the air bleed
wire is pushed in hard.
(6) Remove the lash adjuster from the container. Then, push
down the steel ball gently and push the plunger to eliminate
diesel fuel from the pressure chamber.
Caution
Make sure the oil hole in the side of the body is pointing
toward container A. Do not point the oil hole at yourself
or other people.
(7) Place the lash adjuster in container C. Then, gently push
down the internal steel ball using wire (0.5 mm in diameter)
or special tool MD998442.
Caution
Do not use container C for cleaning. If cleaning is
performed in container C, foreign matter could enter
the pressure chamber when chamber is filled with
diesel fuel.
(8) Stand the lash adjuster with its plunger at the top, then
push the plunger downward firmly until it moves through
its greatest possible stroke. Return the plunger slowly,
then release the steel ball and allow the pressure chamber
to fill with diesel fuel.
MD998442
Diesel fuel
MD998442Diesel fuel
MD998442
Diesel fuel
MD998442
Diesel fuel
MD998442Diesel fuel
Page 67 of 558
ENGINE – Rocker Arms and Camshaft11-42
(9) Remove the lash adjuster from the container, then stand
the lash adjuster with its plunger at the top. Push the
plunger firmly and check that it does not move. Also,
check that the lash adjuster’s height matches that of a
new lash adjuster.
NOTE
If lash adjuster contracts, perform the operations (7)
through (9) again to fill it with diesel fuel completely.
Replace the lash adjuster if it still contracts after performing
these steps.
(10)Stand the lash adjuster upright to prevent diesel fuel from
spilling out. Do not allow the lash adjuster to become
contaminated by dirt or other foreign matter. Fit the lash
adjuster onto the engine as soon as possible.
Page 68 of 558
ENGINE – Cylinder Head and Valves11-43
CYLINDER HEAD AND VALVES
REMOVAL AND INSTALLATION
Apply engine oil to all
moving parts before
installation.78 Nm → Loosen completely → 20 Nm + 90 + 90
1
2
3 4
5
6
78
9
10
11 12
1314
15
1617
1819 20
Removal steps
AD1. Cylinder head bolt
2. Cylinder head assembly
3. Cylinder head gasket
BC4. Retainer lock
5. Valve spring retainer
B6. Valve spring
7. Intake valve
BC8. Retainer lock
9. Valve spring retainer
B10. Valve springC11. Exhaust valve
A12. Valve stem seal
13. Valve spring seat
A14. Valve stem seal
15. Valve spring seat
16. Intake valve guide
17. Exhaust valve guide
18. Intake valve seat
19. Exhaust valve seat
20. Cylinder head
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ENGINE – Cylinder Head and Valves11-44
REMOVAL SERVICE POINTS
PRECAUTION FOR REMOVED PARTS
Keep removed parts in order according to the cylinder number
and intake/exhaust.
ACYLINDER HEAD BOLTS REMOVAL
Using the special tool, loosen the cylinder head bolts. Loosen
evenly, little by little.
BRETAINER LOCK REMOVAL
Store removed valves, springs and other parts, tagged to
indicate their cylinder No. and location for reassembly.
CVALVE HANDLING PRECAUTIONS
(1) Sodium reacts violently with water or moisture generation
heat and liberating hydrogen. It must be handled with
utmost care because otherwise the following dangerous
conditions may result:
Loss of eyesight if sodium gets in eyes.
Burns if soduim contact skin.
Fire hazard.
(2) Handling of Soduim-filled Exhaust Valves
Soduim-filled exhaust valves are not dangerous and may
be handled in the same way as ordinary valves unless
they are broken.
Never try to break the valves and expose soduim to the
air. When worn exhaust valves are to be discarded, have
them disposed of by a salvage company equipped with
special disposal system, notifying them that the valves
contain soduim.
Should the exhaust valves be broken, neutralize soduim
using the method described below, and discard the valves
in the same way as ordinary valves.
MB991654
MD998772
MD998735
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ENGINE – Cylinder Head and Valves11-45
(3) How to Neutralize Sodium
Place a container filled with more than 10 liters of water
in a well ventilated large space.
Wear rubber gloves and goggles, and carefully take out
broken valves from the cylinder head.
Put a broken valve in the water-filled container and quickly
get away from the container at least 2 or 3 m.
Caution
1. Valves must be neutralized one at a time.
2. Put a valve in the container only after soduim
in the preceding one has completely reacted with
water.
Keep fire away from the container during the
neutralization. The resulting hydrogen gas is highly
explosive.
When the reaction has finished (there is no more
generation of hydrogen gas), take the valves out of the
container with large tweezers or the like.
NOTE
The reaction occurs when water enters the cavity in the
valve. Hydrogen gas may be trapped inside the valve,
temporarily blocking the water passage. In such a case,
wait until hydrogen gas in released and remaining soduim
reacts with water.
After the neutralization of soduim, water in the container
contains soduim hydroxide and is highly alkaline. The
water solution should be disposed of according to local
regulations.
Caution
1. Do not let the solution contact the eyes or the
skin.
2. Should it get in the eyes, immediately flush them
with clean water thoroughly, and receive medical
attention. When it contacts the skin, wash with
ample amounts of clean water.
INSTALLATION SERVICE POINTS
AVALVE STEM SEAL INSTALLATION
(1) Install the valve spring seat.
(2) The special tool must be used to install the valve stem
seal. Improper installation could result in oil leaks past
the valve guide.
Caution
Do not reuse removed valve stem seals.
MD998737
Page 71 of 558
ENGINE – Cylinder Head and Valves11-46
BVALVE SPRING INSTALLATION
Direct the valve spring end with identification color toward
the spring retainer.
CRETAINER LOCK INSTALLATION
The valve spring, if excessively compressed, causes the
bottom end of the retainer to be in contact with, and damage,
the stem seal.
DCYLINDER HEAD BOLT INSTALLATION
(1) When installing the cylinder head bolts, check that the
shank length of each bolt meets the limit. If the limit is
exceeded, replace the bolt.
Limit: Max. 99.4 mm
(2) Apply engine oil to the bolt threads and to the washers.
(3) Using the special tool (MB991654) and according to the
tightening sequence, tighten the bolts to the specified
torque.
Tightening torque: 78 Nm
(4) Loosen all bolts fully.
(5) Retighten the loosened bolts to a torque of 20 Nm in
the specified tightening sequence.
MD998772
MD998735
6EN0782
Shank length
Timing belt side
Page 72 of 558

ENGINE – Cylinder Head and Valves11-47
(6) Make paint marks on the cylinder head bolt heads and
cylinder head.
(7) Give a 90° turn to the cylinder head bolts in the specified
tightening sequence.
(8) Give another 90° turn to the cylinder head bolts and make
sure that the paint mark on the head of each cylinder
head bolt and that on the cylinder head are on the same
straight line.
Caution
1. If the bolt is turned less than 90°, proper fastening
performance may not be expected. When
tightening the bolt, therefore, be careful to give
a sufficient turn to it.
2. If the bolt is overtightened, loosen the bolt
completely and then retighten it by repeating the
tightening procedure from step (1).
INSPECTION
CYLINDER HEAD
(1) Check the cylinder head gasket surface for flatness by
using a straightedge and thickness gauge.
Standard value: 0.05 mm
Limit: 0.2 mm
(2) If the service limit is exceeded, correct to meet
specification.
Grinding limit: *0.2 mm
* Includes combined with cylinder block grinding.
Cylinder head height (Specification when new):
131.9 – 132.1 mm
6AE0297
90°
Paint mark
90°
9EN0064