Mitsubishi 4DQ50 User manual

SERVICE MANUAL
三菱ディーゼルエンジン
三菱ディーゼルエンジン
MITSUBISHI
DIESEL ENGINE
4DQ50
MITSUBISHI HEAVY INDUSTRIES, LTD.
No. 5-1, Marunouchi, 2-chom Chiyoda-ku, Tokyo Japan
Phon : Tokyo [phone] T l x: J22282, J22443 HISHIJU
SERVICE MANUAL
99609-50000
DEC 1985

MITSUBISHI DIESEL ENGINE MODEL 4DQ5OW

MITSUBISHI DIESEL ENGINE MODEL 4DQSOC

CONTENTS
PREFACE .................................................. .
CHAPTER 1 OPERATION
AND HANDLING ......................... 2
Newengine
............................................. .
2 Checkup
and preparations prior to starting ........................ .
3 Engine starting
4
After the engine's start ...................................... .
5 Engine operation
2
2
4
5
5
6 During operation .......................................... 5
7 Stopping
............................................... 6
8 Handling in cold weather
.:................................... 7
8-1 Starting in cold weather .................................. 7
8-2 General instructions
..................................... 7
9 Handling in the
hot season .................................... 8
CHAPTER 2 FUEL,
OIL AND COOLING WATER 9
1 Fuel..................................................... 9
2 Engine oil
............................................... 9
2-1 Quality required of engine oil ... . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9
2-2 Recommendable
classes of engine oil .......................... 9
2-3 Time
to change engine oil ................................. 10
3 Diaphragm oil •......•.................................... 10
4 Cooling water ............................................ 10
4-1 Required quality ...............•....................... 10
4-2 Handling of cooling system ..........•..................... 10
CHAPTER 3 REGULAR SERVICING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11
Lubrication .......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11
2 Air system .............................................. 15

2·1 Air cleaner (oil bath type) ................................. 15
2·2 Air cleaner (filter paper type) ............................... 16
2·3 Valve clearances ....................................... 18
2·4 Compression pressure .................................... 18
3 Oil system ..........................•................... 18
3·1 Oil pan ............................................. 19
3·2 Oil filter .............................•............. " 20
3·3 Differential bypass valve .................................. 20
3-4
Oil pressure .......................................... 21
4 Fuel system
............................................. 22
4·1 Fuel filter ............................................ 22
4-2 Bleeding (or priming) .................................... 24
4·3 Checkup of nozzles ..................................... 24
4·4 Fuel injection pump ....................•................ 26
4·5 Fuel injection timing .................................... ' 27
4·6 Governor (pneumatic) •.................................. 28
4·7 Governor (mechanical) ................................... 31
Governor (Model RSV, bosch type)
.•••.•••..••...•..••••.....•. 34
4-8 Automatic timer . . • • • ...•••••...•..•........•..•......•.. , 45
4-9 Measurement of engine speed ............................... 46
5 Cooling System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 48
5-1 Cooling water and radiator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 48
5-2 Thermostat........................................... 49
5-3 Tension of fan belt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 49
6 Electric system ..........•................................ 50
6·1 D.C. Generator ......................................... 51
6·2 A.C. Generator ••..•..•.. ~ . . . . . • • . • • • • • • • • • • • • • • • • . • . . . . .• 52
6·2-1 D.C. Generator Relay '" . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 53
6·2·2 A.C. GeneratorRelay . . . • • . . • • . • • • . . • • • • • • . . • • . • • . . . • • . . . •• 53
6·3 Starter .........•.......................•............ 53
6·4 Battery ............................................. 54

7 Re·screwing of main bolts .................................... 55
7·' Cylinder head clamp bolts .............................•... 56
7·2 Main bearing caps and connecting rod caps ...................... 56
7·3 Others .............................................. 56
CHAPTER 4 TROUBLE·SHooTING.................................. 59
Trouble shooting chart .•••. . • . . . . . . • • . • . • • . . . • • • • • . • • . • . . • . • • • •• 60
2 Trouble shooting chart (Appendix) •.• . • • . • • • • • . • • . • . • . . . . . . • • • . • . • . •• 64
CHAPTER 5 OVERHAULING INSTRUCTIONS ........................ 69
General instructions ........................................ 69
2 Cylinder head and valves ..................................... 70
2·' Reface of valve seats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 70
2·2 How
to replace valve guides ................................ 70
2·3 Combustion chamber
jet and director ......................... 70
2·4 Rocker shaft brackets
.......•............................ 71
3 Pistons and connecting rods . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 71
3·' How to remove and install piston and connecting rod ass'y ........... 71
3·2 How to ceuple piston with connecting rod ...................... 72
3-3 How
to remove and install piston pins ......................... 72
4 Cylinders
................................................ 73
4·' Oversizes ............................................ 73
4-2 Cylinder liners ............... . . . . . . . . . . . . . . . . . . . . . . . . .. 73
5 Bearing metals
............................................ 73
5·' General cautions ....................................... 73
5-2
How to assemble main bearing metals . _. . . . . . . . . . . . . . . . • . . . . .. 74
5-3 Undersizes ..•....•................................... 74
6 Timing gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 74
6·' Timing gear train .•..................................... 74
6·2 Valve timing .......................................... 75
7 Oil
seals ................................................ 76
8 Mountings
.............................................. 76
9 Oil
pan installing .......................................... 77

10 Oil pump .•..•........•.•............................... 77
11 Water pump .•......................•..........•.•.•..... 78
12 Bolt screwing •.......•........................•.......... 78
Model 40Q50 engine service standard ••..•••.••.•.•••...•..•.••.••• 80
IiAPTER 6 TOOLS ........................................... 100
Common tools ............................................. 100
2 Special tools ..............................•.............. 101
of APTER 7 MAIN SPECIFICATIONS AND PERFORMANCE . ............. 103
Main specifications of Mitsubishi Diesel Engine Model 40050 ............ 103
2 Performance of Mitsubishi Diesel Engine Model 40050 ................. 104
40050A (for motor vehicles) performance curve ................... 105
40050C (for construction machine) performance curve .............. 106
40050P (for general power) performance curve ...........•....... 107

PREFACE
1. In every new Model 40050 Engine, fuel injection pump and governor lever bear lead
seals
that were put after their setting upon final confirmation of its performance through
test runs,
at our factory. This service manual is intended to cover regular maintenance
services. For informations
about particular servicing, especially of sealed units and parts
such
as mentioned above, please contact our service man or your dealer.
2. Engine name plate is found on the up-side of rocker case. Engine Model and No. are
given on it.
They are also stamped on
the right.side of crankcase. They will serve as important data
to know the engine's career and make-up of components.
Fig. 0-1 Stamped engine No. Fig. 0-2 Service
meter
3. As for fuel, engine's power source, and lubricating oil to smooth engine operation,
please use those are above
OM class as shown in caution plate. Their choice has a
considerable influence on
the engine's service life. Lubrication and other servicing in
accordance with the instructions given herein will promise its most satisfactory operation.
For regular service intervals are based on the reading of service meter, don't forget to read
it every day.
At the same time, check the day's fuel and oil consumptions. The data
collected
thus every day will prove very useful to know later how the engine has been
running and
is at the time.
4.
We hope that, along with this manual, you will make use of the parts catalogue to
deepen your knowledge about the handling of your engine.
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CHAPTER 1 OPERATION AND HANDLING
1.
NEW ENGINE
Prior to putting it in use, check as follows:
1) See if there are any loose bolts or nuts.
2) Lubricate according to Lubrication Table given later.
3) -Fill fuel tank with clean fuel
and bleed (or prime) fuel system.
4) Fill radiator with clean soft water as a ccolant.
When air temperature
is expected to fall below the freezing point, use an antifreeze.
The service life of new engine much depends upon how it is handled in the initial
runs. So, lubricate, and check it with particular care (Refer
to Lubrication and Service
Tables), and before it covers 60Hr, follow the instructions given below, taking care not
to overstrain it.
1) After starting, never apply load immediately without warming it up well by idling.
2) Don't run it at high speed.
3) Run under some 70% of load at the maximum.
-2. CHECKUP AND PREPARATIONS PRIOR TO
STARTING
Prior to starting the day's operations, check as
follows with
the engine placed as level as possible.
1) Engine oil level
Pull out oil level gauge and wipe; then put it
in and
out again to check oil level. Oil level must
be above mid-point between upper "FULL" line
and lower one. If near or below
the mid·point,
refill up to upper line "FULL".
Oil level difference between these two lines
corresponds
to approx. 1 litre.
After refilling, wait for all added oil to run Fig.
1-1 Ch~king oil level
down into oil pan and for oil level to settle, before checking itagain.
2) Cooling
water level
Optimum -water level is 20'-30mm below the bottom of water inlet for pressure
type radiator, and up to overflow pipe for non-pressure type one.
Remarkable decrease of cooling water means leak somewhere, hence the necessity
to repair immediately.
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In the case of pressure type radiator, don't screw off its cap just after the engine
stopped, lest you should get burnt by outblow
of high-temperature steam.
3) Fuel
Check fuel level.
If fuel tank is equipped with fuel feed cock, make sure that it is open. At starting
after long leaving idle, or when air seems
to be in fuel system, practise bleeding (or
priming).
(Refer
to "Bleeding".)
(Mechanical governor)
'pneumatic governor)
Fig. 1-2 Around Venturi lever Fig. 1-3 Around-Stop lever
4.) Power source
Make sure that battery switch and battery terminals are on.
Now check
as follows and proceed to starting,
1) That the engine is clutched off or free from load.
2) That stop lever is not in "stop" position.
3)
That venturi lever is in "full-open" position (for pneumatic governor use)
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3. ENGINE STARTING
Model 40050 engine is equipped with either of push button or key type starting
switches.
In push button type switch, a press on button "H" keeps it on until another press
on button
"5" makes it pop out automatically.
1) Put key into starting switch.
2) Press button "H" (or turn key counterclockwise) to make glow plugs red hot.
Pre-heating time depends upon air and engine temperatures.
In any case, pre-heat
until glow plug indicator becomes red hot. Usually some 25 seconds pre-heating
will
make it red hot. If it gets red hot too early or too late, check glow plugs, for that is
an evidence of one or more of them breaking.
Fig. 1-4 Push button type
starting switch
1· Starter switch
2 Glow plug indicator
3 Engine stop
button
Fig.1-5 Key type starting switch
3) Then, press button
"5" (or turn key clockwise) to switch on starter. When the
engine
is very cold, pull stop lever at the same in opposite direction to position
"stop", and an increase of injection will make starting easier. In this case, pull it
back to "neutral" as soon as first firing.
Keep starter running until the engine has completely caught to run with a steady
rise of speed, but never any longer than 30 seconds at a time.
If starting has failed, don't switch on starter again before both starter and engine
come
to a dead stop and starter cools down. While the engine is running, don't try
to increase injection nor switch on starter.
Note: According
to specifications, Model 400 Engine is equipped with a governor
that has a built-in automatic device to increase injection. In pneumatic
governor use, prior
to starting, place stop lever once in position "stop" and pull
back
to "neutral" to assure a quick increase of injection. Particularly attempt
-4-

the same when the engine has stopped by chance.
4)
When the engine has perfectly caught, bring back Venturi lever (or control lever)
immediately to "idling".
For starting in winter, Refer to "Cold starting".
,
4 AFTER THE ENGINE S START
Keep it idling
at medium speed for some 5 minutes for warm~up, then start driving or
operations. This
will prove very effective in protecting moving parts from wear and in other
aspects. With the engine idling, check
as follows:
1) Anything unusual with ~iI pressure? (Refer to Par. 3-4, "Oil pressure", Chap. 3,
"RegularServicing".)
2) Does the engine make unusual noise?
3)
Is exhaust colour abnormal?
4) Any leak of water, fuel
or oil?
5 . ENGINE OPERATION
Model 4DQ50 engine is equipped with a pneumatic governor or a mechanical governor
for each use. This governor being of the all·speed governing type, variation of engine speed
depends upon how far Venturi unit
is opened for in which position control lever is. This
design
is such that, at a certain degree of Venturi unit opening or control lever position
engine
output is automatically governed with changes of load so as to keep engine speed
almost constant.
During operation, leave stop lever
in "neutral". (pneumatic governer 'use)
For details, refer to Par. 4-6, "Governor"
6 DURING OPERATION
After warm·up run, apply load on the engine.
During operation, judge how the engine
is going, from ~e indications of meters, sound,
exhaust colour and etc.
1) Oil pressure (Refer to Par. 3-4, "Oil pressure".)
Oil pressure gauge, if the engine is equipped with one, must read 3-4kg/cm
2
(2kg/cm2 at minimum) at usual engine speed and above 0.5kg/crn2 in idling. If oil
pressure alarm lamp attached, watch it every now and then. If it should get alight, check
oil system.
2) Water temperature
Optimum range
is 75°-85°C. Overheating arises from lack qf cooling water, loose
-
5-

fan belts and poor functioning of thermostat. In case the engine gets overcooled, put a
suitable cover on radiator.
3) 'Generatorcharge
While generator
is charging batteries, ammeter pointer indicates (+) scale. At the
beginning of charging, it indicates about 10A, then gradually decreases
as batteries get
charged.
So you must not take this aspect for any generator trouble.
Charge pilot lamp, which
is attached at option, goes out when the engine has
started and generator begins to charge. If a rise of engine speed should not put it off,
check and service
charg'ing system immediately. If the system left defective, batteries
will entirely run down, making engine starting absolutely impossible.
7 STOPPING
After the operations over, let the engine idling for some 5 minutes. Don't bring it to a
sudden stop with its parts heated hot.
As letting it idling, pull back
st:>p lever to position "stop", and fuel injection will be cut
off and thethe engine come to a stop.
When the engine has come to a dead stop, pull back stop lever to "neutral". Remember
that, if the lever released when the engine has not yet stopped, it may run reverse.
Note: Reverse running
of the engine
Model 4oQ50 engine may happen, though rarely, to run reverse in the following cases.
1) When, in an attempt to cut off injection by pulling back stop lever, the lever is
released, before the engine comes to a dead stop.
2) When starting motor is switched on with batteries not charged enough to power it
as required
to start the engine.
Reverse running can
be readily noticed, as the engine emits then much black smoke
through air cleaner, making noise
at the same time. But it will rather hard to stop in
the usual way, for exhaust pressure will then' press govemor diaphragm so tight to
"full injection" pOSition as not to permit stop lever be easily pulled back.
So take any of the following emergency measures to stop it.
1) Bring accelerator button to "full-open" position and force back stop lever.
2) Increase load to maximum to bring the engine to stop. (Apply brakes, if
available.)
3) Shut exhaust pipe by hand or with waste cloth.
Keep
in mind that long reverse running will make oil pump run reverse, too, and as
the result, metals will get burntfrom the stop of oil circulation.
-6-

8 HANDLING IN COLD WEATHER
When the air temperature is very low and the engine is cold, engine starting is
confronted with such factors as low temperature of intake air which disturbs the rise of
compression temperature,
an increase of oil viscosity and a drop battery voltage which keeps
starter from developing enough power
to drive the engine. In addition, cooling water and
battery electrolyte may freeze up. For starting and handling
in cold weather, follow the
special instructions given below.
8-1 Starting in cold weather
Proceed according
to the following additional hints so that a single attempt will
make success in starting. Repeated use of starter will discharge batteries.
1) Put the engine as free from load as possible. If clutch attached, disengage it,
besides shifting transmission gear into neutral.
2) Pre-heat well by electrifying glow plugs for 30-40 seconds, so as to permit
ready ignition.
If starting has failed, don't switch on starter again without
pre-heating.
3) The moment first firing takes place, bring back lever
to neutral. Further
increase of fuel feed
will cool combustion chamber, hence a lag in perfect
firing.
4) Even when initial ignition has taken place and .been followed by imperfect
combustion, keep starter running until the engine perfectly catches to gather
speed, so
that glow plugs will remain red hot to help perfect firing. Starter has
a free wheel, which protects it against any damage even when its pinion
is kept
in mesh with ring gear in that way. In any case, don't run it any longer than 30
seconds at a time.
8-2 General instructions
1) Unless an antifreeze is mixed in cooling water, drain it off entirely after the
operations over, lest it should freeze up
to damages cylinder block, cylinder
heads, radiator, etc.
Use of an antifreeze dispenses with the trouble of draining.
Choose a reliable brand of antifreeze
that contains a suitable proportion of
anticorrosive, and mix it according
to the manufacturer's instructions given on
the can, for its proportion usually depends upon the lowest temperature
expected. Quantity of cooling water for 4DQ50W
is 10 litres and 40Q50C is
16 litres. (with standard radiator)
2) In winter, use engine oil of lower viscosity. (Refer to Chap. 2, "Engine Oil".)
3) Existence of water in fuel will cause some trouble with fuel system from
-7-

freezing of pipes. So bleed (or prime), fuel tank, fuel filter, etc.
4)
At low temperature, battery capacity goes down, hence batteries should be
covered with a tarpaulin sheet, or be stored in a warm place when not needed.
Keep
the specific gravity of battery electrolyte'above 1.25 so as to prevent it
from freezing. (Refer
to Par. 6-4, "Batteries" Chap. 3).
5) Warm up the engine well, and never overstrain it.
During operation, watch thermogauge and if it
gives any sign of overcooling,
put a cover on radiator.
9 HANDLING IN THE HOT SEASON
1) Use engine oil intended for summer. (Refer to Chap. 2, "Engine Oil".)
2) Keep the tension of fan belts properly adjusted so as to allow them a slack of
12mm. (Refer
to Par. 5-3 "Tension of fan belt" Chap. 3) Watch thermogauge, too.
When cooling water has started boiling from overheat, Don't stop the engine
at
once, but let it idling for a time, Waiting for water temperature to fall.
3) Check battery electrolyte level every day and if lower than specified, add distilled
water.
4) When the engine
is to be left idle under high temperature for several days or longer,
store batteries
in a cool dark place to prevent their self-discharge.
- 8-

CHAPTER 2 FUEL, OIL AND COOLING WATER
1 FUEL
1) For fuel, use gas oil (with greater cetane number than 45) of a well-known and
reliable brand and destined for high"speed
Diesel engines.
2) Use of clean fuel is of greatest importance for the fuel system of a Diesel. Dust and
water
in fuel do damage to precisionmachined injection pump, nozzles, etc. In
filling fuel tank, take care not to let in any bit of dust and water. The refilling of
fuel tank should be done after the operations are over. At regular intervals, open
drain cock on fuel tank
to draw off settled water and dirt prior to starting, and
wash its interior.
2 ENGINE OIL
2-1 Quality required of engine oil
A high-speed Diesel requires for its lubrication better-quality mineral oil than that
intended for ordinary gasoline engines.
It means that such oil satisfies the following requirements.
1) To be stable against heat and oxidation.
By high heat of cylinders, oil is subject to oxidate and carbonize, and
cor.sequential collection of carbon and residues leads
to wear and seizure.
Therefore,
oil needs to contain at least two kinds of additives to improve its
stability; an anticorrosive and a detergent
that dissolves carbon and sludge in
oil and thus washers them away.
From these view-points, use always
H.D. type that contains both, so is very
favourable for the service life of pistons, liners,
rings and metals, etc.
2) To have high viscosity stability against changes of temperature.
For easy starting
at low temperature, oil is required to be low in viscosity but,
after starting, be high enough
to assure perfect oil film on high~temperature
parts. Practically, however, a single oil cannot opportunity satisfy these
requirements, so it follows
that an oil whose viscosity is less subject to change
should be used.
2-2 Recommendable classes
of engine oil
In view of the foregoing requirements, DM class in A.P.I.'s service classification
should be chosen.
As for viscosity selection, consult the following table.
-9-

Climates Above 40°C 40°
-_5°C _5° -_15°C
Below-15°C
Viscosity SAE #40 SAE #30
SAE #20
SAE#1aw
Except in an frigid region, SAE 30 can be applied throughout the year.
2-3 Time to change engine oil
Time to change engine oil is indicated as a general standard in Lubrication Table. It
may, however, get dirty and deteriorate very soon and need to be changed much ahead
of the given time, under some conditions of use, and be very show to do so under
others.
Practically speaking, the user himself should judge whether it can stand further
use
or must be changed. For this, we recommend a simple test called "spot test", where
some drops of used engine
oil are put on filter paper to see how far it has deteriorated
and got dirty. For details about this test, ask the manufacturer
of the oil.
3 DIAPHRAGM OIL (Pneumatic Governor)
Diaphragm oil is a kind of leather oil intended to prevent the aging or deterioration of
sheep
skin diaphragm placed in pneumatic governor of fuel injection pump, and to keep
governor action smooth and sensitive.
Use always those brands indicated on· Lubrication
Table, and never substitute by engine
oil (mineral oil).
4 COOLING WATER
4-1 Required quality
Cooling water must be clean and soft. Never use any water that contains salt or is
near a mine or a spa, because it will scale hard water jacket and corrode cylinder liners
along their outercircumference.
4-2 Handling of cooling system
1) In leaving the engine idle for many hours, especially in cold weather, open all
drain cocks to thoroughly drain off cooling water.
2) When the engine has overheated and has been empty of water, never pour cold
water
in radiator.
3) For the use of an antifreeze, refer to Sect. 8, "Handling in Cold Weather"
Chap. 1.
- 10-

CHAPTER 3 REGULAR SERViCING
To service your engine regularly is the key to enjoy its ever trouble-free and efficient
operation and long service.
To say nothing of usual services before and after the work, appropriate measures must
be taken if, during operation, any unusual symptons in sound, exhaust colour, smell, etc.
should
be noticed.
In this chapter are given in detail the necessary instructions for regular checkup and
servicing, starting with lubrication, along with the constructional descriptions of engine
parts. Standard intervals are based on the reading of service meter. For any
ch&ckup and
servicing, place the engine
as level as possible.
1 LUBR ICATION
This section covers the points of lubrication, which is a basic factor of maintenance. It is
most desirable to use the classes of oils recommended in the preceeding chapter.
'j) Engine oil pan Checkup of oil level:
1 Drain plug
Fig. 3-1 Checking oil level
Fig. 3·2 Drain plug on oil pan
Check
it every morning or prior to starting.
Checking procedure
is described in Sect. 2, "Checkup and Preparations prior to
Starting", Chap. 1.
Change of engine oil:
Every 250Hr
of run, or when bypass alarm has got alight, change oil. In new engine,
change it after initial 60 Hr
of run.
For complete change
of used oil, drain it off, screwing off drain plug on oil pan
while it
is still hot, i.e., a little after the engine stopped. At the same time, empty oil
-11-

filter and oil cooler (if attached) too, and replace oil filter elements.
When used oil has all drained off, pour
in the specified quantity of new oil through
oil filler on the side of crankcase.
or rock.er case cover, let the engine run at idling for
several minutes, and stop it and check
oil level with level gauge.
Note: Standard quantities of
oil for·400SOW is 4.7 litres.
40OSOC is 6.0 litres.
400S0P (without oil cooler) is 6.7Iittes.
2) Fuel.injection pump cam case
Chockup
of Oil level:
Every 120Hr of run, pull
oil level gauge (1) out of injection pump cam case and
check oil
level. If it tells a decrease of oil. Check and repair the leak. Standard oil level is
up to the mark line cut on the gauge.
1. filter element 3. Head
2. Coyer
Fig_ 3-3 Replacing oil filter element Fig. 3-4a Lubrication
of fuel injection pump
(pneumatic governor)
Fig. 3-4'b Lubrication
of fuel injection pump
(mechanical governor)
-
12-