Mitsubishi S6S Service Manual

Service Manual

99709-56120

For use with FD40K, FD40KL, FD45K, FD50K,
FD60, FD70, Chassis Service Manual.

S6S Diesel Engine

28620-up

FOREWORD

This service manual covers S6S Diesel Engine of Mitsubishi Forklift Trucks and gives detailed
maintenance and repair information. The instructions are grouped by systems to serve the
convenience of your ready reference.

Long productive life of your forklift trucks depends to a great extent on correct servicing – the
servicing consistent with what you will learn from this service manual. We hope you read the
respective sections of this manual carefully and know all the components you will work on
before attempting any work.

All descriptions, illustration, specifications, and serial numbers in this manual are effective as
of the printing date of this manual. Mitsubishi reserves the right to change specifications or
design without notice and without incurring obligation.

Pub. No. 99709-56120

How to Use This Manual

This service manual contains the S6S Diesel Engine specifications, maintenance standards and adjustment
procedures as well as service procedures such as disassembly, inspection, repair and reassembly are arranged in
groups for quick reference.

There are separate manuals for the fuel injection pump and governor.

A short summary of each Group is given in the General Contents, and there is also a table of contents at the
beginning of each Group.

Regarding engine operation and periodical maintenance, refer to the Operation & Maintenance Manual. For
component parts and ordering of service parts, refer to the Parts Catalogue. Structure and function of the engine are
described in various training manuals.

1. Methods of Indication

(1) Parts shown in illustrations and described in text are numbered to correspond with the sequence of disassembly.

(2) Inspections to be conducted during disassembly are indicated in a box in disassembled views.

(3) Maintenance standards for inspection and repair are described in text where they are relevant, are also listed in

Group 2 in the General Contents.

(4) The sequence in which parts are to be assembled is summarized below each assembled view.

Such as:

52431

(5) The following marks are used in this manual to emphasize important safety cautions.

…Indicates a potentially hazardous situation which, if not avoided, could result in death or

serious injury.

…Indicates a potentially hazardous situation which, if not avoided, may result in minor or

moderate injury.

…Indicates important information or information which is useful for engine operation or

maintenance.

(6) Tightening torque under wet conditions is indicated by “[Wet].” When so indicated, apply engine oil to the

threaded portion of the fastener. Unless indicated as such, the tightening torque is to be assumed in the dry
condition.

←←←←

WARNING

CAUTION

NOTE

2. Terms Used in This Manual

Nominal value: Indicates the standard dimension of a part to be measured.

Standard: Indicates the dimension of a part, the clearance between parts, or the standard performance. Since the

value is indicated in a range needed for inspection, it is different from the design value.

Limit: A part must be repaired or replaced with a new part when it reaches the limit value.

3. Abbreviations, Standards, Etc.

• BTDC = Before Top Dead Center

• ATDC = After Top Dead Center

• BBDC = Before Bottom Dead Center

• ABDC = After Bottom Dead Center

• TIR = Total Indicated Reading

• 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.)

• MSDS = Material Safety Data Sheet

• SAE = Society of Automotive Engineers (U.S.)

4. 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/cm

2

• 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

2

O (cmAq)

• Rotational speed: 1 min

−

1

= 1 rpm

GROUP INDEX Items

1

2

3

4

5

6

7

8

9

10

11

12

13

GROUP INDEX

GENERAL

Outline, Specifications, Tips on Disassembly and Reassembly

MAINTENANCE STANDARDS

Maintenance Standards Table, Tightening Torques, Sealants and Lubricants,
Regarding Submission of Parts for EPA Exhaust Gas Regulation

SPECIAL TOOLS

Special Tools

OVERHAUL INSTRUCTIONS

Determination of Overhaul Timing, Testing the Compression Pressure

ADJUSTMENTS, BENCH TEST,
PERFORMANCE TESTS

Adjustments, Bench Testing, Performance Tests

ENGINE AUXILIARIES
REMOVAL AND INSTALLATION

Preparation, Engine Auxiliaries Removal, Engine Auxiliaries Installation

ENGINE MAIN PARTS

Cylinder Head and Valve Mechanism, Flywheel, Damper, Timing Gears and
Camshaft, Piston, Connecting Rods, Crankshaft, Crankcase and Tappets

INLET AND EXHAUST SYSTEM

Description, Exhaust Manifold

LUBRICATION SYSTEM

Description, Oil Pump, Oil Filter, Oil Pressure Relief Valve

COOLING SYSTEM

Description, Water Pump and Thermostat

FUEL SYSTEM

Description, Fuel Filter (Paper-Element Cartridge Type), Injection Nozzles

ELECTRICAL SYSTEM

Starter, Alternator, Glow Plug, Stop Solenoid

WORKSHOP TIPS

Basic Recommended Assembly Procedures

1. Outline ................................................................................................. 1 – 1

1.1 External View .................................................................................. 1 – 1

1.2 Engine Serial Number Location ...................................................... 1 – 2

2. Specifications .................................................................................... 1 – 3

3. Tips on Disassembly and Reassembly ....................................... 1 – 5

3.1 Disassembly.................................................................................... 1 – 5

3.2 Reassembly ................................................................................... 1 – 5

1

GENERAL

1-1

GENERAL

1. Outline

1.1 External View

Remark: Direction of rotation of this engine is counterclockwise as seen from flywheel side.

Fuel injection pump

Fuel filter

Water pump

Front Rear

Fuel feed pump

Relief valve

Stop solenoid

Oil drain plug

Left View

Oil level gauge

Oil pan

Fuel injection nozzle

Inlet manifold

Water drain plug

Flywheel

Oil filter

Exhaust manifold

Alternator

V-belt

Rear Front

Starter

Oil pressure switch

Right View

1-2

GENERAL

1.2 Engine Serial Number Location

The engine serial number is located on the side of the
crankcase.

Engine serial number location

Engine serial
number

2. Specifications

Model designation S6S

Type Water-cooled, 4-stroke cycle

No. of cylinders – arrangement 6 –in line

Combustion chamber type Swirl chamber

Valve mechanism Overhead

Cylinder bore × stroke mm (in.) 94 × 120 (3.70 × 4.72)

Piston displacement liter (cu in.) 4.996 (305)

Compression ratio 22 : 1

Firing order 1 – 5 – 3 – 6 – 2– 4

Direction of rotation Counterclockwise as viewed from flywheel side

Overall length

866 (34.1)

mm (in.)

Dimension

Overall width

622 (24.5)

mm (in.)

Overall height

801 (31.5)

mm (in.)

Weight (dry) kg (lb) Approx. 340 (750)

Type of cylinder sleeve Integral with cylinder block

No. of piston ring

Compression ring 2

Oil ring 1 (w/spring expander)

Inlet valve

Open BTDC 30°

Close ABDC 50°

Valve timing

Exhaust valve

Open BBDC 74°

Close ATDC 30°

Starting system Electric-starter

Starting aid Glow plug

Type Force feed by oil pump

API Service Classification CD or higher

Engine oil Refill capacity

Whole system: Approx. 13.0 (3.4)

liter (U.S. gal.)

Type Trochoid

Speed ratio to crankshaft 0.74

Oil pump

Capacity 38.7 (10.2) at 0.3 MPa (3 kgf/cm

2

) [42.7 psi]

liter (U.S gal.)/min discharge pressure of pump running at 2230 min

-1

Oil pressure

Type Piston valve

relief valve

Opening pressure

0.35±0.05 (3.5±0.5) [50±7]

MPa (kgf/cm

2

) [psi]

Oil filter Type Cartridge of paper element

1-3

GENERAL

General

Engine main
parts

Lubrication
system

1-4

GENERAL

Model designation S6S

Refill capacity (engine water jacket)

9.0 (2.4)

liter (U.S. gal.)

Type Centrifugal

Water pump

Speed ration to crankshaft 1.3

Capacity 160 (42.3) at 0.07 MPa (7.5 kgf/cm

2

) [107 psi]

liter (U.S gal.)/min/min

-1

discharge pressure of pump running at 3600 min

-1

Belt Type mm (in.) Low-edge B type V-belt × 1 1190 (46.9)

Type Wax pellet

Thermostat

Valve opening temperature

76.5±1.5 (170±2.7)

°C (°F)

Type Bosch A

Diameter of plunger

7 (0.276)

Injection pump mm (in.)

Cam lobe lift

8 (0.315)

mm (in.)

Governor Type Bosch RSV, centrifugal

Type of nozzle Bosch hole

No. of discharge orifice 1

Diameter of discharge

1.0 (0.039)

Injection nozzle

orifice mm (in.)

Spray cone angle 0°

Valve opening pressure

11.77 (120) [1707]

MPa (kgf/cm

2

) [psi]

Fuel filter Type Cartridge of paper element

Voltage – polarity 24 V – (−) ground

Model M008T60372

Type Pinion shift

Starter Output V – kW 24 – 5

No. of pinion teeth/

10/122

flywheel ring gear teeth

Type 3-phase, with rectifier

Output V – A 24 – 35

Working speed min

-1

8000

Alternator

Rated output generating

5000

speed min

-1

Maximum permissible

10,000

speed min

-1

Speed ratio to crankshaft 2.0

Type Electric

Glow plug

Rated voltage – current

22 – 4.4 (1.5 sec rating)

V– A

Stop solenoid Rated voltage V 24

Electrical
system

Cooling system

Fuel system