JCB 672 Mechanical Engine Service Repair Manual Instant Download

1
Foreword
SERVICE MANUAL JCB 672 Mechanical
Engine EN - 9806/6900 - ISSUE 3 -
2016-08-22 This manual contains
original instructions, verified by the
manufacturer (or their authorized
representative). Copyright 6-08-22 JCB
SERVICE All rights reserved. No part of this
publication may be reproduced, stored in a
retrieval system, or transmitted in any form or
by any other means, electronic, mechanical,
photocopying or otherwise, without prior
permission from JCB SERVICE. www.jcb.com
The Operator's Manual
You and others can be killed or seriously injured
if you operate or maintain the machine without
first studying the Operator's Manual. You must
understand and follow the instructions in the
Operator's Manual. If you do not understand
anything, ask your employer or JCB dealer to
explain it.
Do not operate the machine without an Operator's
Manual, or if there is anything on the machine
you do not understand.
Treat the Operator's Manual as part of the
machine. Keep it clean and in good condition.
Replace the Operator's Manual immediately if it
is lost, damaged or becomes unreadable.
Contents 01 - Machine
06 - Body and Framework
09 - Operator Station
15 - Engine
18 - Fuel and Exhaust System
21 - Cooling System
33 - Electrical System 72 - Fasteners and Fixings
75 - Consumable Products
78 - After Sales
2
15 - Engine 00 - General 00 - General
00 - General
Introduction
Introduction .....................................
................. 15-3 Health and Safety
...........................................
15-7 Technical Data ..............................
................... 15-8 Component Identification
................................. 15-9 Operation
..................................................
..... 15-14 Fault-Finding ........................
.......................... 15-17 Drain and Fill
.................................................
15-26 Clean ......................................
....................... 15-26 Check (Pressure)
..........................................
15-28 Remove and Install .........................
.............. 15-30 Store and Recommission
.............................. 15-34
Basic Description The 6 cylinder mechanical
engine has fuel ignited by compression ignition
(C.I.). The engine operates on a four stroke
cycle. The engine is started by an electric
starter motor. The starter motor turns the
engine via a pinion and teeth on the engine
flywheel, refer to (PIL 09-75). When the engine
runs the crankshaft drives the camshaft via
gears. The camshaft opens and closes the inlet
and exhaust valves and via push rods in time
with the four stroke cycle. The engine has 24
valves, 2 inlet and 2 exhaust valves for each
cylinder. The crankshaft also drives a
mechanical fuel injection pump via gears. The
pump injects fuel via injectors, or atomisers
into each cylinder in time with the four stroke
cycle. The pump injects fuel via injectors, or
atomisers into each cylinder in time with the
four stroke cycle. The pump is part of the
mechanically actuated fuel injection system,
refer to (PIL 18-00). Air is drawn into the
engine, via the inlet manifold and exhaust gases
exit via the exhaust manifold. The engine uses a
turbocharger which pressurises the air at the
inlet manifold, refer to (PIL 18-36). A
mechanical lubrication oil pump is driven by the
crankshaft via gears. The pump pressurises and
circulates oil for engine lubrication and cooling
purposes. A drive belt driven by the
crankshaft, drives a coolant circulation pump,
alternator, radiator cooling fan and other
ancillaries such as an air conditioning
compressor.
9806/6900-3
15 - 10
3
15 - Engine 00 - General 00 - General
Figure 3.
1 Flywheel 3 Camshaft 5 Exhaust valves (12 off) 7
Turbocharger
2 Crankshaft 4 Inlet valves (12 off) 6 Push rods
(12 off) 8 Lubrication oil pump
9806/6900-3
15 - 10
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15 - Engine 00 - General 00 - General
Internal The following identifies the main
internal components of a typical engine
assembly. Some variants may differ in detail.
As viewed on the right hand side. Refer to Figure
4.
Figure 4.
1 Rocker assembly 2 Valve bridge piece (12 off)
3 Valve bridge piece (12 off) 4 Inlet valve (12 off)
5 Exhaust valve (12 off) 6 Piston assembly (6 off)
7 Connecting rod assembly (6 off) 8 Crankshaft
9 Main bearing - crankshaft (7 off) 10 Big end bearing - crankshaft/connecting rod (6
off)
11 Front crankshaft oil seal (not shown) 12 Flywheel
6
15 - Engine 00 - General 00 - General
6a Piston ring - top compression (6
off) 6c Piston ring - oil control (6 off) 6d
Gudgeon pin circlip (12 off)
6b Piston ring - 2nd compression (6 off) 6d
Gudgeon pin (6 off)
As viewed on the rear left side. Refer to Figure
5. Figure 5.
Flywheel Fuel injector (atomiser) (6 off) 1a 3 Flywheel - crankshaft fixing bolts (8 off) Camshaft drive gear
4 Lubrication oil pump 5 Camshaft
6 Tappet (12 off) 7 Push rod (12 off)
8 Flywheel hub
7
15 - Engine 00 - General 00 - General
Health and Safety Hot Components Touching hot
surfaces can burn skin. The engine and machine
components will be hot after the unit has been
running. Allow the engine and components to cool
before servicing the unit. Turning the Engine Do
not try to turn the engine by pulling the fan or
fan belt. This could cause injury or premature
component failure. Notice The engine and other
components could be damaged by high pressure
washing systems. Special precautions must be
taken if the machine is to be washed using a
high pressure system.Make sure that the
alternator, starter motor and any other
electrical components are shielded and not
directly cleaned by the high pressure cleaning
system. Do not aim the water jet directly at
bearings, oil seals or the engine air induction
system. WARNING! To bleed the injectors you must
turn the engine. When the engine is turning,
there are parts rotating in the engine
compartment.Before starting this job make sure
that you have no loose clothing (cuffs, ties
etc) which could get caught in rotating
parts.When the engine is turning, keep clear of
rotating parts. Notice Clean the engine before
you start engine maintenance. Obey the correct
procedures. Contamination of the fuel system
will cause damage and possible failure of the
engine. Notice Do not exceed the correct level
of engine oil in the sump. If there is too much
engine oil, the excess must be drained to the
correct level. An excess of engine oil could
cause the engine speed to increase rapidly
without control. WARNING! The engine has exposed
rotating parts. Switch off the engine before
working in the engine compartment. Do not use
the machine with the engine cover open. WARNING!
Hot oil and engine components can burn you. Make
sure the engine is cool before doing this
job.Used engine crankcase lubricants contain
harmful contaminants. In laboratory tests it was
shown that used engine oils can cause skin
cancer. Notice A drive belt that is loose can
cause damage to itself and/or other engine
parts. WARNING! Do not open the high pressure
fuel system with the engine running. Engine
operation causes high fuel pressure. High
pressure fuel spray can cause serious injury or
death. CAUTION! It is illegal to pollute drains,
sewers or the ground. Clean up all spilt fluids
and/or lubricants.Used fluids and/or lubricants,
filters and contaminated materials must be
disposed of in
accordance with local regulations. Use authorised
waste disposal sites.
8
15 - Engine 00 - General 00 - General
Technical Data Table 5. Basic Engine Data
(Dieselmax 672 Mechanical Engine)
Engine EC - 6 Cylinder Mechanical, Turbocharged with Intercooler
Emission compliance Non-emission
Rated speed 1800 rpm
Weight (Dry) 680 kg (1500 lb)(1)
Number of cylinders 6
Nominal bore size 106 mm (4.173 in)
Stroke 135 mm (5.314 in)
Cylinder arrangement In line
Combustion Cycle 4-stroke
Firing order 1-5-3-6-2-4
Displacement 7.148 litres
Compression ratio 181
Engine Compression see note(2)
Direction of rotation (viewed from front crankshaft pulley end) Clockwise
Valves 4 per cylinder
Valve clearances measured at the tappet end of the rockers (measured cold) see note(2)
- Inlet 0.280.34mm
- Exhaust 0.430.5mm
Lubricating oil pressure(3) 1.6 - 6.5 bar (23 - 91lb in2)
Combustion system Direct injection, mechanical fuel injection
High pressure fuel pump Mechanical inline

1. Dry weight. No cooling fan drive.
2. Compression variance between each cylinder should
   be no greater than 3.5 bar (50 lb in2).
3. Dependent on engine temperature and speed.

9
15 - Engine 00 - General 00 - General
Component Identification 6 Cylinder Mechanical
Engine The following identifies the main
components of a typical engine assembly visible
from the exterior. Some variants may differ in
detail. Figure 6. Left hand Side
L
A
K
B
C D
J
E
H
G
F
A Lubrication oil dipstick C Lubrication oil
filler cap E Torsional vibration damper G
Bedplate housing
B Fuel injectors and high pressure fuel pipes D
Rocker cover F Lubrication oil sump H Oil cooler
housing with ports for remote oil filter
10
15 - Engine 00 - General 00 - General
J Fuel injection pump L Lifting eye head
K High pressure fuel pipes
Figure 7. Right hand side E
N F
A K
B
G
H J
C
L
M
D
p
A Timing gear case C Bedplate housing E
Turbocharger G Alternator J Coolant
inlet/radiator hose connector
B Flywheel housing D Lubrication oil sump F
Exhaust manifold H Coolant pump housing
(crankcase) K Heavy duty PTO (Power Take-Off)
(blanking cover if no device is installed) M
Turbocharger oil drain line P Oil drain plug
(sump)
L Starter motor assembly N Turbocharger oil feed
line
11
15 - Engine 00 - General 00 - General
Figure 8. Crankshaft pulley (front) end
A
L
K
C
B
G
J
H
D
F
E
A Rocker cover C Crankcase E Lubrication oil
sump G FEAD (Front End Accessory Drive)
tensioner J Alternator and drive pulley
assembly L Turbocharger
B Cylinder head D Bedplate F Torsional vibration
damper H Starter motor K Twin thermostat
12
15 - Engine 00 - General 00 - General
Figure 9. Flywheel (rear) end
G A
F
B E
D
C
A Rocker cover C Flywheel E Timing case G
Turbocharger
B Cylinder head D Fuel injection pump gear access
cover F Inlet manifold
13
15 - Engine 00 - General 00 - General
Figure 10. 6 Cylinder mechanical engine (ISO)
view M
A
L
B
C
D
H
K
E
J
F
G
A Inlet manifold C FEAD belt tensioner E Coolant
pump drive pulley G Oil drain plug (sump) J
Water inlet connector L Turbocharger J Coolant
inlet connector
B Oil cooler remote D Torsional vibration
damper F Lubrication oil sump H Starter motor
assembly K Alternator and drive pulley assembly M
Fuel injector cover
14
15 - Engine 00 - General 00 - General
Operation
The Four Stroke Cycle This section describes the
cycle sequence, for the 6 cylinders of the
diesel engine.
The stages in the four stroke cycle for each
cylinder are as follows
Table 6. The Four Stroke Cycle
Stage number Piston operation Valve operation
1 The piston is at the top of its Com- pression stroke and is about to start its Power stroke. Inlet and exhaust valves closed.
2 The piston is at the bottom of its Power stroke and is about to start its Exhaust stroke. Inlet valves closed, exhaust valves about to open.
3 The piston is at the bottom of its In- duction stroke and is about to start its Compression stroke. Exhaust valves closed, inlet valves about to close.
4 The piston is at the top of its Ex- haust stroke and is about to start its Induction stroke. Valve operation exhaust valves about to close, inlet valves about to open.
Firing order A cylinder is said to be firing,
when the fuel/air mixture ignites and the piston
is about to start its power stroke.
Power The piston continues to rise after the
start of fuel injection causing a further
increase in pressure and temperature.
The temperature rises to a point at which the
fuel/air mixture ignites. A cylinder is said to
be firing, when the fuel/air mixture ignites.
Four Stroke Cycle
Induction As the piston travels down the
cylinder, it draws filtered air at atmospheric
pressure and ambient temperature through an air
filter and inlet valves into the cylinder.
This combustion causes a very rapid rise in both
temperature and pressure. The high pressure
generated propels the piston downward turning the
crankshaft and producing energy.
Exhaust Once the piston has reached the bottom of
its travel, the exhaust valves open and momentum
stored in the flywheel forces the piston up the
cylinder expelling the exhaust gases. In a
running engine these four phases are
continuously repeated. Each stroke is half a
revolution of the crankshaft, thus, in one cycle
of a four stroke engine, the crankshaft revolves
twice.
Compression When the piston reaches the bottom of
its stroke the inlet valves close. The piston
then starts to rise up the cylinder compressing
the air trapped in the cylinder. This causes the
temperature and pressure of the air to rise.
Fuel is injected into the cylinder when the
piston is near to top dead centre.
15
15 - Engine 00 - General 00 - General
Figure 11.
3
2
C
B
4
1
746030
1 Induction 2 Compression stroke
3 Power stroke 4 Exhaust stroke
A Camshaft B Camshaft lobe - Inlet valve operation
C Camshaft lobe - Exhaust valve operation BDC Bottom dead centre
TDC TDC (Top Dead Centre)
16
15 - Engine 00 - General 00 - General
Figure 12.
717620
1
2
3
4
B
C
A
A
A
A
B C
B
C
B
C
1 Induction stroke 3 Power stroke A Camshaft C
Camshaft lobe - Exhaust valve operation
2 Compression stroke 4 Exhaust stroke B Camshaft
lobe - Inlet valve operation
17
15 - Engine 00 - General 00 - General
Clean Notice Clean the engine before you start
engine maintenance. Obey the correct procedures.
Contamination of the fuel system will cause
damage and possible failure of the
engine. Notice The engine and other components
could be damaged by high pressure washing
systems. Special precautions must be taken if
the machine is to be washed using a high
pressure system. Make sure that the alternator,
starter motor and any other electrical
components are shielded and not directly cleaned
by the high pressure cleaning system. Do not aim
the water jet directly at bearings, oil seals or
the engine air induction system.
Drain and Fill
Refer to Engine, Oil Filter, (PIL 15-21-00).

• Before carrying out any service procedures that
  require components to be removed, the engine must
  be properly cleaned.
• Cleaning must be carried out either in the area
  of components to be removed or, in the case of
  major work, or work on the fuel system, the
  whole engine and surrounding machine must be
  cleaned.
• Stop the engine and allow it to cool for at least
  one hour. DO NOT attempt to clean any part of
  the engine while it is running.
• Make sure that the electrical system is isolated.
• Make sure that all electrical connectors are
  correctly coupled. If connectors are open fit the
  correct caps or seal with water proof tape.
• Cover the alternator with a plastic bag to
  prevent water ingress.
• Seal the engine air intake, exhaust and breather
  system.
• Make sure that the oil filler caps and dipstick
  are correctly installed.
• Use a low pressure water jet and soft bristle
  brush to soak off caked mud or dirt.
• Apply an approved cleaning and degreasing agent
  with a brush. Obey the manufacturers
  instructions.
• Use a pressure washer to remove the soft dirt
  and oil. Important DO NOT aim the water jet
  directly at oil seals or electrical and
  alternator. DO NOT place the jet nozzle closer
  than 600mm (24 in) to any part of the engine.
• When the pressure washing is complete move the
  machine away from the wash area, or
  alternatively, clean away the material washed
  from the machine.

9806/6900-3
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18
15 - Engine 00 - General 00 - General

• Before working on specific areas of the engine
  use a compressed air jet to dry off any moisture.
  When the area is dry use a soft clean brush to
  remove any sand or grit particles that remain.
• When removing components be aware of any dirt or
  debris that may be exposed. Cover any open ports
  and clean away the deposits before proceeding
• Additional cleaning must be carried out prior to
  working on the high pressure fuel system, refer
  to Fuel System - Clean (PIL 18-00).

9806/6900-3
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19
15 - Engine 00 - General 00 - General
Check (Pressure)
Engine Compression Test This test is used to
diagnose suspected poor compression in one or
more of the engine cylinders. Use ServiceMaster
to control the test. Several factors can
influence the compression pressure, the
following conditions are assumed
rotating in the engine compartment.Before
starting this job make sure that you have no
loose clothing (cuffs, ties etc) which could get
caught in rotating parts.When the engine is
turning, keep clear of rotating parts.

1. To bleed the injectors you must turn the engine.
2. Get access to the engine.
3. Remove all six fuel injectors. Refer to (PIL
   18-18).
4. Make sure that the injectors are labelled for
   correct installation at a later stage.
5. Install the dummy injector in one of the vacant
   cylinder injector bores. Refer to Figure 13.
6. Install the dummy injector in one of the vacant
   cylinder injector bores.
7. Note The dummy injector is drilled and tapped
   1/8-28 BSP x 8 mm deep to accept a standard
   pressure gauge fitting.
8. Operate the starter motor to crank the engine.
9. Do not crank for longer than 20 seconds.
10. Record the gauge reading.
11. Do steps 3 to 6 again for the remaining five
    cylinders.

• The valve clearances have been set correctly.
  Refer to (PIL 15-30).
• The correct engine oil has been used. Refer to
  (PIL 75-03).
• The engine oil level is correct. Refer to (PIL
  15-21).
• The correct type of diesel fuel has been used
  and the system correctly primed, refer to (PIL
  75-18).
• The battery and starting circuit is fully charged
  and in good condition, e.g. good earth paths,
  cable connections tight etc.

When comparing the figures recorded in the
following procedures, there should be a minimum
variation of 3.5 bar (50.7psi) between each
cylinder. If the variation is greater than this
figure, then remove the cylinder head, refer to
(PIL 15-21) and closely inspect the cylinder
bores, pistons and piston rings for signs of
wear or damage. Repair as necessary.
WARNING! To bleed the injectors you must turn the
engine. When the engine is turning, there are
parts
9806/6900-3
15 - 26
20
15 - Engine 00 - General 00 - General
Figure 13.
0 50
0
0
50
50
A
A Dummy Injector
9806/6900-3
15 - 26
21
15 - Engine 00 - General 00 - General
Remove and Install
Special Tools
recommended lifting equipment is shown. Use a
spreader bar when lifting the engine. Never
attempt to manually lift heavy components on
your own. Always use lifting equipment, or
obtain the help of an assistant. Inspect the
lifting brackets for signs of damage. The
brackets must be correctly torqued to the
crankcase. Make sure the lifting equipment does
not damage any of the engine dressing and the
rocker cover.
Description Part No. Qty.
Lifting Bracket Front 320/09425 1
Lifting Bracket Front 320/09426 1
Engine Lifting Spreader Bar 892/01382 1
Lifting Equipment You can be injured if you use
incorrect or faulty lifting equipment. You must
identify the weight of the item to be lifted
then choose lifting equipment that is strong
enough and suitable for the job. Make sure that
lifting equipment is in good condition and
complies with all local regulations.
Component Identification The following component
identification is for a typical engine
installation. There will be some component
differences depending on the machine variant.
Before attempting to remove the engine ensure
that all the necessary components have either
been removed, or safely disconnected from the
engine.
The lifting equipment used must be an approved
type and capable of lifting the engine safely. The
9806/6900-3
15 - 26
22
15 - Engine 00 - General 00 - General
Figure 14.
H
G
B
A
A
C
F
D
E
J
M
K
L
A Lifting brackets C Electrical connections -
alternator E Electrical earth connection -
starter motor G Coolant port - heater hose
B Exhaust port - turbocharger D Electrical
connector - oil level switch F Electrical
connections - starter motor H Electrical
connector - coolant temperature sensor K Fuel
line connections - fuel injection pump M Ports -
remote oil cooler hoses
J Throttle cable connection - fuel injection
pump L Electrical connector - oil pressure sensor
9806/6900-3
15 - 26
23
15 - Engine 00 - General 00 - General
Remove

• converter clear of the engine, make sure that the
  torque converter stays mounted on the gearbox
  shaft.
• Attach slings to the engine lifting eyes. Install
  the engine lifting spreader bar.
• Special Tool Lifting Bracket Front (Qty. 1)
  Special Tool Lifting Bracket Front (Qty. 1)
  Special Tool Engine Lifting Spreader Bar (Qty.
  1)
• Take the weight of the engine on the hoist and
  remove the engine mounting bolts.
• Withdraw the engine in a level attitude until the
  hydraulic pump is clear of the chassis. Raise
  the engine to lift it clear of the machine.
• Lower the engine into a suitable stand that is
  capable of supporting the weight of the engine.
• Figure 15.
• C

1. Make sure that the engine is safe to work on. If
   the engine has been running, let it cool before
   you start the service work.
2. Position the machine on firm level ground. Make
   the machine safe. Refer to (PIL 01-03).
3. Discharge the hydraulic pressure. Refer to (PIL
   30-00).
4. Get access to the engine.
5. Disconnect the battery. Refer to (PIL 33-03).
6. Drain the engine oil. Refer to (PIL 15-21)
7. Drain the engine coolant. If necessary remove
   the cooling pack refer to (PIL 21-03).
8. If applicable, drain the hydraulic tank.
   Disconnect and plug the hydraulic suction and
   delivery lines at the engine driven hydraulic
   pumps. Label the hoses to ensure correct
   reassembly.
9. Disconnect the throttle cable at the fuel
   injection pump.

1. If applicable, disconnect and plug the remote oil
   filter hoses at the oil cooler housing. Label
   the hoses to ensure correct reassembly
2. Disconnect the exhaust system.
3. Label the cab heater hose at the cylinder head.
   Release the hose clip and remove the hose.

B

1. Disconnect the wiring connections starter motor.
   Refer to (PIL 15-75)
2. Disconnect the wiring connections alternator.
   Refer to (PIL 15-72)

from the from the
15. Disconnect the wiring connections from the
engine sensors and actuators. Refer to (PIL
15-84).

1. Disconnect the electrical connector at the oil
   level sensor (if installed).
2. Disconnect the fuel supply line at the fuel lift
   pump and the spill line at the fuel injection
   pump. Cap all hoses and ports to prevent ingress
   of dirt.
3. Ensure that all relevant harnesses and hoses are
   unclipped from the engine and tied out of the
   way.
4. If applicable disconnect and plug the hoses at
   the hydraulic pump.
5. If applicable disconnect the electrical
   connectors at the hydraulic pump.
6. If applicable remove the gearbox to engine
   retaining bolts, move the gearbox and torque

A

1. Lifting bracket mounting bolts
2. Spreader bar
3. Lifting equipment

9806/6900-3
15 - 26
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15 - Engine 00 - General 00 - General

• Install
• Replacement is a reversal of the removal
  procedure.
• On engines with a torque converter it is vitally
  important that the torque converter is installed
  at the gearbox and engine flywheel correctly.
  Failure to locate the converter correctly will
  result in damage to the gearbox oil pump on
  engine start up.
• Fill the cooling system with the correct mix of
  coolant fluid.
• Fill and check the hydraulic fluid level.
• Fill and check the engine oil level.
• On completion, check the hydraulic and cooling
  system for leakage and levels.
• Table 26. Torque Values

Item Nm
A 47
15 - 33
9806/6900-3
15 - 33
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the link into your browser. The full manual is
available for immediate download. https//www.eb
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