Mitsubishi S6S-Y3T61HF, S6S-Y3T62HF Service Manual

Printed in Japan

Pub. No.

Pub. No.

SERVICE MANUAL

SERVICE MANUAL

Pub. No.

August 2008

August 2008

99616-25000

99616-25000

99616-25000

for HYUNDAI HEAVY INDUSTRIES CO.,LTD.

for HYUNDAI HEAVY INDUSTRIES CO.,LTD.







Pub.No. 99616-25000

INTRODUCTION

This service manual describes the specifications, maintenance and service procedures

for Mitsubishi diesel engines.

To maintain the performance of the engine for many years and to ensure safe operation,
it is important to use the engine correctly and conduct regular inspection and maintenance,
and also to take necessary measures which involves the disassembly, inspection, repair and
reassembly of the engine and engine parts.

Read this manual carefully and understand the work procedures fully before
disassembling, inspecting, repairing or reassembling the engine.

The contents of the manual are based on the engine models that are being produced at
the time of publication. Due to improvements made thereafter, the actual engine that you
work on may differ partially from the one described in this manual.

INTRODUCTION

I

How to use this manual

This service manual consists of several Groups, which are arranged so as to allow you to make reference quickly to
specifications, maintenance standards, adjustment procedures and service procedures including methods for disassembly,
inspection, repair and reassembly of the Mitsubishi Diesel Engine (standard model for land use).
A short summary describing the content of each Group is given in the General Contents page, and there is also a detailed table
of contents at the beginning of each Group.
Regarding the procedures for operation and periodical maintenance of the engine, refer to the Operation and Maintenance
Manual. For information on the engine components and ordering of service parts, refer to the Parts Catalogue. Structure and
function of the engine are described in the relevant training manuals.

Methods of presentation

(1) Index numbers allotted to parts in exploded views are not only a call-out of part names listed in the text but also an indi-

cation of the sequence of disassembly.

(2) Inspections to be conducted during disassembly process are indicated in boxes in the relevant exploded views.
(3) Maintenance standards required for inspection and repair works are indicated in the appropriate positions in the text.

They are also collectively indicated in Group 2, the General Contents group.

(4) Fasteners to be tightened in “wet” condition, or with engine oil applied, are identified by [Wet] placed after tightening

torque values. If no such indication is suffixed, the fastener should be tightened in “dry” condition, or without lubricating
with engine oil.

(5) In this manual, important safety or other cautionary instructions are emphasized with the following marks headed.

Indicates an immediately hazardous situation which, if not avoided, will result in death or serious injury.

Indicates a potentially hazardous situation which, if not avoided, could result in death or serious injury.

Indicates an immediately hazardous situation which, if not avoided, may result in minor or moderate injury.

Indicates a potentially hazardous situation which, if not avoided, can result in property damage.

Emphasizes important matter, or indicates information useful for operation or maintenance of the engine.

DANGER

WARNING

CAUTION

CAUTION

Note:

INTRODUCTION

II

Terms used in this manual

Nominal

means the rated (design) size or magnitude of a part to be measured.

Standard

means the quantitative requirement for dimension of a part, clearance between parts and performance. This is given in a form of
tolerance. Therefore, the values shown are not in agreement with the design values.

Limit

means that, if this value is reached, the part must be repaired or replaced with a new part.

Abbreviations

• BTDC: Before Top Dead Center

• ATDC: After Top Dead Center

• BBDC: Before Bottom Dead Center

• ABDC: After Bottom Dead Center

• TIR: Total Indicated Runout

• API: American Petroleum Institute

• ASTM: American Society for Testing and Materials

• JIS: Japanese Industrial Standards

• LLC: Long Life Coolant

• MIL: Military Specifications and Standards (U.S.A.)

• MSDS: Material Safety Data Sheet

• SAE: Society of Automotive Engineers (U.S.A.)

Units of measurement

Measurements are based on the International System of Units (SI), and their converted metric values are indicated in
parentheses {}. For metric conversion, the following rates are used.

• Pressure: 1 MPa = 10.197 kgf/cm²

• Torque: 1 N·m = 0.10197 kgf·m

• Force: 1 N = 0.10197 kgf

• Horsepower: 1 kW = 1.341 HP = 1.3596 PS

• Meter of mercury: 1 kPa = 0.7 cmHg

• Meter of water: 1 kPa = 10.197 cmH

2O (cmAq)

• Rotational speed: 1min

-1

= 1 rpm

INTRODUCTION

III

Safety Cautions

Fire and explosion

Keep flames away

Store fuel and engine oil in a well
ventilated designated area.
Make sure that the caps of fuel and
engine oil containers are tightly
closed.
Do not use flames, do not smoke,
and do not work near a heater or other fire hazard
where fuel or oil is handled or when cleaning solvent is
being used for washing parts.
Wipe off spilled fuel, oil and LLC immediately and thor­oughly. Spilled fuel, oil and LLC may ignite and cause
a fire.

Keep surrounding area tidy and clean

Do not leave combustible or explosive materials, such
as fuel, engine oil and LLC, near the engine. Such sub­stances can cause fire or explosion.
Remove dust, dirt and other foreign materials accumu­lated on the engine and surrounding parts thoroughly.
Such materials can cause fire or the engine to over­heat. In particular, clean the top surface of the battery
thoroughly. Dust can cause a short-circuit.
Always operate the engine at a position at least 1 m
[3.28 ft.] away from buildings and other equipment to
prevent possible fire caused by engine heat.

Avoid accessing crankcase until engine
cools

Do not attempt to open the side cover of the crankcase
before the engine cools down. Wait at least 10 minutes
after stopping the engine.
Opening the cover when the engine is hot allows fresh
air to flow into the crankcase, which can cause oil mist
to ignite and explode.

Care about fuel, oil and exhaust gas leakage

If any fuel, oil or exhaust gas leakage is found, immedi­ately take corrective measures to stop it.
Such leakages, if left uncorrected, can cause fuel or
engine oil to reach hot engine surfaces or hot exhaust
gas to contact flammable materials, possibly leading to
personal injury and/or damage to equipment.

Use explosion-proof lighting apparatus

When inspecting fuel, engine oil, coolant, battery elec­trolyte, etc., use a flameproof light. An ordinary light, if
accidentally broken, may ignite and cause an explo­sion.

Prevent electrical wires from short-circuit­ing

Avoid inspecting or servicing the electrical system with
the ground cable connected to the battery. Otherwise,
a fire could result from short-circuiting. Be sure to dis­connect the battery cable from the negative (-) terminal
before beginning with the work procedure.
Short-circuits, possibly resulting in fire, may be caused
by a loose terminal or damaged cable/wire. Inspect the
terminals, cables and wires, and repair or replace the
faulty parts before beginning with the service proce­dure.

Keep fire extinguishers and first-aid kit
handy

Keep fire extinguishers handy, and
become familiar with their usage.
Keep a first-aid kit at the designated
place where it is easily accessible
by anyone at any time.
Establish response procedures to
follow in the event of fire or accident. Provide an emer­gency evacuation route, contact points, and means of
communication in case of emergency.

WARNING

INTRODUCTION

IV

Stay clear of all rotating and moving parts

Install protective covers on rotating parts

Make sure the protective covers for
engine rotating parts are properly
installed as intended. Repair loose
or damaged protective covers as
necessary.
Never remove the covers guarding
personnel from rotating parts, when the engine is oper­ating.
When combining the engine with the engine-driven ma­chine or radiator, always provide a cover on every ex­posed moving part such as driving belt and coupling.
Never remove protective covers.

Ensure safety of neighboring people before
starting engine

Before starting the engine, ensure that there is nobody
in the neighborhood and that no tools are left on or near
the engine. Verbally notify people around the engine or
in the work area when starting the engine.
When the starter device is posted with a sign that pro­hibits startup operation, do not operate the engine.

Stay clear of moving parts during engine
running

Do not approach rotating or sliding
parts of the engine when the engine
is in operation.
Keep objects likely to be caught by
rotating parts away from such parts.
If any part of the clothing or outfit­ting is caught by a rotating part, se­rious bodily injuries could result.

Lockout and tagout

Be sure to lockout and tagout before starting inspection
and maintenance.
Lockout and tagout are effective methods of cutting off
machines and equipment from energy sources.
To accomplish the lockout/tagout, remove the starter
switch key, set the battery switch to OFF and attach a
"Do Not Run" or similar caution tag to the starter switch.
The starter switch key must be kept by the person who
performs inspection and maintenance during the work.
In the case of pneumatic starting type, close the main
valve of the air tank and post a tag saying "Do Not
Open the Valve" or the like.

Keep engine stopped during servicing

Be sure to stop the engine before proceeding to inspec­tion and service procedure. Never attempt to make ad­justments on the engine parts while the engine is
running. Rotating parts such as belt can entangle your
body and cause serious injuries.

Always restore engine turning tools after
use

Do not forget to remove the tools which have been
used for turning the engine during inspection or servic­ing, after the procedure is finished. Remember also
that the turning gear must be returned to the operating
condition before starting the engine.
Starting the engine with the turning tools inserted or
with the turning gear in engagement can lead to not
only engine damage but also personal injuries.

WARNING

INTRODUCTION

V

Be careful of burns

Do not touch the engine during or immedi­ately after operation

Do not touch the engine during or
immediately after operation to
avoid risk of burns.
To conduct maintenance and in­spection work, wait until the engine
has cooled sufficiently, checking
the temperature gauge.

Slowly and carefully open radiator cap

Never attempt to open the radiator cap while the engine
is running or immediately after the engine stops. Give a
sufficient cooling time to the engine coolant before
opening the cap.
When opening the radiator cap, slowly turn the cap to
release internal pressure. To prevent scalds with steam
gushing out, wear thick rubber gloves or cover the cap
with a cloth.
Close the radiator cap tightly without fail.
The coolant is very hot and under pressure during en­gine running or just after the engine stops. If the radia­tor cap is not closed tightly, steam and hot coolant may
gush out and can cause scalds.

Add coolant only after the coolant tempera­ture dropped

Do not add coolant immediately after the engine stops.
Wait until the coolant temperature lowers sufficiently to
avoid a risk of burns.

Never remove heat shields

The exhaust system, which becomes extremely hot
while the engine is operating, is provided with various
heat shields. Do not remove these heat shields. If any
of these heat shields have been removed owing to un­avoidable circumstances during the work, be sure to re­store them after the work is completed.

Be careful of exhaust fume poi­soning

Operate engine in well-ventilated area

If the engine is installed in an en­closed area and the exhaust gas is
ducted outside, ensure that there is
no exhaust gas leak from duct
joints.
Take care that the exhaust gas is
not discharged toward plants or animals.
Exhaust gas from the engine contains carbon monox­ide and other harmful substances. Operating the en­gine in an ill-ventilated area can produce gas
poisoning.

Protect ears from noises

Wear ear plugs

Always wear ear plugs when enter­ing the machine room (engine
room). Combustion sound and me­chanical noise generated by the en­gine can cause hearing problems.

WARNING WARNING

WARNING

INTRODUCTION

VI

Be careful of falling down

Lift engine correctly

To lift the engine, always use a cor­rect wire rope capable of withstand­ing the engine weight.
Attach the wire rope to the lifting
hangers provided on the engine us­ing a correct sling.
During lifting process, keep the en­gine in a well-balanced position by taking the center of
gravity of the engine into consideration.
If the wire rope contacts the engine directly, place a
cloth or other soft padding to avoid damage to the en­gine and wire rope.

Do not climb onto the engine

Do not climb onto the engine, nor step on any engine
parts located on the lateral sides.
To work on parts located on the upper section of en­gine, use a ladder, stool, etc., that is firmly secured.
Climbing on the engine may not only damage engine
parts but also cause parts to fall off and result in per­sonal injuries.

Establish firm scaffold during work

When working on the upper part of
the engine and other hard-to­reach places, use a stable work
platform.
Standing on a decrepit stool or
parts box may result in personal
injury. Do not place any unnecessary objects on a work
platform.

Be careful of handling fuel, engine
oil and LLC

Use only specified fuel, engine oil and long­life coolant (LLC)

Use only the fuel, oil and LLC specified in the applica­ble operation manual, and handle them carefully.
Use of any other fuel, oil or LLC, or improper handling
may cause various engine problems and malfunctions.
Obtain the Material Safety Data Sheets (MSDS) issued
by the fuel, oil and LLC suppliers, and follow the direc­tions in the MSDSs for proper handling.

Handle LLC (long life coolant) carefully

When handling LLC, always wear rubber gloves and
protective face mask. If LLC or cooling water containing
LLC comes into contact with your skin or eyes, or if it is
swallowed, you would suffer from inflammation, irrita­tion or poisoning.
Should LLC be accidentally swallowed, induce vomit­ing immediately and seek medical attention. Should
LLC enter your eyes, flush them immediately with plen­ty of water and seek medical attention. If LLC splashes
onto your skin or clothing, wash it away immediately
with plenty of water.
Keep flames away from LLC. The LLC can catch
flames, causing a fire.
Coolant containing LLC is a hazardous material. Do not
dispose of it in unauthorized manner. Abide by the ap­plicable law and regulations when discarding drained
coolant.

Proper disposal of waste oil and coolant
(LLC)

Do not discharge waste engine oil or coolant into sew­erage, river, lake or other similar places. Such a way of
disposal is strictly prohibited by laws and regulations.
Dispose of waste oil, coolant and other environmentally
hazardous waste in accordance with the applicable law
and regulations, or consult a Mitsubishi dealer.

WARNING

CAUTION

INTRODUCTION

VII

Service battery

Handle the battery correctly

• Never use flames or allow sparks
to generate near the battery. The
battery releases flammable
hydrogen gas and oxygen gas.
Any flames or sparks in the vicin­ity could cause an explosion.

• Do not use the battery the fluid level of which is low­ered below the lower limit line. Sustained use of the
battery could result in an explosion.

• Do not short the battery terminals with a tool or other
metal object.

• When disconnecting battery cables, always remove
the cable from the negative (-) terminal first. When
reconnecting the cables, attach the cable to the posi­tive (+) terminal first.

• Charge the battery in a well-ventilated area, with all
filling hole plugs removed.

• Make sure the cable clamps are securely installed on
the battery terminals. A loose cable clamp can cause
sparks that may result in an explosion.

• Before servicing electrical components or conducting
electric welding, set the battery switch to the [Open/
OFF] position or disconnect the cable from the nega­tive (-) battery terminal to cut off the electrical cur­rent.

• Electrolyte (battery fluid) contains dilute sulfuric acid.
Careless handling of the battery can lead to the loss
of sight and/or skin burns. Also, keep the battery fluid
off the mouth.

• Wear protective goggles and rubber gloves when
working with the battery (when adding water, charg­ing, etc.).

• If electrolyte is spilled onto the skin or clothing,
immediately wash it away with lots of water. Use
soap to thoroughly clean.

• The battery fluid can cause blindness if splashing
into eyes. If it gets into eyes, immediately flush it
away with plenty of clean fresh water, and seek
immediate medical attention.

• If the battery fluid is accidentally swallowed, gargle
with plenty of water, then drink lots of water, and
seek immediate medical attention.

When abnormality occurs

Stop overheated engine after cooling run

Even if the engine comes to overheat, do not stop the
engine immediately. Abrupt stopping of an overheated
engine can cause the coolant temperature to rise, re­sulting in seized engine parts. If the engine comes to
overheat, run the engine at low idling speed (cooling
operation), and stop the engine after the coolant tem­perature lowers sufficiently.
Do not add coolant immediately after stopping the en­gine. Adding coolant to a hot engine can cause the cyl­inder heads to crack due to sudden change in
temperature. Add coolant little by little after the engine
cools down to room temperature.

Avoid immediate restart after abnormal stop

If the engine stops abnormally, do not restart the en­gine immediately. If the engine stops with an alarm,
check and remedy the cause of the problem before re­starting. Sustained use of the engine without any rem­edy could result in serious engine problems.

Avoid continuous engine operation with too
low oil pressure

If an abnormal engine oil pressure drop is indicated,
stop the engine immediately, and inspect the lubrica­tion system to locate the cause. Continuous engine op­eration with low oil pressure may cause bearings and
other parts to seize.

Stop the engine immediately if the fan belt
breaks

If the fan belt breaks, stop the engine immediately.
Continuous engine operation with the broken fan belt
could cause the engine to overheat and thereby the
coolant to boil into steam, which may gush out from the
reserve tank or radiator, and cause personal injuries.

CAUTION CAUTION

INTRODUCTION

VIII

Other cautions

Modification of engine prohibited

Unauthorized modification of the engine will void the
manufacturer’s warranty.
Modification of the engine may not only cause engine
damage but also produce personal injuries.

Never break the seals

To ensure proper engine operation, the fuel control link
is provided with seals that protect the fuel injection vol­ume and rotation speed settings against tampering. If
these seals are broken and the settings are changed,
proper operation of the engine will no longer be guar­anteed, and the following problems will be expected to
occur.

• Rapid wear of moving and rotating parts

• Engine troubles such as damage and seizure of
engine parts

• Increased consumption of fuel and lubricating oil

• Deterioration of engine performance due to poorly
balanced fuel injection volume and governor opera­tion

Pre-operational check and periodic inspec­tion/maintenance

Be sure to perform the pre-operational checks and pe­riodic inspection/maintenance as described in this
manual.
Neglecting the pre-operational check or periodic in­spection/maintenance can arouse various engine trou­bles such as damage to parts, eventually leading to
serious accidents.

Break-in operation

A new engine needs to be broken in for the first 50
hours of operation. During this period, do not subject
the engine to heavy loads.
Operating a new engine under high loads or severe
conditions during the break-in period can shorten the
service life of the engine.

Warming-up operation

After starting the engine, run the engine at low idling
speeds for 5 to 10 minutes for warming-up. Start the
work after this operation is completed.
Warm-up operation circulates the lubricant through the
engine. Therefore, individual engine parts are well lu­bricated before they are subjected to heavy loads. This
is very important for longer service life, high-perfor­mance and economical operation.
Do not conduct warm-up operation for a longer time
than necessary. Prolonged warm-up operation causes
carbon build-up in the cylinders that leads to incom­plete combustion.

Avoid engine operations in a overload con­dition

If the engine is considered to be in an overloaded con­dition which is identified by too much black smoke, etc.,
immediately reduce the load on the engine such that
the correct output and load conditions may be
achieved.
Overloading the engine causes not only high fuel con­sumption but also excessive carbon deposits inside the
engine. Excessive carbon deposits can cause various
engine problems and shorten the service life of the en­gine remarkably.

Cooling operation before stopping engine

Always conduct the cooling operation (low speed
idling) for 5 to 6 minutes before stopping the engine.
Abruptly stopping the engine immediately after high­load operation can cause partial overheating and short­en the service life of the engine.
During cooling operation, check the engine for abnor­malities.

Protection of engine against water entry

Do not allow rainwater, etc. to enter the engine through
the air inlet or exhaust openings.
Do not wash the engine while it is operating. Cleaning
fluid (water) can be sucked into the engine.
Starting the engine with water inside the combustion
chambers can cause the water hammer action which
may result in internal engine damage and serious acci­dents.

CAUTION

INTRODUCTION

IX

Maintenance of air cleaner or pre-cleaner

The major cause of abnormal wear on engine parts is
dust entering with intake air. Worn parts produce many
problems such as an increase of oil consumption, de­crease of output, and starting difficulties. For effective
removal of dust from intake air, conduct maintenance
of the air cleaner according to the following instruc­tions.

• Do not conduct maintenance of the air cleaner/pre­cleaner while the engine is operating. Engine opera­tion without the air cleaner/precleaner in place allows
foreign matters to enter the turbocharger, causing it
to damage seriously.

• Remove the air cleaner/pre-cleaner slowly to prevent
dust accumulated on the element from falling off.
After removing the air cleaner or pre-cleaner, imme­diately cover the opening (inlet port in case of air
cleaner; port in body in case of pre-cleaner) with
plastic sheet or similar means to prevent dust from
entering the engine.

• Air cleaners equipped with a dust indicator will issue
an alarm if the element gets clogged. Service the
cleaner as soon as possible if an alarm is issued.

Observe safety rules at work site

Observe the safety rules established at your workplace
when operating and maintaining the engine.
Do not operate the engine if you are feeling ill.
Operation of the engine with reduced awareness may
cause improper operation that could result in accidents.
In such a case, inform your supervisor of your condi­tion.
When working in a team of two or more people, use
specified hand signals to communicate among work­ers.

Work clothing and protective gear

Wear a hardhat, face shield, safety shoes, dust mask,
gloves and other protective gear as needed.
When handling compressed air, wear safety goggles,
hardhat, gloves and other necessary protective gear.
Works without wearing proper protective gear could re­sult in serious injuries.

Use of tools optimum for each work

Always keep in mind to select most appropriate tools
for the work to be performed and use them correctly. If
tools are damaged, replace with new tools.

Avoidance of prolonged time of starter oper­ation

Do not operate the starter for more than 10 seconds at
a time even if the engine does not start. Wait for at least
30 seconds before next engine cranking.
Continuous operation of the starter will drain the battery
power and cause the starter to seize.

Do not turn off battery switch during opera­tion

If the battery switch is turned OFF when the engine is
running, not only various meters will stop working but
also the alternator may have its diode and transistor
deteriorated.

Cautionary instructions for transporting en­gine

When transporting the engine on a truck, consider the
engine weight, width and height to ensure safety. Abide
by road traffic law, road vehicles act, vehicle restriction
ordinance and other pertinent laws.

Avoid continuous engine operation in a low
load condition

Do not operate the engine continuously for more than
10 minutes at a load of less than 30%. Engine opera­tion in a low load condition increases the emission of
unburned fuel. Therefore, a prolonged time of engine
operation in a low load condition increases the quantity
of unburned fuel adhering to engine parts, provoking
the possibility of engine malfunctioning and shortening
the service life of the engine.

Ventilation of engine room

Always keep the engine room well ventilated. Insuffi­cient amount of intake air causes the operating temper­ature to rise, resulting in poor output and lowered
performance.
It is highly recommended to calculate the required
amount of air supply to the engine and install an ade­quate ventilation system before installing the engine.

Avoid contact with high-pressured fuel

Should fuel leak from a fuel injection pipe, do not touch
the spouting fuel directly.
Fuel in the fuel injection pipes is under high pressure. If
high-pressured fuel contacts you skin, it penetrates
through the skin and may result in gangrene.

INTRODUCTION

X

About warning labels

Maintenance of warning labels

Make sure all warning/caution labels are legible.
Clean or replace the warning/caution labels when the description and/or illustration are not clear to read.
For cleaning the warning/caution labels, use a cloth, water and soap. Do not use cleaning solvents, gasoline or other
chemicals to prevent the letters from getting blurred or the adhesion from being weakened.
Replace damaged or fractured labels with new ones.
If any engine part on which a warning label is attached is replaced with a new one, attach a new identical warning
label to the new part.

Warning labels

CAUTION

GENERAL CONTENTS

Group Name Contents Group No.

General

External view
System flow diagrams
Engine serial number location
Main specifications
Tips on disassembling and reassembling

1

Service data

Maintenance service data
Tightening torque table
Regarding submission of parts for EPA exhaust gas regulation

2

Service tools Special tool 3

Determination of overhaul

Determining overhaul timing
Testing compression pressure

4

Disassembly of basic engine

Disassembling and inspecting cylinder head and valve mechanism
Disassembling and inspecting flywheel
Disassembling and inspecting damper, gear case, timing gear and camshaft
Disassembling and inspecting piston, connecting rod, crankshaft and crankcase

5

Inspection and repair of basic
engine

Inspecting and repairing cylinder head and valve mechanism
Inspecting and repairing flywheel
Inspecting and repairing timing gear and camshaft
Inspecting and repairing piston, connecting rod, crankshaft and crankcase

6

Reassembly of basic engine

Reassembling piston, connecting rod, crankshaft and crankcase
Reassembling timing gear and camshaft
Reassembling flywheel
Reassembling cylinder head and valve mechanism

7

Fuel system

Removing fuel system
Disassembling, inspecting and reassembling fuel system
Installing fuel system

8

Lubrication system

Removing lubrication system
Disassembling, inspecting and reassembling lubrication system
Installing lubrication system

9

Cooling system

Removing cooling system
Disassembling, inspecting and reassembling cooling system
Installing cooling system

10

Inlet and exhaust systems

Removing turbocharger, inlet and exhaust systems
Disassembling, inspecting and reassembling inlet and exhaust systems
Installing turbocharger, inlet and exhaust systems

11

Electrical system

Removing electrical system
Disassembling, inspecting and reassembling electrical system
Installing electrical system

12

Adjustment and operation

Adjusting engine
Break-in operation
Performance test (JIS standard)

13

1-1

GENERAL

1. External view...................................1-2

2. System flow diagrams.....................1-4

2.1 Fuel system - flow diagram...................... 1-4

2.2 Lubrication system - flow diagram .... ... ... . 1-4

2.3 Cooling system - flow diagram................. 1 -5

2.4 Inlet and exhaust system - flow diagram.. 1-5

3. Engine serial number location.........1-6

4. Main specifications..........................1-7

5. Tips on disassembling and

reassembling.................................1-10

5.1 Disassembling........................................ 1-10

5.2 Reassembling........................................ 1-10

GENERAL

1-2

1. External view

Engine left view

Engine right view

Front

Rear

Fuei injection pump

Oil filter

Flywheel

Fuel filter

Oil drain plug

Relief valve

Magnet valve
(Stop solenoid)

Coolant drain plug

Water pump
(Coolant inlet)

Oil cooler

S6S-Y3T61HF

Front

Rear

Hanger

Oil pan

V-belt

Alternator

Thermostat case

Coolant outlet

Hanger

Oil filler

Turbocharger
(Exhaust outlet)

Starter

Oil filler

Air inlet

Damper

Rear plate

Oil level gauge

S6S-Y3T61HF

Side PTO
(Drive gear)

GENERAL

1-3

Engine left view

Engine right view

Front

Rear

Fuei injection pump

Oil filter

Flywheel

Oil drain plug

Oil level gauge

Relief valve

Magnet valve
(Stop solenoid)

Coolant drain plug

Water pump
(Coolant inlet)

Fuel filter

Oil cooler

S6S-Y3T62HF

FrontRear

Hanger

Oil pan

V-belt

Alternator

Thermostat case

Coolant outlet

Hanger

Oil filler

Turbocharger
(Exhaust outlet)

Starter

Oil filler

Air inlet

Damper

Rear plate

S6S-Y3T62HF

GENERAL

1-4

2. System flow diagrams

2.1 Fuel system - flow diagram

Fuel system - flow diagram

2.2 Lubrication system - flow diagram

Lubrication system - flow diagram

Fuel filter

Fuel inlet

Fuel leak-off pipe

Fuel injection nozzle

Fuel injection pump

Fuel return pipe

Fuel outlet

Oil jet

Pushrod

Tappet

Camshaft

Idler gear

Oil pump

Piston

Valve mechanism

Relief valve

Oil filter

Oil strainer

Oil pan

Main gallery

Crankshaft

Turbocharger

Oil cooler

Safety valve

Side PTO
(Drive gear)
[S6S-Y3T61HF]

GENERAL

1-5

2.3 Cooling system - flow diagram

Cooling system - flow diagram

2.4 Inlet and exhaust system - flow diagram

Inlet and exhaust system - flow diagram

Thermostat

Water pump

Water jacket

Cylinder head

Bypass hose

Cooling inlet

Cooling outlet

Oil cooler

Inlet

Inlet

Exhaust

Exhaust

Turbocharger

Exhaust manifold

Inlet manifold

Blow-by gas

Discharge

GENERAL

1-6

3. Engine serial number location

The engine serial number is stamped on the right side of
cylinder block.

Engine serial number location

Engine
serial number

GENERAL

1-7

4. Main specifications

Table 1-1 Main specifications (1 / 3)

Engine model S6S-Y3T61HF S6S-Y3T62HF

Main
specification

Type Water cooled, 4 cycle diesel engine, turbocharged
No. of cylinders - arrangement 6 cylinder in-line
Combustion system Swirl chamber type
Valve mechanism Overhead
Cylinder bore × stroke 94 × 120 mm [3.70 × 4.72 in.]
Displacement 4.996 L [305 cu. in.]
Compression ratio 22.0 : 1

Fuel

ASTM diesel fuel oil No.2-D

(JIS K2204 gas oil specification No.2 or 3)
Firing order 1 - 5 - 3 - 6 - 2 - 4
Direction of rotation Counterclockwise when viewed from flywheel side

Dimensions
(varies depending on
the specifications)

Length 999 mm [39.33 in.] 908 mm [35.75 in.]
Width 617 mm [24.29 in.] 622 mm [24.49 in.]
Height 854 mm [33.62 in.] 839 mm [33.03 in.]

Dry weight 350 kg [771.6 lb]

Basic engine

Cylinder Type Dry (integral with cylinder block)

Piston ring Number of rings

Compression rings: 2

Oil ring (w/expander): 1

Valve timing
(when warm)

Inlet valve

Open BTDC 18°
Close ABDC 54°

Exhaust valve

Open BBDC 66°

Close ATDC 22°
Starting system Electric
Starting aid system Glow plug

Side PTO

Allowable torque 98 N·m {10 kgf·m} [72 lbf·ft] ­Gear ratio 1 : 1 -

Fuel system

Fuel injection pump

Type Distribution (Bosch VE type)
Plunger diameter ø 11 mm [0.43 in.]
Cam lift 1.741 mm [0.0685 in.]
Governor Bosch, all speed type

Fuel injection nozzle

Nozzle type Denso, throttle type
Number of spray holes 1
Spray hole diameter ø 1.0 mm [0.039 in.]
Spray angle 0°
Valve opening pressure 11.77 MPa {120 kgf/cm²} [1706.80 psi]

Fuel filter Type Cartridge type paper element

GENERAL

1-8

Lubrication
system

Lubricating method

Forced circulation type

(pressure feed by oil pump)

Engine oil

Standard Class CF-4 oil SAE No.30 (API service classification)

Engine oil capacity

Engine total: approx. 16.5 L [4.36 U.S. gal.]

(approx. 15.5 L [4.10 U.S. gal.] in oil pan)

Oil pump

Type Trochoid
Speed ratio to crankshaft 0.74

Discharge capacity

38.7 L [10.22 U.S. gal.]/min

(at pump rotation of 2230 min

-1

,

0.3 MPa {3 kgf/cm²} [42.67 psi])

Relief valve

Type Piston valve type

Valve opening pressure

0.35 ± 0.05 MPa {3.5 ± 0.5 kgf/cm²}
[49.78 ± 7.11 psi]

Safety valve Opening pressure 1.1 MPa {11 kgf/cm²} [157 psi]
Oil cooler Type Plate type
Oil filter Type Cartridge type paper element

Cooling system

Cooling method Water-cooled, forced circulation
Coolant capacity (engine) 8 L [2.11 U.S. gal.]

Water pu mp

Type Volute type centrifugal pump
Speed ratio to crankshaft 1.05

Discharge capacity

160 L [42.27 U.S. gal.]/min

(at pump rotation of 3600 min

-1

,

0.075 MPa {0.75 kgf/cm²} [10.67 psi])

Cooling fan

Type Pressure type
Diameter ø 500 mm [19.69 in.]

Thermostat

Type Wax type
Valve opening temperature 76.5 ± 2°C [169.7 ± 3.6°F] (90°C [194.0°F] when fully opened)

Inlet and exhaust
system

Turbocharger

Model number TD06H
Qty 1

Table 1-1 Main specifications (2 / 3)

Engine model S6S-Y3T61HF S6S-Y3T62HF

GENERAL

1-9

Electrical
system

Voltage - polarity 24V - negative (-) ground

Starter

Model number M008T60373
Pinion meshing type Pinion shift
Output 24 V - 5 kW
Qty 1
Ring gear and pinion ratio 10/122

Alternator

Type 3-phase alternating current, with rectifier
Output 24 V - 35 A
Speed in use

to 8000 min

-1

Rated generating speed

5000 min

-1

Permissible speed

10000 min

-1

Speed ratio to crankshaft 1.85

Glow plug

Type Electric
Rated voltage - current 22 V - 4.4 A (15-second duration)

Magnetic valve
(Stop solenoid)

Rated voltage 24 V
Power consumption 14 W
Starting voltage 13 V or below
Return voltage 5 V or more
Coil resistance

37 Ω

Table 1-1 Main specifications (3 / 3)

Engine model S6S-Y3T61HF S6S-Y3T62HF

GENERAL

1-10

5. Tips on disassembling and reassem­bling

This service manual specifies the recommended procedures
to be followed when servicing Mitsubishi engines. The
manual also specifies the special tools that are required for
the work, and the basic safety precautions to follow when
working.
Note that this manual does not exhaustively cover potential
hazards that could occur during maintenance, inspection and
service work of engine.
When working on an engine, follow the relevant directions
given in this manual and observe the following instructions:

5.1 Disassembling

(1)

Use correct tools and instruments. Serious injury or
damage to the engine will result from using the wrong
tools and instruments.

(2) Use a n overhaul stand or work bench if necessary, and

follow the disassembling procedures described in this
manual.

(3) Ke ep the engine parts in order of removal to prevent

losing them.

(4) Pay atte ntion to assembling marks. Put your marks on

the parts, if necessary, to ensure correct reassembling.

(5) Carefully check each part for defects during

disassembling or cleaning. Do not miss symptoms
which can not be detected after disassembling or
cleaning.

(6) Wh en lifting or carrying heavy parts, exercise utmost

caution to ensure safety. Pay attention to balance of
heavy parts when handling. (Get help, and use jacks,
chain blocks and guide bolts as necessary.)

5.2 Reassembling

(1)

Wash all engine parts, except such parts as oil seals, O­rings and rubber sheets, in cleaning oil and dry them
with compressed air.

(2) Use correct tools and instruments.
(3) Use only high-quality lubricating oils and greases of

appropriate types. Be sure to apply oil, grease or
adhesive to the part wherever specified.

(4) Use a torque wrench to tighten parts correctly when

their tightening torques are specified.
Refer to "Tightening torque table."

(5) Replace all gaskets and packings with new ones unless

specified otherwise. Apply adhesive if necessary. Use
only the proper amount of adhesive.

2-1

SERVICE DATA

1. Maintenance service data ...............2-2

1.1 General.................................................... 2-2

1.2 Basic engine ............................................ 2-3

1.3 Fuel system.............................................. 2-6

1.4 Lubrication system............ ... ... ... .... .......... 2-6

1.5 Cooling system . ... ... ... ... ........................... 2-7

1.6 Inlet and exhaust system......................... 2-7

1.7 Electrical system...................................... 2-8

2. Tightening torque table ...................2-9

2.1 Major bolt tightening torque ..................... 2-9

2.1.1 Basic engine...............................................2-9

2.1.2 Fuel system................................................2-9

2.1.3 Lubrication system ...................................2-10

2.1.4 Cooling system.........................................2-10

2.1.5 Inlet and exhaust systems........................2-10

2.1.6 Electrical system ......................................2-10

2.2 Standard bolt and nut tightening torque. 2-11

2.2.1 Metric automobile screw thread ...............2-11

2.2.2 Metric course screw thread......................2-11

2.3 Standard stud tightening torque . .... ... ... .. 2-11

3. Regarding submission of parts for

EPA exhaust gas regulation..........2-12

SERVICE DATA

2-2

1. Maintenance service data

1.1 General

Table 2-1 Maintenance service data table - General Unit: mm [in.]

Inspection point Nominal Standard Limit Remark

Maximum rotation speed (No-load)

2570 ± 50 min

-1

Minimum rotation speed (No-load)

820 ± 25 min

-1

Compression pressure (at 300 min-1)

3.2 MPa

{33 kgf/cm²}

[469 psi] or more

2.8 MPa

{29 kgf/cm²}

[412 psi] or less

When oil and water
temperatures
at 20 to 30°C
[68 to 86°F]

Lubricating
oil pressure

Rotated speed
at 1500 min

-1

0.3 to 0.5 MPa

{3 to 5 kgf/cm²}

[43 to 71 psi]

0.15 MPa

{1.5 kgf/cm²}

[21 psi] or less

Oil temperature
at 60 to 70°C
[140 to 158°F]

Idling speed

0.10 MPa

{1.0 kgf/cm²}

[14 psi] or more

0.05 MPa

{0.5 kgf/cm²}

[7 psi] or less

Valve timing

Inlet open BTDC 18°

Values are only for
checking valve timing
and are different from
the actual ones.

Inlet closes ABDC 54°
Exhaust open BBDC 66°
Exhaust closes ATDC 22°

Valve clearance

Inlet 0.25 [0.0098]

When engine is cold

Exhaust 0.25 [0.0098]

Fuel injection timing (before TDC) 5°

SERVICE DATA

2-3

1.2 Basic engine

Table 2-2 Maintenance service data table - Basic engine (1 / 4) Unit: mm [in.]

Inspection point Nominal Standard Limit Remark

Rocker

Rocker bushing inside diameter

ø 19

[0.75]

19.010 to 19.030

[0.7484 to 0.7492]

Rocker shaft outside diameter

ø 19

[0.75]

18.980 to 19.000

[0.7472 to 0.7480]

Clearance between rocker bushing and
shaft

0.010 to 0.050

[0.0004 to 0.0020]

0.070

[0.0028]

Valve and
valve guide

Valve s te m
outside diameter

Inlet

ø 8

[0.31]

7.940 to 7.955

[0.3126 to 0.3132]

7.900

[0.3110]

Exhaust

ø 8

[0.31]

7.920 to 7.940

[0.3118 to 0.3126]

7.850

[0.3091]

Clearance between
valve stem and
guide

Inlet

0.065 to 0.095

[0.0026 to 0.0037]

0.150

[0.0059]

Exhaust

0.080 to 0.115

[0.0031 to 0.0045]

0.200

[0.0079]

Valve guide mounting dimension

14

[0.55]

13.9 to 14.1

[0.547 to 0.555]

Valve seat

Valve seat angle 30°

Valve sinkage

Inlet

0.4

[0.016]

0.3 to 0.5

[0.012 to 0.020]

1.0

[0.039]

Exhaust

0.5

[0.020]

0.4 to 0.6

[0.016 to 0.024]

1.0

[0.039]

Seat width

1.4

[0.055]

1.26 to 1.54

[0.0496 to 0.0606]

1.8

[0.071]

Valve margin

2.13

[0.0839]

Refacing

permissible up to

1.83 [0.0720]

Valve
spring

Free length

48.85

[1.9232]

47.60

[1.8740]

Perpendicularity

A = 1.5°or less

B = 1.3 [0.051]

or less

Lf = 48.85 [1.9232]

B = 1.5 [0.059]

at the end

Set length/set load

43 mm [1.69 in.]/

176 to 196 N

{18 to 20 kgf}

[39 to 44 lbf]

43 mm [1.69 in.]/

147 N

{15 kgf}

[33 lbf]

Pushrod Runout

0.6

[0.024] or less

0.6

[0.024]

Runout (dial gaule reading)
when push rod is supported
along center line of spheri­cal surface at either end.

Cylinder head

Distortion of bottom face

0.05

[0.0020] or less

0.20

[0.0079]

Reface minimum thickness.

Compressed thickness of gasket

1.2

[0.047]

1.20 ± 0.05

[0.0472 ± 0.0020]

Cylinder

Inside diameter

ø 94

[3.70]

94.000 to 94.035

[3.7008 to 3.7022]

Repair limit:

94.200 [3.7087]
Replace limit:

94.700 [3.7283]

Refinish cylinder to 0.25
[0.0098] or 0.50 [0.0197]
oversize of nominal valve
by honing.
Use oversize piston and pis­ton ring.

Circularity

0.01

[0.0004] or less

Cylindricality

0.015

[0.0006] or less

Valve
margin

Val ve
sinkage

Val ve
seat angle

Seat width

A

B

Lf

SERVICE DATA

2-4

Piston

Outside diameter
(at piston skirt)

STD

ø 94

[3.70]

93.955 to 93.985

[3.6990 to 3.7002]

93.770

[3.6917]

0.25 [0.0098]/OS

94.205 to 94.235

[3.7089 to 3.7100]

94.020

[3.7016]

0.50 [0.0197]/OS

94.455 to 94.485

[3.7187 to 3.7199]

94.270

[3.7114]

Protrusion from crankcase

-0.25 to 0.15

[-0.0098 to 0.0059]

Bearing clearance check.

Weight difference in one engine

5 g

[0.2 oz.] or less

Piston ring

Clearance between
piston ring groove

No.1
compression ring

2.5 [0.098]

0.07 to 0.11

[0.0028 to 0.0043]

0.200

[0.0079]

Use the piston with replac­ing
the piston rings until reach­ing
the limits.
when reaching the limits,
replace the piston.

No.2
compression ring

2.0 [0.079]

0.045 to 0.085

[0.0018 to 0.0033]

0.150

[0.0059]

Oil ring 4.0 [0.157]

0.020 to 0.060

[0.0008 to 0.0024]

0.150

[0.0059]

Closed gap of ring

No.1
compression ring

0.30 to 0.50

[0.0118 to 0.0197]

1.50

[0.0591]

No.2
compression ring

0.50 to 0.70

[0.0197 to 0.0276]

1.50

[0.0591]

Oil ring

0.30 to 0.50

[0.0118 to 0.0197]

1.50

[0.0591]

Piston pin

Outside diameter

ø 30

[1.18]

29.994 to 30.000

[1.1809 to 1.1811]

Clearance between piston pin

0.000 to 0.016

[0.0000 to 0.0006]

0.050

[0.0020]

Clearance between connecting rod bushing

0.020 to 0.091

[0.0008 to 0.0036]

0.120

[0.0047]

Connecting
rod

Bushing inside diameter

ø 30

[1.18]

30.020 to 30.045

[1.1819 to 1.1829]

Bend and twist

0.05/100

[0.0020/3.94]

or less

0.15

[0.0059]

Clearance between crankpin and connect­ing rod bearing (oil clearance)

0.030 to 0.090

[0.0012 to 0.0035]

0.200

[0.0079]

Use connecting rod with
replacing bearing until
reaching the limit.
when exceeding the limit,
re-gring the crankpin and
replace the bearing with
under size.

End play 33 [1.30]

0.15 to 0.35

[0.0059 to 0.0138]

0.50

[0.0197]

Replace connecting rod.

Weight dif ference of connecting rod assem­bly in one engine

10 g

[0.35 oz.] or less

Flywheel

Flatness

0.15

[0.0059] or less

0.50

[0.0197]

Runout

0.15

[0.0059] or less

0.50

[0.0197]

Damper

Perpendicularity runout

0.5

[0.020] or less

1.5

[0.059]

Replace with a new one
after operating 8000 hours.

Periphery runout

0.5

[0.020] or less

1.5

[0.059]

Table 2-2 Maintenance service data table - Basic engine (2 / 4) Unit: mm [in.]

Inspection point Nominal Standard Limit Remark

SERVICE DATA

2-5

Camshaft

Runout

0.04

[0.0016] or less

0.10

[0.0039]

TIR

Cam lift

Inlet

6.682

[0.2631]

6.382 to 6.782

[0.2513 to 0.2670]

6.182

[0.2434]

Exhaust

6.722

[0.2646]

6.422 to 6.822

[0.2528 to 0.2686]

6.222

[0.2450]

Journal outside
diameter

No. 1, 2, 3

ø 54

[2.13]

53.94 to 53.96

[2.1236 to 2.1244]

53.90

[2.1220]

No.4

ø 53

[2.09]

52.94 to 52.96

[2.0842 to 2.0850]

52.90

[2.0827]

Clearance between camshaft journal and
camshaft bushing

0.07 to 0.11

[0.0028 to 0.0043]

0.15

[0.0059]

Replace bushing if limit is
exceeded.
Reaming if necessary.

End play

5

[0.20]

0.10 to 0.25

[0.0039 to 0.0098]

0.30

[0.0118]

Replace thrust plate.

Idler

Clearance between bushing and shaft

0.009 to 0.050

[0.0004 to 0.0020]

0.100

[0.0039]

Idler gear end play

30

[1.18]

0.05 to 0.20

[0.0020 to 0.0079]

0.35

[0.0138]

Replace thrust plate.

Interference between shaft and crankcase
hole

ø 35

[1.38]

0.035T to 0.076T

[0.0014 to 0.0030]

Timing gear backlash

0.05 to 0.15

[0.0020 to 0.0059]

0.25

[0.0098]

Replace gear.

Crankshaft

Crank journal outside diameter

ø 78

[3.07]

77.955 to 77.970

[3.0691 to 3.0697]

77.850 [3.0650]

(Repair)

77.100 [3.0354]

(Replace)

Crankpin outside diameter

ø 58

[2.28]

57.955 to 57.970

[2.2817 to 2.2823]

57.800

[2.2756]

Distance between centers of journal and
crankpin

60

[2.36]

59.96 to 60.04

[2.3606 to 2.3638]

Parallelism between journal and crankpin

Pin maximum

defection:

0.01

[0.0004] or less

Roundness of journals and crankpins

0.01

[0.0004] or less

0.03

[0.0012]

Cylindericity of journals and crankpins

0.01

[0.0004] or less

0.03

[0.0012]

Fillet radius of pin and journal

R3

[0.12]

2.8 to 3.2

[0.110 to 0.126]

Runout (TIR)

0.04

[0.0016] or less

0.10

[0.0039]

TIR

End play

31

[1.22]

0.100 to 0.264

[0.0039 to 0.0104]

0.300

[0.0118]

Replace thrust plates before
limit is reached. If limit is
exceeded, use one of follow­ing oversize thrust plates;
+0.25 [+0.0098], +0.50
[+0.0197], +0.75 [+0.0295]

Table 2-2 Maintenance service data table - Basic engine (3 / 4) Unit: mm [in.]

Inspection point Nominal Standard Limit Remark

D1

D2

SERVICE DATA

2-6

1.3 Fuel system

1.4 Lubrication system

Main bearing

Clearance between main bearing and crank­shaft journal

0.050 to 0.110

[0.0020 to 0.0043]

0.200

[0.0079]

crank journal

outside diameter

(ø 78 [3.0709])

-0.9 [-0.0354]

Replace bearings before
limit is reached. Regrind
crank journal and use next
undersize bearings if limit is
exceeded;

-0.25 [-0.0098], -0.50
[-0.0197], -0.75 [-0.0295]

Crankcase

Flatness of top surface

0.05

[0.0020] or less

0.20

[0.0079]

Reface minimum thickness.

Tappet guide hole inside diameter

14.000 to 14.018

[0.5512 to 0.5519]

14.100

[0.5551]

Clearance between tappet and tappet guide
hole

0.016 to 0.052

[0.0006 to 0.0020]

0.08

[0.0031]

If the diameter is the limit or
more, replace tappet.

Table 2-2 Maintenance service data table - Basic engine (4 / 4) Unit: mm [in.]

Inspection point Nominal Standard Limit Remark

Table 2-3 Maintenance service data table - Fuel system Unit: mm [in.]

Inspection point Nominal Standard Limit Remark

Fuel
injection
nozzle

Valve opening pres­sure

11.77 MPa

{120 kgf/cm²}

[1707 psi]

11.77 to 12.75 MPa

{120 to 130 kgf/cm²}

[1707 to 1849 psi]

Make shim adjustment.
Pressure varies by 1 MPa {10 kgf/cm²} [142
psi] per 0.1 [0.004] thickness of shim.

Spray cone angle 0°

Check nozzle with a hand tester (at fuel oil
temperature 20°C [68°F]). Replace the noz­zle tip if the spray pattern is still bad after
washing in clean fuel oil.

Nozzle valve seat oil
sealing

Seat shall hold a test pressure lower than
valve opening pressure by 2 MPa
{20 kgf/cm²} [285 psi] for 10 seconds.

Wash in clean fuel oil or replace nozzle tip.

Table 2-4 Maintenance service data table - Lubrication system Unit: mm [in.]

Inspection point Nominal Standard Limit Remark

Oil pump

Clearance between outer rotor and case

0.20 to 0.30

[0.0079 to 0.0118]

0.50

[0.0197]

Replace pump assembly.

Main shaft outside diameter
(between case)

ø 16

[0.63]

15.985 to 16.000

[0.6293 to 0.6299]

Main shaft outside diameter
(between oil pump bushing)

ø 14

[0.55]

13.957 to 13.975

[0.5495 to 0.5502]

Clearance between main shaft and pump
case

0.032 to 0.074

[0.0013 to 0.0029]

0.150

[0.0059]

Replace pump case or
replace pump assembly.

Clearance between main shaft and oil
pump bushing

0.025 to 0.111

[0.0010 to 0.0044]

0.200

[0.0079]

Replace oil pump bush­ing or replace pump
assembly.

Clearance between inner rotor and outer
rotor

0.13 to 0.15

[0.0051 to 0.0059]

0.20

[0.0079]

Replace outer rotor and
shaft assembly.

Rotor and case end play

0.04 to 0.09

[0.0016 to 0.0035]

0.15

[0.0059]

Replace pump assembly.

Relief valve Valve opening pressure

0.35 MPa

{3.6 kgf/cm²}

[51.20 psi]

0.35 ± 0.05 MPa

{3.5 ± 0.5 kgf/cm²}

[49.78 ± 7.11 psi]

Safety valve Valve opening pressure

1.1 MPa

{11 kgf/cm²}

[157 psi]

SERVICE DATA

2-7

1.5 Cooling system

1.6 Inlet and exhaust system

Table 2-5 Maintenance service data table - Cooling system Unit: mm [in.]

Inspection point Nominal Standard Limit Remark

Thermostat

Temperature at which valve starts
opening

76.5 ± 1.5°C

[170 ± 3.5°F]

Temperature at which valve lift is
9 [0.35], minimum

90 ± 1.5°C

[194 ± 2.7°F]

Table 2-6 Maintenance service data table - Inlet and exhaust system Unit: mm [in.]

Inspection point Nominal Standard Limit Remark

Distortion of exhaust manifold

0.2

[0.008] or less

Repair by grinding or replace.

Axial clearance of cartridge assembly

0.057 to 0.103

[0.0022 to 0.0041]

SERVICE DATA

2-8

1.7 Electrical system

Table 2-7 Maintenance service data table - Electrical system Unit: mm [in.]

Inspection point Nominal Standard Limit Remark

Starter

Commutator

Outside diameter

ø 32

[1.26]

31.4

[1.236]

Runout

0.05

[0.0020] or less

0.10

[0.0039]

Undercut depth

0.4 to 0.6

[0.016 to 0.024]

0.2

[0.008]

Brush length

18

[0.71]

11

[0.43]

Tension of brush springs

34 N

{3.5 kgf}

[7.7 lbf]

29.4 to 39.4 N

{3.0 to 4.0 kgf}

[6.6 to 8.8 lbf]

13.7 N

{1.4 kgf}

[3.1 lbf]

No-load char­acteristics

Voltage 23 V
Armature current 85 A or less
Rotational speed

3300 min

-1

or more

Load charac­teristics

Voltage 9 V
Armature current 1400 A or less

Torque

88.26 N·m

{9.0 kgf·m}

{65 lbf·ft} or more

Alternator

Regulator adjusting voltage
(alternator 5000 min

-1

, load at 5 A or lower)

28.5 × 0.5 V

Resistance between slip rings

9.0 to 10.4 Ω

at 20°C [68°F]

Brush spring tension

5.8 to 7.0 N

{590 to 710 gf}

[1.3 to 1.6 lbf]

3.2 N

{330 gf}

[0.7 lbf]

Brush length 21.5 [0.85] 8 [0.31]

Glow plug

Rated voltage DC22 V

(When applying the rated
voltage for 15 seconds.)

Armature current

4.4

-0.7

+0.3

A

Magnetic
valve

Resistance value

37 to 41 Ω

Ambient temperature:
23 ± 5°C
[73.4 ± 9°F])

V-belt Deflection

8

[0.31]

When center of belt pressed
at approx.
98 N {10 kgf} [22 lbf]

SERVICE DATA

2-9

2. Tightening torque table

2.1 Major bolt tightening torque

2.1.1 Basic engine

Note: When [Wet] is indicated, apply engine oil to the threads and bearing surfaces of the bolts and nuts.

2.1.2 Fuel system

Table 2-8 Tightening torque table - Basic engine

Description

Threads

Dia × Pitch

(mm)

Torque

Remark

N·m kgf·m lbf·ft

Cylinder head 12 × 1.75 118 ± 5 12 ± 0.5 87 ± 3.6
Cylinder head plug 16 × 1.5 44.1 ± 5 4.5 ± 0.5 32.5 ± 3.6
Rocker cover 8 × 1.25 11.3 ± 1.5 1.15 ± 0.15 8.5 ± 1.1
Rocker shaft bracket (long) 8 × 1.25 17.5 ± 2.5 1.75 ± 0.25 12.7 ± 1.8
Main bearing cap 14 × 2.0 103 ± 5 10.5 ± 0.5 76 ± 3.6 [Wet]
Connecting rod cap 10 × 1.25 54 ± 5 5.5 ± 0.5 40 ± 3.6
Flywheel 12 × 1.25 83.4 ± 4.9 8.5 ± 0.5 61.5 ± 3.6
Camshaft thrust plate 8 × 1.25 11.5 ± 1.5 1.15 ± 0.15 8.3 ± 1.1
Front plate 8 × 1.25 11. 3 ± 1.5 1.15 ± 0.15 8.3 ± 1.1
Timing gear case cover 8 × 1.25 18.5 ± 1.5 1.85 ± 0.15 13.4 ± 1.1
Crankshaft pulley 30 × 1.5 490 ± 10 50 ± 1 362 ± 7.2
Idler thrust plate 10 × 1.25 34 ± 5 3.5 ± 0.5 25 ± 3.6
Rear plate 10 × 1.25 56 ± 5.9 5.7 ± 0.6 41.2 ± 4.3
Rocker adjusting nut 8 × 1.25 20 ± 2 2 ± 0.2 14.5 ± 1.4

Table 2-9 Tightening torque table - Fuel system

Description

Threads

Dia × Pitch

(mm)

Torque

Remark

N·m kgf·m lbf·ft

Fuel injection nozzle
(engine)

20 × 1.5 58.8 ± 5.9 6 ± 0.6 43.4 ± 4.3

Fuel injection nozzle retaining nut 16 × 0.75 36.8 ± 2.5 3.75 ± 0.25 27.1 ± 1.8
Fuel injection pump gear 12 × 1.75 63.7 ± 5 6.5 ± 0.5 47 ± 3.6
Fuel injection pump over flow valve - 17.5 ± 2.5 1.75 ± 0.25 12.7 ± 1.8
Fuel injection pipe nut 12 × 1.5 29.4 ± 2.9 3 ± 0.3 21.7 ± 2.2
Fuel return pipe nut 10 × 1.25 19.6 ± 1.9 2 ± 0.2 14.5 ± 1.4
Fuel filter drain plug 14 × 1.0 2 ± 0.5 0.2 ± 0.05 1.4 ± 0.4
Fuel filter cartridge 20 × 1.5 15 ± 3 1.5 ± 0.3 10.8 ± 2.2
Fuel filter water level sensor 36 × 1.5 5 ± 1 0.5 ± 0.1 3.6 ± 0.7
Fuel leak off pipe mounting nut 12 × 1.5 2 2.6 ± 1.9 2.3 ± 0.2 16.6 ± 1.4

SERVICE DATA

2-10

2.1.3 Lubrication system

2.1.4 Cooling system

2.1.5 Inlet and exhaust systems

2.1.6 Electrical system

Table 2-10 Tightening torque table - Lubrication system

Description

Threads

Dia × Pitch

(mm)

Torque

Remark

N·m kgf·m lbf·ft

Oil pan 8 × 1.25 11. 3 ± 1.5 1.15 ± 0.15 8.3 ± 1.1
Oil pan drain plug 20 × 1.5 78 ± 5 8 ± 0.5 57.9 ± 3.6
Oil pump gear 10 × 1.25 33 ± 5 3.4 ± 0.5 24.6 ± 3.6
Oil pressure relief valve 22 × 1.5 49 ± 4.9 5 ± 0.5 36.2 ± 3.6
Safety valve 18 × 2.0 69 ± 5 7 ± 0.5 50.6 ± 3.6

Table 2-11 Tightening torque table - Cooling system

Description

Threads

Dia × Pitch

(mm)

Torque

Remark

N·m kgf·m lbf·ft

Thermostat case 8 × 1.25 18.1 ± 1.5 1.85 ± 0.15 13.4 ± 1.1
Water drain plug 1/4-18NPTF 39.2 ± 3.9 4 ± 0.4 28.9 ± 2.9

Water pump mounting bolt

8 × 1.25 9.8 ± 1 1 ± 0.1 7.2 ± 0.7
8 × 1.25 18.1 ± 3.4 1.85 ± 0.35 13.4 ± 2.5

Water pump plug R3/8 32.4 ± 2 3.3 ± 0.2 23.9 ± 1.4

Table 2-12 Tightening torque table - Inlet and exhaust systems

Description

Threads

Dia × Pitch

(mm)

Torque

Remark

N·m kgf·m lbf·ft

Exhaust manifold 8 × 1.25 18.1 ± 3.4 1.85 ± 0.35 13.4 ± 2.5
Turbo oil feed eye bolt 10 × 1.25 16.2 ± 2.5 1.65 ± 0.25 11.9 ± 1.8
Clamp - 4 ± 0.5 0.41 ± 0.05 3.0 ± 0.37
Coupling assembly 6 × 1.0 8.3 ± 0.5 0.85 ± 0.05 6.1 ± 0.4

Table 2-13 Tightening torque table - Electrical system

Description

Threads

Dia × Pitch

(mm)

Torque

Remark

N·m kgf·m lbf·ft

Starter terminal B 8 × 1.25 10.8 ± 1 1.1 ± 0.1 8 ± 0.7
Alternator pulley 20 × 1.5 147 ± 15 15 ± 1.5 108.4 ± 11.1
Glow plug (Engine body) 10 × 1.25 17.5 ± 2.5 1.75 ± 0.25 12.7 ± 1.81
Glow plug (terminal) 4 × 0.7 1.25 ± 0.25 0.13 ± 0.03 0.94 ± 0.2
Magnetic valve assembly 24 × 1 20 ± 5 2 ± 0.5 15 ± 3.6

SERVICE DATA

2-11

2.2 Standard bolt and nut tightening torque

2.2.1 Metric automobile screw thread

2.2.2 Metric course screw thread

Note: (a) This table lists the tightening torque for standard bolts and nuts.

(b) The numerical values in the table are for fasteners with spring washers.

(c) The table shows the standard values with a maximum tolerance value of ±10%.

(d) Use the tightening torque in this table unless otherwise specified.

(e) Do not apply oil to threaded portions. (Dry)

2.3 Standard stud tightening torque

Table 2-14 Metric automobile screw thread

Threads

Dia × Pitch

(mm)

Width

across flats

(mm) [in.]

Strength classification

4T 7T 10.9

N·m kgf·m lbf·ft N·m kgf·m lbf·ft N·m kgf·m lbf·ft

M6 × 1.0 10 [0.39] 3.9 0.4 2.9 8.8 0.9 6.5 12.7 1.3 9.4

M8 × 1.25 12 [0.47] 11.8 1.2 8.7 18 1.9 13 30 3.1 22
M10 × 1.25 14 [0.55] 21.1 2.15 16 35 3.6 26 60 6.1 44
M12 × 1.25 17 [0.67] 35.3 3.6 26 64 6.5 47 108 11.0 80

4 7

10

Table 2-15 Metric course screw thread

Threads

Dia × Pitch

(mm)

Width

across flats

(mm) [in.]

Strength classification

7T 10.9

N·m kgf·m lbf·ft N·m kgf·m lbf·ft

M10 × 1.5 14 [0.55] 32 3.3 24 58 5.9 43
M12 × 1.75 17 [0.67] 57 5.8 42 102 10.4 75

Table 2-16 Standard stud tightening torque

Threads

Dia × Pitch

(mm)

For driving in aluminum materials For driving in ferrous materials

N·m kgf·m lbf·ft N·m kgf·m lbf·ft

M8 × 1.25 5.4 ± 0.5 0.55 ± 0.05 4.0 ± 0.4 13.7 ± 1.0 1.4 ± 0.1 10.1 ± 0.7

M10 × 1.25 12.7 ± 1.0 1.3 ± 0.1 9.4 ± 0.7 23.5 ± 2.0 2.4 ± 0.2 17.4 ± 1.4

SERVICE DATA

2-12

3. Regarding submission of parts for
EPA exhaust gas regulation

CAUTION

When replacing parts, be sure to use OEM designated
parts.
If OEM parts are not used, the exhaust emission's war­ranty be voided.
New parts may be updated due to improvement.
Fuel and exhaust system repairs should only be con­ducted by an authorized Mitsubishi forklift truck dealer.
Tampering or adjusting the fuel system components
will void the warranty and could be in violation of the
EPA regulations.
The fuel injection pump is an emission control device.
Components inside the pump are specifically cali­brated to meet the engine emissions requirements and
should never be disassembled or rebuilt.
If the pump fails to operate, replace the assembly with
an OEM replace part.

The following parts have been submitted in accordance with
EPA emission regulation.

(1) Fuel injection assembly
(2) Fuel injection nozzle
(3) Turbocharger assembly
(4) Other related parts (including designated fuel and

lubricant)

3-1

SERVICE TOOLS

1. Special tool......................................3-2

SERVICE TOOLS

3-2

1. Special tool

Table 3-1 Special tool list (1 / 3)

Tool name Part No. Shape Use

Compression gauge 33391-02100

Engine compression pressure
measuring
0 to 7 MPa {0 to 71.4 kgf/cm²}
[0 to 1015.54 psi]

Gauge adapter 30691-21100

Engine compression pressure
measuring

Socket 58309-73100 Engine turning

Valve spring pusher 30691-04500

Valve spr ing
removal/installation

Valve guide remover 32A91-00300 Valve guide removal

Valve sheet insert
caulking tool

Inlet: 36791-00200
Exhaust:
34491-03020

Valve seat installation

Stem seal installer 32A91-10200 Stem seal installation

SERVICE TOOLS

3-3

Socket 34491-00300

Camshaft, thrust plate and
rocker bracket installation

Valve guide installer 32A91-00100 Valve guide installation

Camshaft bushing installer set 30691-00010

Camshaft bushing
removal/installation

Idler bushing installer 30091-07300

Idler bushing
removal/installation

Idler shaft puller MH061077 Idler shaft removal

Piston ring pliers 31391-12900 Piston ring removal/installation

Connecting rod bushing puller 32A91-00500

Connecting rod bushing
removal/installation

Table 3-1 Special tool list (2 / 3)

Tool name Part No. Shape Use

SERVICE TOOLS

3-4

Oil seal sleeve installer
guide set

30691-13010

Oil seal sleeve installation of
crankshaft rear side

Piston installer 34491-00200 Piston installation

Oil pump bushing installer 32A91-00400 Oil pump bushing installation

Ring pliers 49160-90101 Snap ring removal/installation

Table 3-1 Special tool list (3 / 3)

Tool name Part No. Shape Use

4-1

DETERMINATION OF OVERHAUL

1. Determining overhaul timing ...........4-2

2. Testing compression pressure........4-3

DETERMINATION OF OVERHAUL

4-2

1. Determining overhaul timing

In most cases, the engine should be overhauled when the compression pressure of the engine becomes low. An increase in
engine oil consumption and blow-by gas are also considered to evaluate the engine condition. Besides, such symptoms as a
decrease in output, increase in fuel consumption, decrease in oil pressure, difficulty of engine starting and increase in noise are
also considered for judging the overhaul timing, although those symptoms are often affected by other causes, and are not
always effective to judge the overhaul timing. Decreased compression pressure shows a variety of symptoms and engine
conditions, thus making it difficult to accurately determine when the engine needs an overhaul. The following shows typical
problems caused by reduced compression pressure.

(1) Decreased output power
(2) Increased fuel consumption
(3) Increased engine oil consumption
(4) Increased blow-by gas through the breather due to worn cylinder liners and piston rings (Visually check the blow-by

amount)

(5) Increased gas leakage due to poor seating of inlet and exhaust valves
(6) Difficulty in starting
(7) Increased noise from engine parts
(8) Abnormal exhaust color after warm-up operation

The engine can exhibit these conditions in various combinations. Some of these problems are directly caused by worn engine
parts, while others are not. Phenomena described in items (2) and (6) will result from improper fuel injection volume, fuel
injection timing, worn plunger, faulty nozzles and also faulty conditions of electrical devices such as battery and starter. The
most valid reason to overhaul an engine is a decrease in compression pressure due to worn cylinder liners and pistons, as
described in item (4). In addition to this item, it is reasonable to take other problems into consideration for making the tota l
judgement.

DETERMINATION OF OVERHAUL

4-3

2. Testing compression pressure

CAUTION

(a) Be sure to measure the compression pressure for

all the cylinders. It is not a good practice to mea­sure the compression pressure for only one cylin­der, and presume the compression for the
remaining cylinders.

(b) Also be sure to check engine speed when measur-

ing the compression pressure, as compression
pressure varies with engine speed.

(c) Measuring the compression pressure at regular in-

tervals is important to obtain correct data.

(d) The compression pressure will be slightly higher in

a new or overhauled engine due to new piston
rings, valve seats, etc. Pressure will drop gradually
by the wear of these parts.

(e) Turn off the solenoid valve to stop fuel injection.

(1) Remove the glow plug from the cylinder head where

the compression pressure is to be measured.

(2) Atta ch the compre ssion gauge adapter to the glow plug

mount and connect compression gauge.

(3) Crank the engine with the starter, then read the

compression gauge indication while the engine is
running at the specified speed.

(4) If the compression pressure is lower than the limit,

overhaul the engine.

Testing compression pressure

Item Standard Limit

Compression pressure

3.2 MPa

{33 kgf/cm²}

[469 psi]

or more

2.8 MPa

{29 kgf/cm²}

[412 psi]

or less

Engine speed

300 min

-1

-

Oil and water tempera­tures

20 to 30°C

[68 to 86°F]

-

Gauge adapter
P/N:30691-21100

Compression
gauge
P/N:33391-02100

5-1

DISASSEMBLY OF BASIC ENGINE

1. Disassembling and inspecting cylinder

head and valve mechanism ............5-2

1.1 Removing rocker shaft assembly............. 5-3

1.2 Disassembling rocker shaft assembly...... 5-3

1.3 Removing cylinder head bolt.................... 5-3

1.4 Removing cylinder head assembly.......... 5-4

1.5 Removing valve and valve spring............5-4

1.6 Removing valve stem seal....................... 5-4

2. Disassembling and inspecting

flywheel...........................................5-5

2.1 Removing flywheel................................... 5-6

2.2 Removing rear plate................................ . 5-6

3. Disassembling and inspecting damper,
gear case, timing gear and

camshaft..........................................5-7

3.1 Removing crankshaft pulley and damper.5-9

3.2 Removing cover............ .... ... ... ... .... ... ... ... . 5-9

3.3 Removing timing gear case ................... 5-10

3.4 Measuring timing gear backlash............ 5-10

3.5 Measuring idler gear and camshaft gear

end play ........ .... ... ... ... ... .... ... ... ... ............ 5-11

3.6 Removing fuel injection pump.... .... ... ... .. 5-11

3.7 Removing oil pan................................... 5-11

3.8 Removing oil strainer............................. 5-11

3.9 Removing oil pump gear......... ... .... ... ... .. 5-12

3.10 Removing idler gear.......... ... ... ... .... ... ..... 5-12

3.11 Removing PTO drive gear ..................... 5-12

3.12 Removing camshaft............................... 5-12

3.13 Separating camshaft gear....... ... .... ... ... .. 5-13

3.14 Installing camshaft gear and thrust plate5-13

3.15 Removing front plate.............................. 5-13

3.16 Removing oil pump................................ 5-13

4. Disassembling and inspecting piston,
connecting rod, crankshaft and

crankcase......................................5-14

4.1 Removing connecting rod cap ....... ... ... .. 5-15

4.2 Removing carbon deposits from the upper part

of cylinder liner....................................... 5-15

4.3 Pulling out piston.................................... 5-15

4.4 Removing piston ring............................. 5-16

4.5 Removing piston pin and piston............. 5-16

4.6 Removing main bearing cap.................. 5-16

4.7 Removing crankshaft............................. 5-17

4.8 Removing tappet.. ... ... ... .... ... ... ... .... ... ... .. 5-17

DISASSEMBLY OF BASIC ENGINE

5-2

1. Disassembling and inspecting cylinder head and valve mechanism

Disassembling and inspecting cylinder head and valve mechanism

Disassembling sequence

1 Rocker cover 8 Rocker arm (EX) 15 Valve cotter
2 Adjusting screw 9 Rocker shaft spring 16 Valve retainer
3 Bolt (short) 10 Rocker shaft 17 Valve spring
4 Bolt (long) 11 Valve cap 18 Valve (IN)
5 Rocker shaft bracket 12 Push rod 19 Valve (EX)
6 Snap ring 13 Cylinder head bolt 20 Valve stem seal
7 Rocker arm (IN) 14 Cylinder head 21 Cylinder he ad gasket

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15
16

17

18

19

20

21

Replace

Replace

Replace

Fatigue, damage

Damaged threads,
worn rod contact surface

Wear

Wear

Worn valve cap contact
surface, clogged oil holes

Uneven wear on stems and faces,
damage, fatigue

Wear, clogged oil holes

Wear at both ends,
deflection

Crack, damage, carbon deposits,
water scale adhesion

Uneven wear

DISASSEMBLY OF BASIC ENGINE

5-3

1.1 Removing rocker shaft assembly

CAUTION

Always loosen shorter bolts first. Failing to do so may
cause the damage to the rocker shaft bracket.

(1) Loosen the rocker arm adjusting screws by rotating

about one turn.

(2) Loosen the shorter rocker bracket bolts first.
(3) Then, loosen the longer rocker bracket bolts.
(4) Remove the rocker bracket bolts, and remove the

rocker shaft assembly from the cylinder head.

(5) Remove push rods.

Removing rocker shaft assembly

1.2 Disassembling rocker shaft assembly

Remove the snap ring, disassemble the rocker shaft
assembly into the rocker arms, brackets, rocker shaft springs
and rocker shaft.
Note: (a) Be sure to arrange the parts of rocker shaft

assembly in the order of disassembly.
Reassemble the rocker shaft assembly in the
reverse order of disassembly by making sure of
the original combination of rocker arm and shaft
assembly so that the same clearance between the
rocker shaft and arms is restored when
reassembling.

(b) Do not remove the rocker bushing if it is not

faulty, and its inside diameter does not exceed the
limit.

Disassembling rocker shaft assembly

1.3 Removing cylinder head bolt

Loosen cylinder head bolts in the numerical order as shown
in the illustration.

Removing cylinder head bolt

Rocker arm

Adjusting screw

Rocker bracket bolt

Rocker shaft

Rocker shaft spring

Bracket

Rocker arm

Snap ring

1

5

9

13

17

21

25

22

18

14

10

6

2

3711151923 24 20

16 12 8

4

Number of bolt (25)

Front

DISASSEMBLY OF BASIC ENGINE

5-4

1.4 Removing cylinder head assembly

CAUTION

When removing the cylinder head gasket, be careful
not to damage the cylinder head or crankcase surface
with tools such as a screwdriver.

(1) Remove the cylinder head bolt.
(2) Remove the cylinder head assembly by lifting it up.

Note: If the cylinder head assembly cannot be removed due

to crimping of the cylinder head gasket, tap the thick
area on the side of the cylinder head using a plastic
hammer to give a shock.
Do not lift up the cylinder head by one person.
Use crane or lift up by two persons.

(3) Remove the gasket from the cylinder head.

Note: If there is a cylinder head problem, check the bolts for

tightness with a torque wrench before removing the
cylinder head bolts.

Removing cylinder head assembly

1.5 Removing valve and valve spring

Using a valve spring pusher, compress the valve spring
evenly and remove the valve cotters.
Note: If valves are reusable, mark each valve seat and the

mating valve for identifying their original positions.
Do not mix valve seats with other valve.

Removing valve and valve spring

1.6 Removing valve stem seal

Grab the valve stem seal with pliers and remove.
Note: Be sure to replace the valve stem seal with a new one

when reassembling the valve and valve spring.

Removing valve stem seal

Cylinder head

Valve spring pusher
P/N:30691-04500

Valve stem seal

DISASSEMBLY OF BASIC ENGINE

5-5

2. Disassembling and inspecting flywheel

Disassembling and inspecting flywheel

Disassembling sequence

1 Flywheel 2 Rear plate 3 Oil seal 4 Gasket

1

2

3

4

Replace

Crack,
abnormality of knock hole

Damaged threads

Lip wear, damage or aging

Crack, knock hole defect,
gear damage

DISASSEMBLY OF BASIC ENGINE

5-6

2.1 Removing flywheel

CAUTION

(a) Be careful not to cut yourself with the ring gear

when pulling out the flywheel.
Be careful not to drop or hit the flywheel when
removing.

(b) The person who holds the pulley must be very

careful to assure safety by communicating with the
person who is removing the flywheel.

(1) One personnel must firmly hold the pulley with a

wrench to prevent the flywheel from turning.

(2) Remove one bolt from the flywheel.
(3) Screw a guide bolt into the threaded hole of the bolt that

has been removed.

(4) Remove remaining bolts from the flywheel.
(5) Hold the flywheel firmly with both hands, and while

moving it back and forth, pull it out straight.

Note: The ring gear is shrink fitted to the flywheel. Do not

remove the ring gear unless it is defective.

Locking the flywheel

Removing flywheel

2.2 Removing rear plate

CAUTION

Be very careful not to damage the oil seal.

Remove the rear plate mounting bolts, and remove the rear
plate using a guide bolt.

Removing rear plate

Prevent the flywheel from rotating using a wrench.

Guide bolt

Oil seal

DISASSEMBLY OF BASIC ENGINE

5-7

3. Disassembling and inspecting damper, gear case, timing gear and camshaft

Disassembling and inspecting damper, gear case, timing gear and camshaft

Disassembling sequence

S6S-Y3T61HF

15

14

13

12

11

7

6

5

10

9

8

4

3

2

1

16

17

18

19

20

Replace

Replace

Replace

Replace

Replace

Wear

Clogging of oil
hole, wear

Wear, damage

Wear, damage

Lip wear,
damage or aging

Clogged
oil hole

Crack, abnormality of
knock hole

Crack, abnormality of
knock hole

Worn belt groove

Flaking,
uneven contact,
damage,
key groove
defect,
abnormal wear
bushings

Flaking,
uneven contact,
damage,
key groove defect,
abnormal wear
bushings

Replace

1 Damper 8 Oil pan 15 PTO drive gear, bearing
2 Crankshaft pulley 9 Oil strainer 16 Camshaft
3 Bearing case 10 Oil pump gear 17 Camshaft gear
4 Bearing case 11 Thrust plate 18 Thrust plate
5 Cover 12 Idler gear 19 Front plate
6 Timing gear case 13 PTO bearing case 20 Oil pump
7 Fuel injection pump 14 Oil pipe

DISASSEMBLY OF BASIC ENGINE

5-8

Disassembling and inspecting damper, gear case, timing gear and camshaft

Disassembling sequence

15

14

13

12

11

7

6

5

10

9

8

4

3

2

1

Replace

Replace

Replace

Replace

Replace

Wear

Clogging of oil
hole, wear

Wear, damage

Wear, damage

Lip wear,
damage or aging

Clogged
oil hole

Crack, abnormality of
knock hole

Crack, abnormality of
knock hole

Worn belt groove

Flaking,
uneven contact,
damage,
key groove
defect,
abnormal wear
bushings

Flaking,
uneven contact,
damage,
key groove defect,
abnormal wear
bushings

S6S-Y3T62HF

1 Damper 6 Oil pan 11 Camshaft
2 Crankshaft pulley 7 Oil strainer 12 Camshaft gear
3 Cover 8 Oil pump gear 13 Thrust plate
4 Timing gear case 9 Thrust plate 14 Front plate
5 Fuel injection pump 10 Idler gear 15 Oil pump

DISASSEMBLY OF BASIC ENGINE

5-9

3.1 Removing crankshaft pulley and dampe r

CAUTION

The bar that stops the crankshaft from turning may
come off. Pay special attention to safety.

(1) Screw two guide bolts into the threaded holes at the rear

end of the crankshaft. Stick a bar across the guide bolts
to prevent the crankshaft from turning.

(2) Remove the crankshaft pulley and damper.

Removing damper

Removing crankshaft pulley

3.2 Removing cover

Unscrew the cover mounting bolts, and remove the cover.

Removing cover

Removing cover

回り止めをする

(Front)

(Rear)

Guide bolt
(M12×1.25mm)

Prevent crankshaft
from rotating

Crankshaft pulley

Cover

S6S-Y3T62HF

Cover

Bearing case

S6S-Y3T61HF

DISASSEMBLY OF BASIC ENGINE

5-10

3.3 Removing timing gear case

CAUTION

The front plate is bolted to the crankcase from inside
the gear case. Do not attempt to remove the front plate
together with the gear case by tapping.

(1) Remove bolts from the timing gear case.
(2) Remove the timing gear case.

Note: Bolts have different lengths. Pay attention to the

positions of bolts to ensure correct reassembling.

Removing timing gear case

Removing timing gear case

3.4 Measuring timing gear backlash

Measure the backlash of the timing gears by using one of
the following two methods; measure the gear play with the
dial gauge plunger applied to a tooth flank on the pitch
circle at a right angle to the tooth axis, or measure the
clearance between gears by inserting a feeler gauge between
the gears at the tooth-to-tooth contacting area. Replace the
faulty gear pair if the limit is exceeded.

Note: With the injection pump gear attached to the pump,

install the injection pump gear to the front plate.

Measuring backlash timing gear

Gasket

Timing gear case

S6S-Y3T62HF

Gasket

Timing gear case

S6S-Y3T61HF

Item Standard Limit

Timing gear backlash

0.05 to 0.15 mm

[0.0020 to 0.0059 in.]

0.25 mm

[0.0098 in.]

DISASSEMBLY OF BASIC ENGINE

5-11

3.5 Measuring idler gear and camshaft gear

end play

Using a feeler gauge or dial gauge, measure the end play of
idler gear and camshaft gear.
If the measured value exceeds the limit, replace the thrust
plate with a new one.

Measuring idler gear and camshaft gear end play

3.6 Removing fuel injection pump

(1)

Remove the pump bracket mounting bolts.

(2) Unscrew the mounting bolts of fuel injection pump, and

remove the fuel injection pump.

Removing fuel injection pump

3.7 Removing oil pan

CAUTION

Do not insert a chisel or screwdriver between the oil
pan and crankcase to remove the oil pan, as it could
deform the oil pan flange.

(1) Turn the engine upside down.
(2) Remove bolts from the oil pan.
(3) To remove oil pan, tap flange corners of the oil pan

with a plastic hammer.

Removing oil pan

3.8 Removing oil strainer

(1)

Remove the oil strainer mounting bolts.

(2) Remove the oil strainer from the crankcase.

Removing oil strainer

Item Standard Limit

End play

Idler gear

0.05 to 0.20 mm

[0.0020 to 0.0079 in.]

0.35 mm

[0.0138 in.]

Camshaft

0.10 to 0.25 mm

[0.0039 to 0.0098 in.]

0.30 mm

[0.0118 in.]

Fuel injection pump

O-ring

Oil pan

Bolt

Oil strainer

DISASSEMBLY OF BASIC ENGINE

5-12

3.9 Removing oil pump gear

(1)

Remove the oil pump gear tightening nut.

(2) Remove the oil pump gear.

Removing oil pump gear

3.10 Removing idler gear

(1)

Remove the thrust plate bolt.

(2) Remove the idler gear while turning the gear.

Removing idler gear

3.11 Removing PTO drive gear

Remove the PTO drive gear tapping lightly with plastic
hammer.

Removing PTO drive gear

3.12 Removing camshaft

CAUTION

Be careful not to damage the cams of camshaft and
the bushings.

(1) Reverse the crankcase.
(2) Remove the thrust plate bolt.
(3) Remove the camshaft from the crankcase.
(4) Remove the tappet.

Removing camshaft

Oil pump gear

Idler gear

S6S-Y3T61HF

Camshaft gear

DISASSEMBLY OF BASIC ENGINE

5-13

3.13 Separating camshaft gear

Using hydraulic press, remove the camshaft gear and thrust
plate from the camshaft.
Note: Do not remove the camshaft gear from the camshaft

unless the camshaft gear or the thrust plate is
defective.

Separating gear from camshaft

3.14 Installing camshaft gear and thrust plate

(1)

Install the woodruff key and the thrust plate on the
camshaft.

Note: Be sure to install the thrust plate before installing the

camshaft gear.

(2) Heat the camshaft gear with a gear heater to a

temperature of about 150°C [302°F].

(3) Press fit the camshaft gear with press.

Installing camshaft gear and thrust plate

3.15 Removing front plate

(1)

Remove the front plate bolts.

(2) Remove the front plate from the crankcase.

Note: If it is difficult to remove the front plate, lightly tap it

with a plastic hammer.

Removing front plate

3.16 Removing oil pump

(1)

Remove the oil pump mounting bolts.

(2) Remove the oil pump.

Removing oil pump

Punch out with hydraulic press

Camshaft gear

Camshaft

Thrust plate

Press fit with
hydraulic press

Thrust plate

Camshaft gear

Camshaft

Front plate

Gasket

Oil pump

O-ring

DISASSEMBLY OF BASIC ENGINE

5-14

4. Disassembling and inspecting piston, connecting rod, crankshaft and crankcase

Disassembling and inspecting piston, connecting rod, crankshaft and crankcase

Disassembling sequence

1 Nut 8 Piston pin 15 Main bearin g (lower)
2 Connecting rod cap 9 Piston 16 Crankshaft
3 Connecting rod bearing 10 Connecting rod 17 Main bearing (upper)
4 No. 1 compression ring 11 Bearing cap bolt 18 Piston cooling nozzle
5 No. 2 compression ring 12 Main bearing cap 19 Tappet
6 Oil ring 13 Side seal 20 Crankcase
7 Snap ring 14 Thrust plate 21 Crank gear

20

19

18

21

17

16

15

14

14

14

13

12

11

10

9

8

7

6

5

4

3

2

1

Scratches on inside
and outside surfaces,
seizing, flaking

Damaged threads

Damaged threads

Cracks

Flaking, uneven contact

Scratches, cracks, dent,
clogged oil holes, wear

Wear

Wear

Wear, damage

Fatigue

Wear,
clogged oil holes

Cracks,
clogged oil holes

Serration for cracks, wear

Surface scratches, cracks,
damage, wear, carbon deposits

Adhesion of water scale, corrosion, flaking

Scratches on inside and
outside surfaces, seizing,
flaking, wear

Clogged oil hole

Note: When replacing the crankcase,
remove the parts installed in
the crankcase (relief valve,etc.)
carefully for reuse.

DISASSEMBLY OF BASIC ENGINE

5-15

4.1 Removing connecting rod cap

(1)

Lay the engine on its side.

(2) Mark the c ylinder number on the connecting rod and

connecting rod cap so that their combination is not
changed when reassembling.

(3) Remove the connecting rod caps.

Note: Mark the cylinder No. and upper/lower on connecting

rod bearings to ensure correct reassembling.

Removing connecting rod cap

4.2 Removing carbon deposits from the upper

part of cylinder liner

CAUTION

Be sure to remove carbon deposits from the upper part
of the cylinder liner before removing the piston, as it
could cause damage to the piston and piston ring.

Remove carbon deposits from the upper part of cylinder
liner using a carbon remover.
Note: Be careful not to damage the inner surface of the

cylinder liner.

Removing carbon deposits from the upper part of

cylinder liner

4.3 Pulling out piston

(1)

Turn the crankshaft to bring the piston to top dead
center.

(2) Using a piece of wood such a hammer hand le, push the

mating surface of the connecting rod cap, and pull the
piston and connecting rod upward from the cylinder.

Removing piston

DISASSEMBLY OF BASIC ENGINE

5-16

4.4 Removing piston ring

Remove the piston rings using piston ring pliers.

Removing piston ring

4.5 Removing piston pin and piston

(1)

Using ring pliers, remove the snap ring.

(2) Using a wooden bloc k and mallet, remove the piston

pin, and separate the piston from the connecting rod.

Note: (a) Do not tap the piston pin directly with a mallet.

(b) If the piston is stubborn, heat the piston with a

piston heater or in hot water.

Removing piston pin

4.6 Removing main bearing cap

(1)

Unscrew the main bearing cap bolts.

(2) Remove the main bearing cap.

Note: (a) Be careful not to damage the main bearings.

(b) Mark the bearings with their cylinder numbers.

Removing main bearing cap

Piston ring pliers
P/N:31391-12900

Snap ring pliers

DISASSEMBLY OF BASIC ENGINE

5-17

4.7 Removing crankshaft

CAUTION

Be careful not to damage bearings when removing the
crankshaft.

(1) Slowly lift the crankshaft straight up.
(2) Arrange the bearings in the order of disassembly so that

their original positions are restored when reassembling.

Note: (a) When raising the crankshaft, do not allow wire or

chain to come into contact with the crankshaft.
To avoid damage to the crankshaft when raising,
use a cloth belt or pad.

(b) Mark the bearings with their cylinder numbers.

4.8 Removing tappet

Remove the tappets using a magnet.
Note: Be sure to arrange the removed tappets for

reassembling to the same tappet hole.

Removing crankshaft

6-1

INSPECTION AND REPAIR OF BASIC ENGINE

1. Inspecting and repairing cylinder head

and valve mechanism .....................6-2

1.1 Measuring clearance between rocker

bushing and rocker shaft.......................... 6-2

1.2 Measuring valve stem outside diameter and

valve guide inside diameter ..................... 6-2

1.3 Replacing valve guide ... .... ... ... ... .... ... ... ... . 6-3

1.4 Inspecting valve face ............................... 6-4

1.5 Refacing valve face.................................. 6-4

1.6 Refacing valve seat.................................. 6-5

1.7 Replacing valve seat................................ 6-6

1.8 Lapping valve and valve seat................... 6-7

1.9 Measuring perpendicularity and free leng th of

valve spring............................................. . 6-7

1.10 Measuring distortion of the bottom surface of

the cylinder head...................................... 6-8

1.11 Measuring push rod runout...................... 6-8

1.12 Removing combustion jet......................... 6-9

2. Inspecting and repairing flywheel..6-10

2.1 Measuring flatness of flywheel............... 6-10

2.2 Measuring flywheel face and radial

runouts................................................... 6-10

2.3 Inspecting ring gear ............................... 6-10

2.4 Replacing ring gear . ... ... .... ... ... ... .... ... ... .. 6-10

2.4.1 Removing ring gear..................................6-10

2.4.2 Installing ring gear....................................6-10

3. Inspecting and repairing timing gear and

camshaft........................................6-11

3.1 Measuring timing gear backlash............ 6-11

3.2 Measuring idler gear and camshaft gear

end play ........ .... ... ... ... ... .... ... ... ... ............ 6-11

3.3 Measuring cam lift.................................. 6-11

3.4 Measuring camshaft runout ........... ... ... .. 6-12

3.5 Measuring camshaft journal

outside diameter .................................... 6-12

3.6 Measuring camshaft bushing

inside diameter....................................... 6-12

3.7 Replacing camshaft bushing.................. 6-13

3.7.1 Removing camshaft bushing....................6-13

3.7.2 Installing camshaft bushing......................6-13

3.8 Measuring idler bushing inside diameter and

idler shaft outside diameter.................... 6-13

3.9 Replacing idler shaft ..... .... ... ... ... .... ... ... .. 6-14

3.10 Measuring clearance between tappet and

tappet guide hole ................................... 6-14

3.11 Inspecting tappet.................................... 6-14

3.11.1Contact surface of camshaft.................... 6-14

3.11.2Contact surface of push rod .................... 6-14

3.12 Inspecting V-belt groove wear................ 6-15

3.13 Inspecting damper.................................. 6-15

4. Inspecting and repairing piston,
connecting rod, crankshaft and

crankcase .....................................6-16

4.1 Measuring crankcase top surface

distortion.................................................6-16

4.2 Measuring cylinder inside diameter........6-17

4.3 Measuring piston outside diameter........6-18

4.4 Measuring piston ring end gap...............6-18

4.5 Measuring clearance between piston ring

groove and piston ring............................ 6-19

4.6 Measuring piston pin bore diameter and piston

pin outside diameter............................... 6-19

4.7 Measuring piston protrusion...................6-20

4.8 Measuring clearance between connecting rod

bearing and crankpin.............................. 6-21

4.9 Measuring clearance between connecting rod

bushing and piston pin........................... 6-21

4.10 Replacing connecting rod bushing......... 6-22

4.11 Inspecting connecting rod bend and twist6-22

4.12 Inspecting connecting rod bearing.........6-23

4.13 Measuring connecting rod end play.......6-23

4.14 Weight difference of connecting rod assembly

in one engine...................................... .... 6-23

4.15 Measuring crankshaft journal

outside diameter..................................... 6-24

4.16 Measuring crankshaft crankpin

outside diameter..................................... 6-24

4.17 Grinding crankshaft................... ... ... ... .... 6-25

4.18 Measuring crankshaft end play..............6-26

4.19 Measuring crankshaft runout..................6-26

4.20 Replacing crankshaft gear .....................6-27

4.20.1Removing crankshaft gear....................... 6-27

4.20.2Installing crankshaft gear......................... 6-27

4.21 Inspecting oil seal contact surface.........6-27

4.22 Installing oil seal sleeve .........................6-28

4.23 Removing oil seal sleeve .......................6-28

4.24 Inspecting main bearing surface............6-29

4.25 Measuring clearance between main bearing

and crankshaft journal............................6-29

INSPECTION AND REPAIR OF BASIC ENGINE

6-2

1. Inspecting and repairing cylinder head and valve mechanism

1.1 Measuring clearance between rocker
bushing and rocker shaft

Measure the rocker assembly inside diameter and the rocker
shaft diameter. If the clearance exceeds the limit, replace
either rocker assembly or rocker shaft with a new one.

Measuring clearance between rocker bushing and

rocker shaft

1.2 Measuring valve stem out side diameter and
valve guide inside diameter

Measure the diameter at the top and bottom ends at right
angles to the outer and inner surfaces, since valve stems and
valve guides are more likely to wear at both ends. If the
outside diameter is less than the limit, or the clearance
exceeds the limit, replace either the valve or the valve guide
with a new one.

Measuring valve stem outside diameter

Measuring valve guide inside diameter

Item Nominal Standard Limit

Rocker bushing
inside diameter

ø 19 mm
[0.75 in.]

19.010 to 19.030 mm
[0.7484 to 0.7492 in.]

-

Rocker shaft
outside diameter

ø 19 mm
[0.75 in.]

18.980 to 19.000 mm
[0.7472 to 0.7480 in.]

-

Clearance
between rocker
bushing and shaft

-

0.010 to 0.050 mm

[0.0004 to 0.0020 in.]

0.070 mm

[0.0028 in.]

Measuring
direction

Measuring
direction

Item Nominal Standard Limit

Valve
stem
outside
diameter

Inlet

ø 8 mm

[0.31 in.]

7.940 to 7.955 mm

[0.3126 to 0.3132 in.]

7.900 mm

[0.3110 in.]

Exhaust

ø 8 mm

[0.31 in.]

7.920 to 7.940 mm

[0.3118 to 0.3126 in.]

7.850 mm

[0.3091 in.]

Clearance
between
valve stem
and valve
guide

Inlet -

0.065 to 0.095 mm

[0.0026 to 0.0037 in.]

0.150 mm

[0.0059 in.]

Exhaust -

0.080 to 0.115 mm

[0.0031 to 0.0045 in.]

0.200 mm

[0.0079 in.]

Valve guide
mounting dimension

14 mm

[0.55 in.]

13.9 to 14.1 mm

[0.547 to 0.555 in.]

-

Measuring
directions

Measuring
points

Inside
micrometer

Measuring
directions

Measuring
points

INSPECTION AND REPAIR OF BASIC ENGINE

6-3

1.3 Replacing valve guide

CAUTION

Because valve guides must be inserted to the speci­fied amount, be sure to use a valve guide installer.

(1) To remove valve guides, use a valve guide remover.

(2) To press-fit valve guides, use a valve guide installer.
(3) Check contacts between valves and valve seats after

replacing valve guides.

Pulling out valve guide

Press fitting valve guide

Valve guide remover
P/N:32A91-00300

Valve guide installer
P/N:32A91-00100

13.9 to 14.1 mm
[0.547 to 0.555 in.]

Press

INSPECTION AND REPAIR OF BASIC ENGINE

6-4

1.4 Inspecting valve face

Apply a thin coat of lead-free coloring paste on the valve
face, and strike the valve face against the valve seat using a
valve lapper to check for contact condition.
If the contact is not even, or any defects are found, or if the
limit is exceeded, reface or replace the valve.
Note: (a) Inspect the valve face after the valve guide is

repaired or replaced.

(b) Do not rotate the valve when pressing th e valve

face coated with lead-free coloring paste against
the valve seat.

(c) Always lap the valve and valve seat after the

valve has been refaced or replaced.

Checking valve face

Valve-to-valve seat contact

Measuring positions of valve seat and valve

1.5 Refacing valve face

If the valve face is significantly worn out, reface the valve
face using a valve refacer.
Note: (a) Grind the valve face using the valve refacer at the

specified angle.

(b) Secure the valve margin width equal to or greater

than the limit. If the dimensions after refacing
does not meet the specified values, replace the
valve with a new one.

Refacing valve face

Item Nominal Standard Limit

Valve seat

Valve seat
angle

30° - -

Valve
sinkage

Inlet

0.4 mm

[0.016 in.]

0.3 to 0.5 mm

[0.012 to 0.020 in.]

1.0 mm

[0.039 in.]

Exhaust

0.5 mm

[0.020 in.]

0.4 to 0.6 mm

[0.016 to 0.024 in.]

1.0 mm

[0.039 in.]

Seat width

1.4 mm

[0.055 in.]

1.26 to 1.54 mm

[0.0496 to 0.0606 in.]

1.8 mm

[0.071 in.]

Valve margin -

2.13 mm

[0.0839 in.]

Refacing

permissible

up to

1.83 mm

[0.0720 in.]

Valve lapper

Lead-free
coloring paste

Good Bad

Valve margin

Valve sinkage

Valve seat
angle

Seat width

Set the valve face
angle at the specified
angle.

Valve refacer

INSPECTION AND REPAIR OF BASIC ENGINE

6-5

1.6 Refacing valve seat

(1)

Use the valve seat cutter or valve seat grinder to refac e
the valve seat. After refacing, sand the valve seat lightly
using 400 grit sandpaper, inserting it between the cutter
and valve seat.

(2) Lap the valve in the valve seat.

Note: (a) Valve seat refacing should be kept to an absolute

minimum.

(b) If the valve seat width exceeds the limit due to

wear or refacing, replace the valve seat with a
new one.

(c) If the valve sinkage exceeds the limit after

refacing, replace the valve seat with a new one.

Refacing valve seat

Valve seat cutter

INSPECTION AND REPAIR OF BASIC ENGINE

6-6

1.7 Replacing valve seat

(1)

To remove the valve seat, weld a stud to the valve seat
as illustrated. Then, insert a rod into the valve guide
hole from the top of the cylinder head, and press out the
valve seat with the rod.

Note: Be careful not to allow spatters to adhere to the

machined surface of the cylinder head during
welding.

(2) Before inserting a new valve seat, measure valve seat

fitting bore diameter and valve seat outside diameter to
make sure the interference meets the specified value.

(3) Cool the valve seat at least for four minutes in liquid

nitrogen before fitting it into the cylinder head that is
kept at room temperature.

(4) Fit the cold valve seat into the cylinder head using a

insert caulking tool.

Replacing valve seat

Valve seat fitting bore

Driving in valve seat

Valve seat

Weld

Stud

Shaft

8 ± 0.1

[0.31 ± 0.004]

8 ± 0.1

[0.31 ± 0.004]

2 ± 0.1

[0.08 ± 0.004]

2 ± 0.1

[0.08 ± 0.004]

45°

45°

ø46

+0.025
0

[1.81

+0.0010

0.00

]

ø37

+0.025
0

[1.46

+0.0010

0.00

]

Inlet Exhaust

Unit: mm [in.]

Insert caulking tool
(Inlet) P/N:36791-00200, (Exhaust) P/N:34491-03020

INSPECTION AND REPAIR OF BASIC ENGINE

6-7

1.8 Lapping valve and valve seat

Always lap the valve against the valve seat after refacing the
valve seat or after replacing the valve.

(1) App ly a thin coat of lapping compound evenly to the

valve face.

Note: (a) Do not allow the compound to adhere on the

valve stem.

(b) Compound spreads more evenly if it is mixed

with a small amount of engine oil.

(c) Use medium-grain compound (120 to 150 mesh)

for initial lapping, then use fine-grain compound
(200 mesh or finer) for finishing.

(2) Use a valve lapper for lapping. Strike the valve against

the valve seat while rotating the valve little by little.

(3) Wash off the compound using diesel fuel.
(4) Coat the contact surfac e of the valve with engine oil,

then lap the valve again.

(5) Check valve-to-seat contact.

Coating valve with lapping

Lapping valve and valve seat

1.9 Measuring perpendicularity and free length
of valve spring

Measure the perpendicularity and free length of the valve
spring. If the measured free length and/or perpendicularity
exceed the limit, replace the valve spring with a new one. If
the measured set length and/or set load deviate from the
standard, replace the valve spring with a new one.

Squareness and free length of spring

Compound

Valve lapper

Item Standard Limit

Free length

48.85 mm

[1.9232 in.]

47.60 mm

[1.8740 in.]

Perpendicu­larity

A = 1.5° or less

B = 1.3 mm

[0.051 in.]

or less

Lf = 48.85 mm

[1.9232 in.]

B = 1.5 mm [0.059

in.]

at the end

Set length/set
load

43 mm [1.69 in.]/

176 to 196 N

{18 to 20 kgf}

[39 to 44 lbf]

43 mm [1.69 in.]/

147 N

{15 kgf}

[33 lbf]

A

B

Lf

Free length

Spring perpendicularity (gap)

INSPECTION AND REPAIR OF BASIC ENGINE

6-8

1.10 Measuring distortion of the bottom surface
of the cylinder head

CAUTION

Refacing of cylinder head should be kept to an abso­lute minimum.
Excessive grinding of the cylinder head may result in
defects such as defective combustion and stamping
(contact between piston and valve).

With a straight edge placed on the bottom face of the
cylinder head, measure the bottom face distortion using a
feeler gauge. If the measurement exceeds the limit, grind the
bottom face using a surface grinder.

Note: Do not grind the surfaces more than 0.2 mm [0.008

in.] in total (cylinder head bottom surface plus
crankcase top surface).

Measuring distortion of the bottom surface of the

cylinder head

1.11 Measuring push rod runout

Measure the runout of each push rod. Replace if the limit is
exceeded.

Measuring push rod runout

Item Standard Limit

Distortion of bot­tom face

0.05 mm

[0.0020 in.] or less

0.20 mm

[0.0079 in.]

Item Standard Limit Remark

Push rod
runout

0.6 mm

[0.024 in.] or less

0.6 mm

[0.024 in.]

Total indicated reading

(TIR)

1/21/2

Push rod

INSPECTION AND REPAIR OF BASIC ENGINE

6-9

1.12 Removing combustion jet

Replace the combustion jet only when it has a defect or
crack.

(1) Inse rt a round bar (approx; ø6 mm [0.24 in.]) into glow

plug hole, and tap the combustion jet inner face
perimeter lightly to pull out the combustion jet.

(2) When installing the combustion jet, align the

positioning hole and jet nozzle with the center of
cylinder, press fit by tapping with plastic hammer.

Removing combustion jet

Press-fitting combustion jet

Round rod

Combustion jet

Combustion jet

Jet nozzle

INSPECTION AND REPAIR OF BASIC ENGINE

6-10

2. Inspecting and repairing flywheel

2.1 Measuring flatness of flywheel

Place the flywheel on a surface plate and move a dial gauge
on the friction surface of the flywheel to measure the
flatness.
Grind the friction surface of the flywheel if the limit is
exceeded.

Measuring flatness of flywheel

2.2 Measuring flywheel face and radial runouts

Measure the runouts of the flywheel in the installed
condition. If the measured value exceeds the standard,
check the bolt for looseness as well as the accumulation of
foreign matter on the mounting face.

Measuring flywheel face and radial runout

2.3 Inspecting ring gear

Inspect the ring gear for a missing tooth or worn teeth, and
if defects are found, replace the ring gear.

2.4 Replacing ring gear

2.4.1 Removing ring gear

(1) He at the ring gear evenly using an acetylene torch or

other appropriate heat source.

(2) With a rod placed on the periphery of ring gear, tap the

rod with a hammer evenly around the ring gear, and
remove the ring gear.

2.4.2 Installing ring gear

(1) He at the ring gear evenly up to approx. 150°C [176°F]

with an appropriate heater.

(2) Insta ll the ring gear onto the flywheel with the no -ge ar-

chamfering side faced to the flywheel.

Note: Do not heat the ring gear excessively.

Removing ring gear

Item Standard Limit

Flywheel flatness

0.15 mm

[0.0059 in.] or less

0.50 mm

[0.0197 in.]

Item Standard Limit

Flywheel face runout
and radial runout

0.15 mm

[0.0059 in.] or less

0.50 mm

[0.0197 in.]

Face runout
measuring point

Radial runout
measuring point

Ring gear

Flywheel

INSPECTION AND REPAIR OF BASIC ENGINE

6-11

3. Inspecting and repairing timing gear and camshaft

3.1 Measuring timing gear backlash

Measure the backlash of the timing gears by using one of
the following two methods; measure the gear play with the
dial gauge plunger applied to a tooth flank on the pitch
circle at a right angle to the tooth axis, or measure the
clearance between gears by inserting a feeler gauge between
the gears at the tooth-to-tooth contacting area. Replace the
faulty gear pair if the limit is exceeded.

Note: With the injection pump gear attached to the pump,

install the injection pump gear to the front plate.

Measuring timing gear backlash

3.2 Measuring idler gear and camshaft gear
end play

Using a feeler gauge or dial gauge, measure the end play of
idler gear and camshaft gear.
If the measured value exceeds the limit, replace the thrust
plate with a new one.

Measuring idler gear and camshaft gear end play

3.3 Measuring cam lift

Measure the minor and major axes of cam to determine cam
lobe lift. If the lift is less than the limit, replace the camshaft
with a new one.

Measuring cam lift

Item Standard Limit

Timing gear backlash

0.05 to 0.15 mm

[0.0020 to 0.0059 in.]

0.25 mm

[0.0098 in.]

Item Standard Limit

End play

Idler gear

0.05 to 0.20 mm

[0.0020 to 0.0079 in.]

0.35 mm

[0.0138 in.]

Camshaft

0.10 to 0.25 mm

[0.0039 to 0.0098 in.]

0.30 mm

[0.0118 in.]

Item Nominal Standard Limit

Cam
lift

Inlet

6.682 mm

[0.2631 in.]

6.382 to 6.782 mm

[0.2513 to 0.2670 in.]

6.182 mm

[0.2434 in.]

Exhaust

6.722 mm

[0.2646 in.]

6.422 to 6.822 mm

[0.2528 to 0.2686 in.]

6.222 mm

[0.2450 in.]

D

1

D

2

Measuring
locations

Measuring
directions

INSPECTION AND REPAIR OF BASIC ENGINE

6-12

3.4 Measuring camshaft runout

Measure the camshaft runout using a dial gauge. If the limit
is exceeded, correct the camshaft using a press, or replace
the camshaft with a new one.
Note: With a dial gauge set on the camshaft, rotate the

camshaft one turn and read the gauge indication.

Measuring camshaft runout

3.5 Measuring camshaft journal outside diame­ter

Measure the diameter of each camshaft journal in two
direction at right angles to each other. If the limit is
exceeded, replace the camshaft with a new one.

Measuring camshaft journal outside diameter

3.6 Measuring camshaft bushing inside diame­ter

With the camshaft bushings installed in the crankcase,
measure the inside diameters using a cylinder gauge. If the
limit is exceeded, replace the bushing with a new one.

Measuring camshaft bushing inside diameter

Item Standard Limit Remark

Camshaft runout

0.04 mm

[0.0016 in.] or less

0.10 mm

[0.0039 in.]

TIR

Item Standard Limit

Camshaft journal
outside diameter

No. 1, 2, 3

53.94 to 53.96 mm

[2.1236 to 2.1244 in.]

53.90 mm

[2.1220 in.]

No. 4

52.94 to 52.96 mm

[2.0842 to 2.0850 in.]

52.90 mm

[2.0827 in.]

Measuring
locations

Measuring
directions

Item Standard Limit

Clearance between camshaft
journal and camshaft bushing

0.07 to 0.11 mm

[0.0028 to 0.0043 in.]

0.15 mm

[0.0059 in.]

Measuring
directions

INSPECTION AND REPAIR OF BASIC ENGINE

6-13

3.7 Replacing camshaft bushing

3.7.1 Removing camshaft bushing

(1) Insta ll a camshaft bushing installer set to the camshaft

bushing.

(2) Remove the camshaft bushing by tapping the end of the

rod of camshaft bushing installer set.

Removing camshaft bushing

3.7.2 Installing camshaft bushing

(1) Install the camshaft bushing to a camshaft bushing

installer set.

(2) When driving in a bushing, tap the end of camshaft

bushing installer rod so that the oil hole in the bushing
aligns with the oil hole of the oil gallery.

Installing camshaft bushing

3.8 Measuring idler bushing inside diameter
and idler shaft outside diameter

Measure the idler bushing inside diameter and idler shaft
outside diameter, and calculate the clearance between them.
If the measured value exceeds the limit, locate the defective
part and replace it.

Measuring idler bushing inside diameter and idler shaft

outside diameter

Rod

Camshaft bushing
installer set
P/N:30691-00010

Bushing

Adapter

Rod

Oil hole

Piece

Bushing

Adapter

Camshaft bushing
installer set
P/N:30691-00010

Item Standard Limit

Clearance between
idler bushing and idler shaft

0.009 to 0.050 mm

[0.0004 to 0.0020 in.]

0.100 mm

[0.0039 in.]

Measuring
direction

Measuring
position

INSPECTION AND REPAIR OF BASIC ENGINE

6-14

3.9 Replacing idler shaft

To remove the idler shaft, use the idler shaft puller.
Note: When installing the idler shaft into the crankcase,

orient the idler shaft so that its oil hole faces the upper
crankcase.

Replacing idler shaft

3.10 Measuring clearance between tappet and
tappet guide hole

Measure clearance between the tappet and tappet hole.
Replace the tappet with a new one if the limit is exceeded.

Measuring clearance between tappet and tappet guide

hole

3.11 Inspecting tappet

3.11.1 Contact surface of camshaft

Inspect the cam contact surface of the tappets. Fit new
tappets if the surface is excessively worn or damaged.

Contact surface of camshaft

3.11.2 Contact surface of push rod

(1) App ly a lead-free coloring paste on the push rods, and

check the contact surface.

(2) Check that the push rod contacts the tappet

concentrically. If it does, replace the tappet and push
rod with new one.

Contact surface of push rod

Item Nominal Standard

Interference between shaft and
crankcase hole

ø 35 mm

[1.38 in.]

0.035T to 0.076T mm
[0.0014 to 0.0030 in.]

Idler shaft puller
P/N:MH061077

Item Standard Limit

Tappet guide hole
inside diameter

14.000 to 14.018 mm
[0.5512 to 0.5519 in.]

14.100 mm
[0.5551 in.]

Clearance between tappet
and tappet guide hole

0.016 to 0.052 mm

[0.0006 to 0.0020 in.]

0.08 mm

[0.0031 in.]

Measuring
points

Measuring
directions

Good

Bad

Bad

A

A

Good Bad

Push rod should not contact tappet concentrically.

It should be round.
Dents should not
exist.

Section A-A

INSPECTION AND REPAIR OF BASIC ENGINE

6-15

3.12 Inspecting V-belt groove wear

Check the V-belt groove of the pulley for wear. Attach a
new V-belt around the pulley, apply high tension and
measure the sinkage of V-belt.
If the wear appears excessively, and the belt top surface
sinks 1.6 mm [0.06 in.] or more down from the top edge of
groove, replace the pulley with a new one.
If the pulley has two or more grooves for belt, and the
difference of the wear amount between grooves is
significant, replace the pulley with a new one.

Inspecting V-belt groove wear

3.13 Inspecting damper

(1)

Check the damper for cracks around the outer
periphery, swelling and/or cracks in the end plate,
silicone oil leakage and discoloration and separation of
coating due to thermal effect.
If any defect is found, replace the damper with a new
one.

(2) With the damper installed on the engine, measure the

face and radial runouts of the damper in the following
manner: Attach the dial gauge plunger on the outer
circumference of the damper to measure the radial
runout, or on the end face near the perimeter to measure
the face runout, and slowly turn the crankshaft. If the
limit is exceeded, replace the damper with a new one.

Measuring face and radial runout of damper

1.6 mm [0.06 in.]
or less

Item Nominal Standard Limit

Perpendicularity
runout

0.5 mm

[0.020 in.] or less

1.5 mm

[0.059 in.]

Replace with a
new one after
operating 8000
hours.

Periphery
runout

0.5 mm

[0.020 in.] or less

1.5 mm

[0.059 in.]

Face runout

Radial runout

INSPECTION AND REPAIR OF BASIC ENGINE

6-16

4. Inspecting and repairing piston, connecting rod, crankshaft and crankcase

4.1 Measuring crankcase top surface distor­tion

CAUTION

Refacing of cylinder head should be kept to an abso­lute minimum.
Excessive grinding of the cylinder head may result in
defects such as defective combustion and stamping
(contact between piston and valve).

Apply a straight edge to the top surface of the crankcase and
measure its distortion using a feeler gauge. If the distortion
exceeds the limit, grind the crankcase using a surface
grinder.
Note: Do not overgrind the cylinder head, as the piston

protrusion deviates from the standard value.

Note: Do not grind the surfaces more than 0.2 mm

[0.0079 in.] in total (cylinder head bottom surface
plus crankcase top surface).

Measuring crankcase top surface distortion

Item Standard Limit

Flatness of top surface

0.05 mm

[0.0020 in.] or less

0.20 mm

[0.0079 in.]

INSPECTION AND REPAIR OF BASIC ENGINE

6-17

4.2 Measuring cylinder inside diameter

(1)

Measure the inside diameter of the cylinder at three
levels, i.e., upper (with much stepped wear), middle,
and lower levels, in both directions parallel to and
perpendicular to the crankshaft direction.

(2) If the measurement is between the repair limit and

replacement limit, re-bore the cylinder to +0.25 mm
[0.0098 in.] or +0.5 mm [0.0197 in.] oversize. Hone the
re-bored cylinder to the accuracy of the standard.

(3) Use an oversize piston and piston rings to fit the re-

bored cylinder.

(4) If the cylinder is worn unevenly, select an oversize

diameter that ensures complete roundness when the
cylinder is re-bored to the maximum. All cylinders
must be re-bored to the same oversize diameter if one
cylinder is re-bored.

(5) If the cylinder has a slight wear and is reused after

replacing only the piston rings, remove the steps in
worn portion in the upper part of the cylinder using a
ridge reamer. Hone it as necessary.

Measuring cylinder sleeve inside diameter

Refacing using a ridge reamer

Item Standard Limit

Cylinder
inside diameter

94.000 to 94.035 mm
[3.7008 to 3.7022 in.]

Repair limit:

94.200 mm [3.7087 in.]
Replace limit:

94.700 mm [3.7283 in.]

Circularity

0.01 mm

[0.0004 in.] or less

-

Cylindricity

0.015 mm

[0.0006 in.] or less

-

11 [0.43]

80 [3.15]

150 [5.91]

Measuring
directions

Measuring
points

Unit: mm [in.]

INSPECTION AND REPAIR OF BASIC ENGINE

6-18

4.3 Measuring piston outside diameter

(1)

Measure the piston outside diameter of the piston skirt
at right angles to the piston pin. If it exceeds the limit,
replace the piston with a new piston. When replacing
piston, be sure to select a piston so that the piston
weight difference in one engine is kept within the
permissible range.

(2) The piston weight is stamped on the top of piston head.

The piston weight is stamped on the top of piston head.

Measuring piston outside diameter

Piston weight stamp location

4.4 Measuring piston ring end gap

Place the piston ring in a gauge or a new sleeve to measure
the ring end gap. If the limit is exceeded, replace all the
rings as a set.
Note: Use a piston to push the piston ring squarely into the

gauge or the sleeve.

Measuring piston ring end gap

Item Nominal Standard Limit

Piston
outside
diameter
(at piston
skirt)

STD

ø 94 mm

[3.70 in.]

93.955 to 93.985 mm
[3.6990 to 3.7002 in.]

93.770 mm
[3.6917 in.]

0.25 mm
[0.0098 in.]
/OS

94.205 to 94.235 mm
[3.7089 to 3.7100 in.]

94.020 mm
[3.7016 in.]

0.50 mm
[0.0197 in.]
/OS

94.455 to 94.485 mm
[3.7187 to 3.7199 in.]

94.270 mm
[3.7114 in.]

Weight difference in one engine

5 g

[0.2 oz.] or less

-

Measuring point

Direction at right
angles to piston pin

Identification
mark

Front mark

Weight stamp

Number stamp

Item Standard Limit

Closed
gap
of ring

No. 1
compression ring

0.30 to 0.50 mm

[0.0118 to 0.0197 in.]

1.50 mm

[0.0591 in.]

No. 2
compression ring

0.50 to 0.70 mm

[0.0197 to 0.0276 in.]

Oil ring

0.30 to 0.50 mm

[0.0118 to 0.0197 in.]

End gap

Thickness gauge

INSPECTION AND REPAIR OF BASIC ENGINE

6-19

4.5 Measuring clearance between piston ring
groove and piston ring

CAUTION

Remove carbon deposits from pistons and check the
entire circumference of the piston.

(1) Remove deposits such as carbon from each ring groove.
(2) Check each ring groove for wear or damage. If it is

worn or damaged, replace the piston with a new one.

(3) Insert the piston ring into the piston ring groove. Apply

a straight edge and insert thickness gauges to measure
the clearance between ring and ring groove.
If the limit is exceeded, replace the piston ring with a
new one.

(4) Wh en the piston ring has been replaced, measure the

clearance again, and if the limit is exceeded, then
replace the piston with a new one.

Measuring clearance between piston ring groove and

piston ring

4.6 Measuring piston pin bore diameter and
piston pin outside diameter

Measure the piston pin bore diameter and piston pin outside
diameter. Replace if the limit is exceeded.

Measuring piston pin bore diameter and piston pin

outside diameter

Item Standard Limit

Clearance
between
piston
ring
groove

No. 1
compression ring

0.07 to 0.11 mm

[0.0028 to 0.0043 in.]

0.200 mm

[0.0079 in.]

No. 2
compression ring

0.045 to 0.085 mm

[0.0018 to 0.0033 in.]

0.150 mm

[0.0059 in.]

Oil ring

0.020 to 0.060 mm

[0.0008 to 0.0024 in.]

0.150 mm

[0.0059 in.]

Item Nominal Standard Limit

Piston pin
outside diameter

ø 30 mm

[1.18 in.]

29.994 to 30.000 mm
[1.1809 to 1.1811 in.]

-

Clearance between
piston pin

-

0.000 to 0.016 mm

[0.0000 to 0.0006 in.]

0.050 mm

[0.0020 in.]

Measuring
points

Measuring
directions

INSPECTION AND REPAIR OF BASIC ENGINE

6-20

4.7 Measuring piston protrusion

CAUTION

Piston protrusion must always meet the standard, as
the amount of protrusion not only influences on the
engine performance, but also it is important to prevent
valve interference.

Measure the protrusion of each piston following the
instructions below. If the measured value does not meet the
standard, inspect the clearances between various parts
involved.

(1) Bring the piston to top dead center.
(2) App ly the dial gauge plunger to the top surface of the

crankcase, and zero the dial gauge.

(3) Measure the protrusion at four points on the piston

head, and calculate the mean value.

Note: Subtract the mean value from the thickness of the

gasket compressed by tightening the cylinder head,
and the clearance between the piston top and cylinder
head will be determined.

Measuring piston protrusion

Item Standard

Piston protrusion

-0.25 to 0.15 mm

[-0.0098 to 0.0059 in.]

Compressed thickness of
cylinder head gasket

1.15 to 1.25 mm

[0.0453 to 0.0492 in.]

INSPECTION AND REPAIR OF BASIC ENGINE

6-21

4.8 Measuring clearance between connecting
rod bearing and crankpin

CAUTION

When grinding crankpins, be sure to grind all the pins
to the same size.
Finish the fillet radius to the specified dimension.

(1) Reassemble the bearing into the big end of the

connecting rod.

(2) Tighten the connecting rod cap bolts to the specified

torque.

(3) Measure the inside diameter of the connecting rod

bearing.

(4) Measure the outside diameter of the crankpin.
(5) Calculate the clearance from the difference between the

inside diameter of the connecting rod bearing and
outside diameter of the crankpin.

(6) Replace the connecting rod bearing if the clearance

exceeds the limit.

(7) Measure the clearance between the connecting rod

bearing and the crankpin again. Use the undersize
bearing if the limit is exceeded.

(8) If an unde rsize bearing is used, grind the crankpin to

the specified undersize.

Measuring connecting rod bearing inside diameter

Measuring crankpin diameter

4.9 Measuring clearance between connecting
rod bushing and piston pin

Measure the inside diameter of the connecting rod bushing
and the outside diameter of the piston pin. Replace if the
limit is exceeded.

Measuring connecting rod bushing inside diameter

Item Nominal Standard Limit

Crankpin
outside diameter

ø 58 mm

[2.28 in.]

57.955 to 57.970 mm
[2.2817 to 2.2823 in.]

57.800 mm

[2.2756 in.]

Clearance between
crankpin and
connecting rod bearing
(oil clearance)

-

0.030 to 0.090 mm

[0.0012 to 0.0035 in.]

0.200 mm

[0.0079 in.]

Measuring
directions

Measuring
points

54 ± 5 N·m
{5.5 ± 0.5 kgf·m}
[40 ± 3.6 lbf·ft]

Measuring
directions

Measuring
points

Item Nominal Standard Limit

Bushing
inside diameter

ø 30 mm

[1.18 in.]

30.020 to 30.045 mm
[1.1819 to 1.1829 in.]

-

Clearance between
connecting rod
bushing

-

0.020 to 0.091 mm

[0.0008 to 0.0036 in.]

0.120 mm

[0.0047 in.]

Measuring
directions

Measuring
points

INSPECTION AND REPAIR OF BASIC ENGINE

6-22

4.10 Replacing connecting rod bushing

Use a connecting rod bushing installer to replace the
connecting rod bushing.

(1) With the bushing joints oriented as shown in the

illustration, align the oil hole of bushing with the oil
hole of connecting rod, and press-fit the connecting rod
bushing into the connecting rod.

(2) After press-fitting, insert the piston pin, and check for

smooth movement of the connecting rod and piston
without looseness.

Replacing connecting rod bushing

4.11 Inspecting connecting rod bend and twist

(1)

Measure the dimensions of C and L in the illustration to
check bend and twist of the connecting rod. Straighten
the connecting rod with a press to meet the standard.
If the standard is exceeded after correction, replace the
connecting rod with a new one.

(2) In general, a connecting rod aligner is used to check

bend and twist.

Note: Before checking bend, tighten the conne cting rod cap

to the specified torque.

(3) To inspect the connecting rod with the piston installed,

turn the piston upside down and place it on a surface
plate. Insert a round bar having the same diameter as
the crankpin into the big-end bore, and measure the
height of the bar using a dial gauge.

Inspecting connecting rod bend and twist

Using a connecting rod aligner to measure rod bend

and twist

Measuring with a dial gauge

Connecting rod bushing installer
P/N:32A91-00500

Match marks side

Oil hole

Bushing joint

Item Standard Limit

Connecting rod
bend and twist

0.05/100 mm

[0.0020/3.94 in.] or less

0.15 mm

[0.0059 in.]

C

C

L

L

54 ± 5 N·m {5.5 ± 0.5 kgf·m}
[40 ± 3.6 lbf·ft]

Piston pin

Connecting rod bend

Connecting rod twist

Unit: mm [in.]

3.94

[ ]

0.05
100

C

L

0.0020

3.94

[ ]

0.05
100

C

L

0.0020

C

A

B

D

Unit: mm [in.]

D

C

100

0.05

3.94

0.0020

[ ]

INSPECTION AND REPAIR OF BASIC ENGINE

6-23

4.12 Inspecting connecting rod bearing

Inspect the connecting rod bearings. If any defect is found,
replace it with a new one.

Inspecting connecting rod bearing

4.13 Measuring connecting rod end play

(1)

Install the connecting rods onto the respective
crankpins and tighten the connecting rod cap bolts to
the specified torque.

(2) Measure the clearance of the crank arm (end play) at

two positions (above and below the crankpin).

(3) If the limit is exceeded, replace the connecting rod with

a new one.

Measuring connecting rod end play

4.14 Weight difference of connecting rod
assembly in one engine

When replacing a connecting rod, be sure to check the
weight rank of the connecting rod. All the connecting rods
must be of the same weight rank in an engine.

Weight difference in connecting rod assembly

Flaking

Scratches

Fusion

Item Standard Limit

Connecting rod end play

0.15 to 0.35 mm

[0.0059 to 0.0138 in.]

0.50 mm

[0.0197 in.]

54 ± 5 N·m
{5.5 ± 0.5 kgf·m}
[40 ± 3.6 lbf·ft]

Feeler gauge

Item Tolerance on weight

Weight difference of
connecting rod assembly

10 g

[0.35 oz.] or less

A

Weight rank mark

Mating mark
for assembly

INSPECTION AND REPAIR OF BASIC ENGINE

6-24

4.15 Measuring crankshaft journal outside diam­eter

Measure the crankshaft journal diameter using a
micrometer. Check the crankshaft journal for circularity,
cylindricity and clearance between the bearing and journal.
If the measurement value is below the repair limit, grind the
journal to fit the undersize bearing. If the measurement
value is below the service limit, replace the crankshaft with
a new one.

Measuring crankshaft journal outside diameter

4.16 Measuring crankshaft crankpin outside
diameter

Measure the crankpin outside diameter using a micrometer.
Check the crankpin for roundness, cylindricality, and the
clearance with the bearing. If the measurement value is
below the limit, grind the journal to fit the undersize
bearing. If the measurement value is below the service limit,
replace the crankshaft with a new one.

Measuring crankpin diameter

Item Nominal Standard Limit

Outside diameter

ø 78 mm

[3.07 in.]

77.955 to 77.970 mm

[3.0691 to 3.0697 in.]

77.850 mm

[3.0650 in.]

(Repair)

77.100 mm

[3.0354 in.]

(Replace)

Roundness -

0.01 mm

[0.0004 in.] or less

0.03 mm

[0.0012 in.]

Cylindricity -

0.01 mm

[0.0004 in.] or less

0.03 mm

[0.0012 in.]

Parallelism -

Pin maximum

defection:

0.01 mm

[0.0004 in.] or less

-

Measuring
direction

Measuring
position

Item Nominal Standard Limit

Outside diameter

ø 58 mm

[2.28 in.]

57.955 to 57.970 mm

[2.2817 to 2.2823 in.]

57.800 mm

[2.2756 in.]

Roundness -

0.01 mm

[0.0004 in.] or less

0.03 mm

[0.0012 in.]

Cylindricity -

0.01 mm

[0.0004 in.] or less

0.03 mm

[0.0012 in.]

Parallelism -

Pin maximum

defection:

0.01 mm

[0.0004 in.] or less

-

Measuring
directions

Measuring
points

INSPECTION AND REPAIR OF BASIC ENGINE

6-25

4.17 Grinding crankshaft

CAUTION

(a) When grinding crank journals, be sure to grind all

the journals to the same size.

(b) Finish the fillet radius to the specified dimension.

Grind the crankshaft journal (or pin) to the diameter that fits
the inside diameter of the next undersize main (or
connecting) bearing. By doing so, the fitness check with an
actual bearing can be omitted.
When grinding, be careful not to change the fillet radius and
width. If the surface hardness is considered to have been
reduced considerably, re-harden the crankshaft and check
for flaws by means of magnetic particle inspection.
Ensure that the surface finish accuracy of the crankpins and
journals is kept within the standard even after the correction
by grinding.

Finished dimension of fillet R

Item Undersize Finished size

Crank
journal

0.25 mm

[0.0098 in.]

77.705 to 77.720 mm

[3.0592 to 3.0598 in.]

0.50 mm

[0.0197 in.]

77.455 to 77.470 mm

[3.0494 to 3.0500 in.]

0.75 mm

[0.0295 in.]

77.205 to 77.220 mm

[3.0396 to 3.0402 in.]

Crankpin

0.25 mm

[0.0098 in.]

57.705 to 57.720 mm

[2.2718 to 2.2724 in.]

0.50 mm

[0.0197 in.]

57.455 to 57.470 mm

[2.2620 to 2.2626 in.]

0.75 mm

[0.0295 in.]

57.205 to 57.220 mm

[2.2522 to 2.2528 in.]

R3 mm
[0.12 in.]

R3 mm
[0.12 in.]

R3 mm
[0.12 in.]

INSPECTION AND REPAIR OF BASIC ENGINE

6-26

4.18 Measuring crankshaft end play

(1)

Measure the crankshaft end play (clearance between the
crank arm at the thrust force receiving journal and the
bearing cap with thrust plate attached). If the limit is
exceeded, replace the thrust plate with a new one.

(2) If the limit is still exceeded after a new thrust plate has

been installed, use an oversize thrust plate.

Note: In general, the rear thrust bearing wears faster than

the front thrust bearing. Therefore, in most cases, the
correction is achieved by replacing the rear thrust
plate with the next oversize one.

Width of crankshaft thrust journal

Measuring crankshaft end play

4.19 Measuring crankshaft runout

Support the crankshaft at the front and rear journals with V­blocks, and measure the crankshaft runout at the center
journal using a dial gauge. If the runout deviates from the
standard only slightly, grind the crankshaft to repair. If the
runout exceeds the standard considerably, straighten the
crankshaft using a press.
If the limit is exceeded, replace the crankshaft.
If the crankshaft has been repaired by grinding or pressing,
inspect the crankshaft for cracks and other harmful damage
using a magnetic particle method.

Measuring crankshaft runout

Item Standard Limit

Crankshaft end play

0.100 to 0.264 mm

[0.0039 to 0.0104 in.]

0.300 mm

[0.0118 in.]

Crankshaft thrust size after grinding

Item

OS, used

on one side

OS, used

on both sides

Tolerance

+0.15 mm
[+0.0059 in.] OS

31.15 mm

[1.2264 in.]

31.30 mm

[1.2323 in.]

0

+0.039

mm

[

0.00

+0.0015

in.]+0.30 mm

[+0.0118 in.] OS

31.30 mm

[1.2323 in.]

31.45 mm

[1.2382 in.]

31

+0.039
0

mm

[1.22

+0.015

0.00

in.]

Item Standard Limit Remark

Crankshaft
runout

0.04 mm

[0.0016 in.] or less

0.10 mm

[0.0039 in.]

TIR

INSPECTION AND REPAIR OF BASIC ENGINE

6-27

4.20 Replacing crankshaft gear

4.20.1 Removing crankshaft gear

Using a gear puller, remove the gear from the crankshaft.
Note: Do not strike the gear with a hammer.

Removing crankshaft gear

4.20.2 Installing crankshaft gear

(1) Install the key on the crankshaft.
(2) Press-fit the gear fully in alignment with the key.

Installing crankshaft gear

4.21 Inspecting oil seal contact surface

Inspect the oil seal contact surface located on the crankshaft
rear part. If the crankshaft wears due to the oil seal, replace
the oil seal and the oil seal sleeve with new spare parts.

Inspecting oil seal contact surface (1)

Crankshaft gear

Puller
P/N:MH061326

Aligning position

Key

Crankshaft gear

Oil seal

Oil seal
contact surface

Oil seal sleeve

INSPECTION AND REPAIR OF BASIC ENGINE

6-28

4.22 Installing oil seal sleeve

CAUTION

Be careful not to dent or damage the oil seal sleeve
circumference.

When installing the oil seal sleeve, apply the oil to the
inside of the oil seal sleeve, and drive it into the crankshaft
by using oil seal sleeve installer set.
When the engine is operated again and the oil seal sleeve
wears, remove the oil seal sleeve by using following method
and replace the oil seal assembly (oil seal and oil seal
sleeve) with the new spare parts.

Installing oil seal sleeve

Inspecting oil seal contact surface (2)

4.23 Removing oil seal sleeve

CAUTION

When making a cut in the sleeve, be very careful not to
damage the crankshaft with the chisel.

Make a cut at three locations on the periphery of the oil seal
sleeve to reduce its tension. To do so, hold a chisel against
the sleeve periphery in the radial direction and strike it with
a hammer. When the sleeve is loosened, remove the sleeve.
If the sleeve can not be removed by the above procedure,
hold the chisel against the sleeve in the axial direction and
tap on it lightly to make the sleeve expand. Once the
interference between the crankshaft and sleeve is
eliminated, the sleeve can be removed easily.

Removing oil seal sleeve

Guide
P/N:30691-13100

Installer
P/N:30691-13200

Oil seal sleeve
installer set
P/N:30691-13010

Oil seal

Oil seal sleeve

INSPECTION AND REPAIR OF BASIC ENGINE

6-29

4.24 Inspecting main bearing surface

Check the inside surface of each main bearing shell for
abnormal contact, scratches, corrosion and peeling from
foreign material. Also check the outside surface of each
bearing shell which comes into contact with the crankcase
or main bearing cap for abnormal seating.

Inspecting main bearing surface

4.25 Measuring clearance between main bear­ing and crankshaft journal

(1)

Reassemble main bearings.

(2) Tighten the main bearing caps to the specified torque.
(3) Measure the inside diameter of the main bearings.
(4) Measure the outside diameter of the crank journal.
(5) Calculate the clearance between the inside diameter of

the main bearing and outside diameter of the crank
journal.

(6) Replace the main bearing if the clearance exceeds the

limit.

(7) Measure the clearance between the main bearing cap

and the crank journal again. Use the undersize bearing
if the limit is exceeded.

(8) If a n undersize bearing is used, grind the crank journal

to the specified undersize.

Measuring inside diameter of lower hole of main

bearing

Measuring crank journal outside diameter

Scratch on the inner
and outer circumference,
corrosion, and detachment

Item Standard Limit

Clearance between
main bearing and
crankshaft journal

0.050 to 0.110 mm

[0.0020 to 0.0043 in.]

0.200 mm

[0.0079 in.]

103 ± 5 N·m {10.5 ± 0.5 kgf·m}
[76 ± 3.6 lbf·ft]

Measuring
directions

Measuring
points

Measuring
direction

Measuring
position

7-1

REASSEMBLY OF BASIC ENGINE

1. Reassembling piston, connecting rod,

crankshaft and crankcase ...............7-2

1.1 Installing main bearing............................. 7-2

1.2 Installing thrust plate................................ 7-2

1.3 Installing tappet........................................ 7-2

1.4 Installing crankshaft.................................7-2

1.5 Installing main bearing caps .................... 7-3

1.6 Inserting side seal............. ... ... ... .............. 7-3

1.7 Installing main bearing cap bolt ............... 7-3

1.8 Measuring crankshaft end play................ 7-4

1.9 Reassembling piston and connecting rod 7-4

1.10 Installing piston ring................................. 7-5

1.11 Preparation for installing pistons.............. 7-5

1.12 Installing connecting rod bolt and connecting

rod bearing.... ........................................... 7-6

1.13 Installing pistons ...................................... 7-6

1.14 Installing connecting rod cap ................... 7-7

2. Reassembling timing gear and

camshaft..........................................7-8

2.1 Installing oil pump.................................... 7-8

2.2 Installing front plate.................................. 7-8

2.3 Installing camshaft gear and thrust plate.7-9

2.4 Installing camshaft................................... 7-9

2.5 Installing PTO drive gear ......................... 7-9

2.6 Installing idler gear................................. 7-10

2.7 Installing oil pump gear.......................... 7-11

2.8 Installing fuel injection pump.................. 7-11

2.9 Inspecting and adjusting timing gear after

installation.............................................. 7-11

2.9.1 Inspecting backlash and end play............7-11

2.10 Installing front oil seal ............................ 7-12

2.11 Installing timing gear case ..................... 7-12

2.12 Installing oil strainer............................... 7-12

2.13 Installing oil pan..................................... 7-13

2.14 Installing cover....................................... 7-14

2.15 Installing crankshaft pulley and damper. 7-14

3. Reassembling flywheel .................7-15

3.1 Installing oil seal..................................... 7-15

3.2 Installing rear plate................................. 7-15

3.3 Installing flywheel................................... 7-15

4. Reassembling cylinder head and valve

mechanism ...................................7-16

4.1 Cleaning cylinder head bottom surface..7-16

4.2 Installing valve stem seal....................... 7-16

4.3 Installing valve and valve spring ..... ... .... 7-16

4.4 Installing cylinder head gasket...............7-17

4.5 Installing cylinder head assembly ..........7-17

4.6 Tightening cylinder head bolts ............... 7-17

4.7 Inserting push rod ..................................7-18

4.8 Reassembling rocker shaft assembly .... 7-18

4.9 Installing rocker shaft assembly............. 7-18

4.10 Determining top dead center of No. 1 cylinder

compression stroke................................7-19

4.10.1When reusing the damper....................... 7-19

4.10.2When replacing the damper with a new

one........................................................... 7-19

4.11 Adjusting valve clearance ......................7-19

4.12 Installing rocker cover............................ 7-19

REASSEMBLY OF BASIC ENGINE

7-2

1. Reassembling piston, connecting rod, crankshaft and crankcase

1.1 Installing main bearing

CAUTION

Do not apply oil to the bearing outer surface, as the oil
may cause bearing seizure.

(1) Press the upper main bearing into position by aligning

its lug to the lug groove on the crankcase.

Note: The oil hole of the main bearing is aligned with the

oil hole of the crankcase by installing the upper main
bearing in alignment with the lug groove.

(2) Apply a small amount of engine oil to each bearing.

Installing main bearing upper

1.2 Installing thrust plate

Install the thrust plates to the crankcase outside face of
rearmost bearing and to the main bearing cap with their
grooves facing outward.

1.3 Installing tappet

Apply engine oil onto the periphery of tappets, insert them
into the tappet holes.

Installing thrust plate

1.4 Installing crankshaft

(1)

Install the wood ruff key on the crankshaft.

(2) Make sure that the main bearing upper shells that are

installed in the crankcase bores have their inner
periphery (the surface comes into contact with the
journal) lubricated with an even coat of fresh engine
oil.

(3) Wash the crankshaft thoroughly with cleaning oil and

dry it completely by blowing compressed air. Then,
apply an even coat of fresh engine oil to the crankshaft
journals.

Note: When cleaning the crankshaft, pay special attention to

the oil holes in the crank journals and crankpins, and
make sure that they are free from any foreign matter.

(4) Sling up the crankshaft horizontally, then move it above

the crankcase and lower it slowly into position.

Note: When lifting the crankshaft with a chain block, do not

attach a metal hook or similar fitting directly onto the
crankshaft. Such metal fittings can damage the
crankshaft easily. Always lift the crankshaft using
cloth belts or pads on the supporting points.

Installing crankshaft

Main bearing
upper

Align with lug groove.

Oil groove

Thrust plate, upper

Thrust plate, lower

Thrust plate, lower

REASSEMBLY OF BASIC ENGINE

7-3

1.5 Installing main bearing caps

CAUTION

The foremost and rearmost caps should be installed
so that they are flush with the crankcase surface.

Install the main bearing caps from the front side in the order
of the numbers marked on them.

(1) Apply engine oil to lower main bearings and install

them to the main bearing caps.

(2) Apply ThreeBond 1212 to the mating surface of the

foremost and rearmost caps and the crankcase mating
faces before installing the main bearing caps.

Note: Do not apply ThreeBond 1212 to any other surface

other than the mating surfaces of the foremost and
rearmost caps and the crankcase mating faces.

(3) Install the main bearing caps and temporarily tighten

bolts.

Installing main bearing cap

1.6 Inserting side seal

(1)

Apply a sealant to the outer periphery of new side seals.

(2) With the round section of the side seals facing outward,

press them partway into the front and rear caps using
hands.

(3) Wh en the side seals are installed p artway into caps, use

a tool with a flat surface to install completely, taking
care not to bend the seal.

Note: Make sure that the rear bearing cap rear face is flush

with the engine rear face.

Inserting side seal

1.7 Installing main bearing cap bolt

(1)

Tighten the main bearing cap bolts alternately and
progressively to the specified torque.

(2) Make sure that the crankshaft rotates smoothly.

Installing main bearing cap bolt

Apply ThreeBond 1212 to corner of cap

Apply ThreeBond 1211 to side seal

Sealant ThreeBond 1211

Side seal

Bearing cap

Crankcase

R section

103 ± 5 N·m
{10.5 ± 0.5 kgf·m}
[76 ± 3.6 lbf·ft]
[Wet]

REASSEMBLY OF BASIC ENGINE

7-4

1.8 Measuring crankshaft end play

Attach a dial gauge to the end of the crankshaft to measure
the end play.
If the end play deviates from the standard value, loosen the
main bearing cap bolts and retighten.
Make sure that the crankshaft turns freely.

Measuring crankshaft end play

1.9 Reassembling piston and connecting rod

(1)

Apply engine oil to the piston pin, and reassemble the
piston and the connecting rod by inserting the piston
pin, observing the orientation of piston and connecting
rod shown in the illustration.

Note: The pistons and piston pins are assembled to each

other in clearance fit. However, the piston pins are
more easily inserted into the pistons if the pistons are
warmed up with a heater or in hot water.

(2) Using ring pliers, install the snap ring. Check the snap

ring for its tension, and make sure the ring fits snugly in
the groove.

Note: Install all the snap rings so that their end gap faces

toward the bottom of the piston.

Reassembling piston and connecting rod

Installing snap ring

Item Standard Limit

Crankshaft end play

0.100 to 0.264 mm

[0.0039 to 0.0104 in.]

0.300 mm

[0.0118 in.]

View A

Front mark

Weight stamp

Matching
mark with
connecting
rod cap

A

Snap ring pliers

REASSEMBLY OF BASIC ENGINE

7-5

1.10 Installing piston ring

CAUTION

A marking is stamped near the end gap to indicate the
top face of piston ring. Install all piston rings with this
mark facing upward.
If the rings are installed upside down, it could cause
malfunctions such as excessive oil consumption or an
engine seizing.

(1) Install the piston rings to the piston with a ring

expander.

(2) Insta ll the oil ring with its end gap 180° awa y from the

joint of the coil spring, as shown in the illustration.

Piston/piston ring orientation

Reassembling oil ring

1.11 Preparation for installing pistons

(1)

Lay the engine on its side.

(2) Clean the cylinder inner surface and the crank pin with

a cloth, and apply engine oil.

Cleaning cylinder inner surface and applying engine oil

Top mark

Oil ring

No.1
compression
ring

No.2
compression
ring

Piston ring plier
P/N:31391-12900

Oil ring abutment

Coil spring butted ends

180°

REASSEMBLY OF BASIC ENGINE

7-6

1.12 Installing connecting rod bolt and connect­ing rod bearing

(1)

Press fit the connecting rod bolts into the connecting
rod.

Note: When press fitting the bolt, make sure that the bolt

fully contacts its seating position without any
interference with the shoulder of mounting surface.

(2) Install the upper connecting rod bearing with its lug

fitted in the lug groove of connecting rod.

(3) Insta ll the connecting rod bearing with its lug fitted in

the lug groove of connecting rod cap.

(4) Apply engine oil to the inner surface of bearing.

Installing connecting rod bolt and bearing upper

Installing connecting rod bearing

1.13 Installing pistons

CAUTION

Do not forcefully insert the piston, as it may cause
damage to the piston rings and crank pin.

(1) App ly engine oil to the circumference of the piston and

piston rings.

(2) Orient the ring e nd gaps diagonally o pposite eac h other

avoiding the piston pin direction and its right angle
direction.

(3) Turn the crankshaft to bring the crank pin of the

cylinder to bottom dead center.

(4) Orient the front mark on the top of piston toward engine

front.

(5) Using a piston installer, insert the piston from the top

face of crankcase into the cylinder.

Orientation of piston ring end gaps

Installing piston

Lug groove

Apply engine oil.

Lug groove

Apply engine oil.

180°

60°

60°

Oil ring end gap

Thrust position

Camshaft side

Opposite-to-thrust
position

No.2
Compression
ring end gap

No.1
Compression
ring end gap

Combustion chamber side

Front mark

Piston installer
P/N:34491-00200