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320 HYDRAULIC EXCAVATOR3066 ENGINE

MEETING GUIDE 622 SLIDES AND SCRIPTAUDIENCE

Level II - Service personnel who understand the principles of machine systems operation, diagnosticequipment, and procedures for testing and adjusting.

CONTENT

This presentation covers the 3066 engine as configured for the 320 Hydraulic Excavator. This

presentation provides an orientation to all of the 3066 engine systems and describes system operation

and in-chassis testing and adjusting of the fuel system.

OBJECTIVES

After learning the information in this presentation, the serviceman will be able to:

1. locate service points on the 3066 Engine;

2. explain the operation of the fuel pump and governor;

3. explain the interface between the engine and the electronic control unit; and

4. perform in-chassis adjustments to the fuel system.

SUPPLEMENTARY TRAINING MATERIAL

STMG 619 "320/330 Hydraulic Excavators -- Pumps and Pump Controls" SESV1619

STMG 620 "320/330 Hydraulic Excavators -- Hydraulic Systems Operation" SESV1620

STMG 621 "320/330 Hydraulic Excavators -- Electronic Control Unit" SESV1621

Estimated Time: 2 Hours

Visuals: 52 (2 X 2) Slides

Serviceman Handouts: 6 line drawings

Form: SESV1622

Date: 7/92

1992 Caterpillar Inc.

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TABLE OF CONTENTS

INTRODUCTION.....................................................................................................................................5

AIR INDUCTION AND EXHAUST SYSTEM.......................................................................................7

LUBRICATION SYSTEM......................................................................................................................12

COOLING SYSTEM ..............................................................................................................................21

FUEL SYSTEM ......................................................................................................................................25

Component Location .........................................................................................................................25

Fuel Pump Operation.........................................................................................................................28

Governor Control System Operation.................................................................................................35

IN-CHASSIS FUEL SYSTEM TESTS AND ADJUSTMENTS ...........................................................46

High and Low Idle.............................................................................................................................46

Idling Sub-spring and Full Load........................................................................................................47

Fuel Nozzle Test ................................................................................................................................50

Fuel Timing .......................................................................................................................................52

Fuel Pump and Governor Removal ...................................................................................................57

CONCLUSION .......................................................................................................................................60

SLIDE LIST ............................................................................................................................................61

SERVICEMAN'S HANDOUTS..............................................................................................................63

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INSTRUCTOR NOTES

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320 Hydraulic

Excavator with 3066

engine

Water cooled, 4-stroke

turbocharged, 6

cylinder

1

INTRODUCTION

The Caterpillar 3066 engine provides power for the 320 Hydraulic

Excavator. This presentation will discuss the air inlet and exhaust,

lubrication, cooling, and fuel systems of the 3066 engine. The 3066

engine is a water cooled, four-stroke, turbocharged, in-line six cylinder

diesel engine. The 3066 engine in the 320 Hydraulic Excavator produces

97 kW (130 horsepower) at 1800 rpm.

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Hydraulic pumps

1. Power shift hose

2. Proportional

reducing valve

solenoid harness

2

The engine drives the variable displacement, axial piston, tandem

hydraulic pumps.

NOTE: This slide shows the power shift pressure hose (1) and the

proportional reducing valve solenoid wire harness (2).

2

1

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Canister-type dry

filtering air filter

3

AIR INDUCTION AND EXHAUST SYSTEM

Air flows through this canister-type dry filtering air filter before reaching

the turbocharger. The air filter is behind the access door on the left side

of the engine.

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Replace air filter when

indicator (arrow)

shows red

4

When dirt plugs the air filter element, engine performance can decrease.

The air filter indicator (arrow) shows when the air filter requires

servicing. When replacement of the air filter is necessary, the air filter

indicator will show red in the indicator window.

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Air intake system

components:

1. Turbocharger

impeller

2. Exhaust manifold

3. Turbocharger turbine

"Boost" definition

5

After flowing through the air filter, air enters the inlet side (impeller) of

the turbocharger (1). The turbocharger forces air through the inlet

manifold and into each cylinder chamber during the engine intake stroke.

After combustion, the exhaust valve opens and the piston forces the

exhaust gasses out of the cylinder, through the exhaust manifold (2) and

into the exhaust side (turbine) of the turbocharger (3). The momentum of

the gas from the exhaust stroke spins the turbine and causes the impeller

to force more air into the inlet manifold.

The air pressure in the inlet manifold is referred to as "boost." Boost

pressure can give an indication of engine performance. If boost pressure

is low, the engine will not produce rated horsepower under full load

conditions. Likewise, if the engine is not producing rated horsepower

under full load conditions, boost pressure will be low (even if the

problem is not in the air intake and exhaust system).

1

2

3

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Inlet manifold heater

(arrow)

6

During cold weather, diesel engines are sometimes difficult to start

because the compression stroke cannot sufficiently heat the cold inlet air

enough to allow complete fuel combustion. To increase engine

startability during cold weather, the 3066 engine can be ordered with an

optional inlet manifold air heater (arrow). When in use, the inlet manifold

heater heats the inlet manifold and the inlet air before the air enters the

cylinders.

Do not use ether with this attachment. Using ether with the inlet

manifold heater could cause engine damage as well as personal injury

or death.

WARNING

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Turn key to left

(arrow) to activate

inlet manifold heater

7

Turning the key switch to the left position (arrow) activates the inlet

manifold heater. After heating the inlet manifold air for approximately 30

seconds, an indicator light in the control panel turns ON. After the

indicator light turns ON, the operator should start the engine. The inlet

manifold heater is on only when the key is in the left position.

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Gear-type oil pump

(arrow)

8

LUBRICATION SYSTEM

A timing gear drives the gear-type oil pump (arrow). The oil pump

circulates oil through the engine to provide cooling, cleaning, protection,

sealing, and lubrication. Correct maintenance of the lubrication system is

essential to engine life.

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Spin-on oil filter

(arrow)

Bypass valve

9

From the oil pump, oil flows to the spin-on oil filter (arrow). As with the

air filter, oil filters should be correctly maintained. A plugged oil filter

causes increased oil pressure between the pump and the filter. When oil

pressure between the pump and filter increases above a specified pressure,

the bypass valve inside the oil filter (the bypass valve is not in the filter

manifold) allows oil to flow around the filter to the remaining

components in the lubrication system. When oil bypasses the filter, the

oil pump delivers unfiltered oil to the engine components.

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Oil cooler

10

Oil from the oil filter flows through the oil cooler. Engine coolant

provides cooling for the oil.

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Shim adjustable oil

pressure relief valve

(arrow)

11

When pressure in the lubrication system reaches 343 kPa (50 psi), the

relief valve (arrow) will open and vent the excess flow back to the oil pan.

This valve provides the main relief for the lubrication system. The

lubrication system relief valve is shim adjustable.

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Lubrication system oil

pressure tap (arrow)

13

The 3066 engine has a pressure tap (arrow) that allows the lubrication

system oil pressure to be measured. This pressure tap is on the side of the

engine toward the rear of the machine. The lubrication oil pressure

should be between 196 and 392 kPa (28 and 57 psi) with the engine

running at 1500 rpm.

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Lubrication oil

pressure sensor

(arrow)

14

A pressure sensor (arrow) monitors the lubrication oil pressure. When the

lubrication oil pressure is not within specifications, the pressure sensor

signals the machine monitoring system to warn the operator.

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Engine oil dipstick

(arrow)

15

The dipstick (arrow) indicates the engine oil level.

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Engine oil fill port

(arrow)

16

If the dipstick indicates that the oil level is low, add oil through the oil fill

port (arrow) on top of the engine.

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Conventional radiator

Pressurized cap

(arrow)

17

COOLING SYSTEM

As in the lubrication system, correct maintenance of the cooling system is

essential to machine life. Cooling system problems cause a large number

of engine failures. The radiator serves as the reservoir and heat exchanger

for the engine coolant. The 320 Hydraulic Excavator has a conventionalradiator with an overflow bottle. The pressurized cap (arrow) should

never be removed when the engine is hot.

At operating temperatures, the engine coolant is hot and under

pressure. The radiator and all lines to heaters or the engine contain

hot water or steam. Any contact can cause severe burns.

Steam can cause personal injury. Check the coolant level only afterthe engine has been stopped and the filler cap is cool enough to

remove with your bare hand. Remove the cooling system filler cap

slowly to relieve pressure.

Cooling system conditioner contains alkalis that can cause personal

injury. Avoid contact with the skin and eyes and do not drink. Allow

cooling system components to cool before draining. When draining

the cooling system, catch all of the coolant in a suitable container and

dispose of coolant in an environmentally sound manner.

WARNING

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Radiator overflow

bottle

18

The radiator overflow bottle collects engine coolant if the engine

temperature exceeds the boiling point of the coolant. Lines on the bottle

indicate when the cooling system is full and when the system needs

additional coolant.

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Centrifugal-type water

pump (arrow)

19

The belt and pulley system drives the centrifugal-type water pump

(arrow) and fan. The water pump circulates the coolant through the

engine.

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Fuel system

components:

1. Transfer pump

2. Priming pump

Priming procedure

21

FUEL SYSTEM

Component Location

A piston-type fuel transfer pump (1) delivers fuel from the tank to the

main fuel pump. The fuel camshaft drives the fuel transfer pump. If the

machine runs out of fuel or the filter is changed, the fuel priming pump

(2) can be used to prime the fuel system.

To prime the fuel system, unlock the priming pump by turning the pump

knob in the counterclockwise direction. After unlocking the knob,

operate the pump. Loosen the air vent plugs on the fuel filter manifold to

prime the filter and on the governor to prime the main pump and fuel lines

(discussed later).

1

2

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Fuel filter is

downstream from

transfer pump

Always use the

priming pump to

prime system

Open air vent plug

(arrow) when priming

Install gauge in air

vent plug (arrow) tocheck fuel pressure

22

The fuel flows through a filter before entering the main fuel pump. The

spin-on fuel filter should be maintained at regular intervals. If dirt and

debris plug the fuel filter, the filter bypass valve opens and allows the

transfer pump to supply unfiltered fuel to the main fuel pump.

NOTICE

When installing a new fuel filter, never pour fuel into the filter to

prime the fuel system. To ensure that no unfiltered fuel enters the

fuel system during a filter change, always use the fuel priming pump

to prime the fuel system. When priming, open the air vent plug

(arrow) to allow air to escape from the system. The system is primed

when fuel flows from the air vent plug without air bubbles. Be sure

to catch the fuel from the air vent in a suitable container and dispose

of it in an environmentally sound manner. Replacing the air ventplug with a pressure gauge measures fuel pressure between the

transfer pump and the filter.

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Fuel pump and

governor components:

1. Main fuel pump

2. Scroll-type fuel

pump

3. Governor

4. Governor actuator

mechanism

5. Shutoff solenoid

6. Air vent plug

23

The main fuel pump (1) is an in-line cam-type pump consisting of six

individual scroll-type fuel pumps (2). A gear which is timed to the engine

crankshaft drives the main fuel cam. The governor (3) controls the

amount of fuel that the individual fuel pumps deliver to the cylinders

through a fuel control rack. The governor is electro-mechanically

actuated through a cable and pulley system (4). When energized, the

shutoff solenoid (5) moves the fuel rack to the FUEL OFF position

regardless of throttle position.

NOTE: When priming the fuel pump and fuel lines, loosen the air

vent plug (6). The system is primed when fuel flows from the air vent

plug without air bubbles. Be sure to catch the fuel from the air vent

in a suitable container and dispose of it in an environmentally sound

manner.

1

2

3

4

5

6

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Fuel system diagram

Excess fuel returns to

tank through fuel

return line

FUEL FILTER FUEL INJECTION NOZZLES

FUEL

OVERFLOW

LINE

CHECK

VALVE

FUEL INJECTION PUMP

FUEL TRANSFER

AND PRIMING PUMPS

FROM

FUEL TANK

TO

FUEL TANK

FUEL RETURN LINE

3066 FUEL SYSTEM

Fuel Pump Operation

This slide shows the flow through the fuel system. The fuel transfer pump

delivers fuel from the tank to the fuel filter. The fuel filter cleans the fuel

before it enters the main pump. The main pump contains six individual

fuel pumps. Each individual fuel pump delivers high pressure fuel to a

fuel injection nozzle through a fuel line. The fuel nozzles spray atomized

fuel into the cylinders.

The fuel transfer pump supplies more fuel to the main fuel pump and the

individual cylinder fuel pumps supply more fuel to the injector nozzles

than the engine needs. The excess fuel delivered to the main pump and

injection nozzles serves a lubrication, cooling and cleaning function

before returning to the tank through the fuel return line.

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Camshaft drives the

transfer pump

Piston chamber

spring returns piston

to bottom

Discharge check valve

closes and suction

valve opens

FUEL TRANSFERAND PRIMING PUMPS

SUCTION

CHECK VALVE

SUCTION

PISTON

CAMSHAFT

TAPPET

DISCHARGE

CHECK VALVE

PRIMING PUMP

The camshaft drives the transfer pump. A tappet and pushrod assembly

converts the rotational motion of the camshaft to reciprocating motion.

The pushrod moves the piston. The reciprocating motion of the piston

creates alternating suction and discharge cycles. As the tappet moves

down the cam lobe, the piston chamber spring returns the piston to the

bottom position. The returning motion of the piston forces the fuel in the

bottom of the piston chamber into the fuel injection pump supply line and

also creates decreased pressure in the piston spring chamber. The

pressure in the discharge line is now higher than the pressure in the pistonspring chamber, and the discharge check valve closes. The decreased

pressure in the piston spring chamber also allows the suction check valve

to open allowing fuel from the tank to fill the chamber.

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Tappet motion forces

piston to compress

spring

Suction valve closes

and discharge valve

opens

Piston spring

returning action

pumps the fuel


DISCHARGE

CHECK VALVE

SUCTION

PISTON

CAMSHAFT

TAPPET

DISCHARGE

CHECK VALVE

PRIMING PUMP

As the cam lobe pushes the tappet up, the piston compresses the piston

chamber spring. As the piston raises, the motion creates an increased

pressure in the piston spring chamber. The increased pressure in the

piston spring chamber closes the suction check valve and opens the

discharge check valve. Fuel flowing by the discharge check valve fills the

chamber under the piston (some fuel also enters the fuel injection pump

supply line) until the tappet reaches the peak of the cam lobe. As the

tappet starts to descend the cam lobe, the piston spring returns the piston

to the bottom of the chamber and forces the fuel in the chamber out thedischarge port into the fuel injection pump supply line.

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Transfer pump

provides a regulating

function


REGULATING

CHECK VALVE

SUCTION

PISTON

CAMSHAFT

TAPPET

DISCHARGE

CHECK VALVE

PRIMING PUMP

If the fuel discharge pressure increases abnormally, the fuel pressure in the

chamber under the piston can counteract the piston chamber spring force.

When the fuel pressure in the chamber under the piston and the spring

force reach the equilibrium point, the piston will not continue to descend

the cam lobe with the tappet, the fuel pressure inside the spring chamber

closes the suction check valve, and the fuel discharge pressure keeps the

discharge check valve closed. In this condition, the fuel transfer pump

provides a regulating function.

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Effective stroke

definition

Injection ends after

scroll is open to

discharge port

PLUNGER

BARREL

PLUNGER

EFFECTIVE

STROKE

HELIX

SUCTION AND

DISCHARGE PORT

DELIVERY STARTS DELIVERY ENDS

FUEL INJECTION PLUNGEREFFECTIVE STROKE

As the governor moves the control rack, the movement changes the

effective stroke of the plunger which changes the amount of fuel injected.

The effective stroke is the distance the plunger moves up from the point

where the top of the plunger closes the suction and discharge port to the

point where the scroll opens the suction and discharge port. After the

scroll opens the suction and discharge port, pressure above the plunger

decreases. The decreased pressure above the plunger allows the delivery

valve spring to close the delivery valve and end fuel injection, even if the

plunger continues to move up.

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Main pump supplies

fuel to fuel injection

nozzles

Injection pressure is

shim adjustable

NOZZLE BODY

SHIM PRESSURE SPRING

PRESSURE PIN

TIP PACKINGPIN

NOZZLE TIP

RETAINING NUT

FUEL INJECTION NOZZLE

The main fuel injection pump supplies high pressure fuel to the fuel

injection nozzle through the injection lines. When the pressure in the

injection lines reaches 22065 to 23046 kPa (3200 to 3342 psi), the nozzle

will inject fuel into the combustion chamber. Injection pressure can be

changed by changing the thickness of the shim behind the pressure spring

in the fuel injection nozzle. A 0.1 mm (0.004 in.) change in shim

thickness causes a 1373 kPa (200 psi) change in the injection pressure.

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Engine starts to

overspeed

Flyweights move out

Sleeve and shifter

compress torque

control spring

Tension lever moves

right

Spring and flyweight

force equalizes

CONTROL RACK

GOVERNOR SPRING

SWIVEL LEVER

CAMSHAFT

FLYWEIGHTSSHIFTER

AND SLEEVE

CONTROL LEVER FLOATING LEVER

LOW IDLE STOP

IDLING

SUB-SPRING

TENSION LEVER

TORQUE

CONTROL SPRING

FULL LOAD

ADJUSTMENT SCREW

NO LOAD MAXIMUM SPEED

GOVERNOR OPERATION

SHUTOFF LEVER

Governor Control System Operation

This illustration shows governor operation when the engine speed starts to

exceed the speed that the throttle control lever specifies. As the engine

starts to overspeed, the centrifugal force of the flyweights causes the

flyweights to move out. As the flyweights move out, the shifter and

sleeve move to the right until contacting and compressing the torque

control spring. After the sleeve and shifter compresses the torque control

spring, the tension lever moves to the right. Moving the tension lever tothe right stretches the governor spring. Stretching the governor spring

increases the tension of the spring. The spring tension and the centrifugal

force of the flyweights will eventually reach an equilibrium point and the

tension lever will stop moving.

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Floating lever moves

to right

Control rack moves to

right until spring and

flyweight forceequalizes

Tension lever

contacts idling sub-

spring

Torque control spring

limits black smoke

Moving rack to left is

FUEL ON

At the same time that the flyweights, shifter, and sleeve are moving the

tension lever, they are also moving the floating lever to the right. The

mechanical linkage connecting the floating lever to the control rack

moves the control rack to the right. Moving the control rack to the right

decreases the amount of fuel that the fuel injection pump supplies to thefuel injection nozzles. The control rack will continue to move to the right

until the governor spring and the flyweights reach the equilibrium point.

If engine speed continues to increase, the tension lever continues to move

to the right until it contacts the idling sub-spring. After the tension lever

compresses the idling sub-spring, the control rack is in the NO LOAD

MAXIMUM SPEED condition.

The function of the torque control spring is to limit the amount of black

smoke the engine produces during acceleration. When the engine speed islow, the torque control spring force is larger than the centrifugal force of

the flyweights. The spring force moves the shifter and sleeve to the left.

Moving the shifter and sleeve to the left moves the guide and floating

levers to the left causing the control rack to move toward the FUEL ON

direction. As the engine speed increases, the centrifugal force of the

flyweights compresses the torque control spring. The shifter will then

contact and move the tension lever to decrease the fuel injection quantity.

In this governor, pushing the rack in decreases fuel and pulling the rack

out increases fuel.

NOTE: The control lever and shutoff lever in this illustration are not

the actual mechanisms on the 3066 engine in the 320 Hydraulic

Excavator. The actual throttle control mechanism on the 3066 engine

in the 320 Hydraulic Excavator is not a lever, but rather, a pulley and

cable system. The shutoff lever is a solenoid operated control.

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Controller location

32

All of the electrical inputs for engine speed control go through the

controller. The controller is on the left side of the machine, behind the

same access door as the air filter canister.

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Governor control

inputs:

1. AEC switch

2. Power mode switch

3. Engine speed dial

4. Hydraulic pressure

switches

5. One-touch low idle

switch

6. Backup switches

7. Feedback sensor

Controller signals

governor motor

MONITORENG.

SPEED

DIALTRAV.

PRESS.

SWITCH

BM. UP

PRESS.

SWITCH

IMP L. /SW.

PRESS.

SWITCH

LOW

IDLE

SWITCH

SPEED

CHANGE

SWITCH

SPD. DIAL

BACKUP SW.

ENGINE

PUMP

G/A

FUSE

BOX

START

SWITCH

SPEED

SENSOR

BATTERY

ECU (CONTROLLER)

G/A FDBK

SENSOR

ELECTRONIC CONTROL SYSTEM

ENGINE SPEEDINPUT COMPONENTS

This simplified schematic of the machine control system shows only the

input components that control the governor motor. The input components

are the automatic engine speed control (AEC) and the power mode

functions in the control panel; the engine speed dial; the implement/swing,

travel, and attachment pressure switches; the one-touch low idle switch on

the right implement control lever; the backup switch for the throttle

control; and the position feedback sensor in the governor actuator motor.

The controller compares the input signal from the engine speed dial to theinput signal it receives from the position feedback sensor. If the position

feedback sensor and the engine speed dial do not agree, the controller

signals the governor motor to move the governor control lever to the

correct position.

NOTE TO THE INSTRUCTOR: For a complete, detailed

description of how the electronic control system operates, see

STMG 621 "320/330 Hydraulic Excavators Electronic Control

Unit" (Form SESV1621).

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Governor actuator

motor location (arrow)

34

The governor actuator motor (inside metal box, arrow) is on the left side

of the machine behind the access door. The governor actuator motor

receives electrical signals from the controller.

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Position feedback

sensor (arrow)

35

The governor control cables wrap around a pulley that is connected to the

position feedback sensor (arrow) in the governor actuator motor.

Electrical signals to the governor actuator motor cause the feedback

sensor and pulley to rotate. The rotating pulley moves the cable which in

turn moves the governor throttle control lever.

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Engine speed backup

switches allow LOW

and HIGH IDLE

operation

1. Auto/manual switch

2. Speed toggle switch

Possible to operate at

an intermediate speed

37

The engine speed control circuit contains backup switches (located in the

operators station, under a cover, at the rear of the right arm rest) which

allow the operator to bypass the engine speed dial. To operate the engine

at LOW IDLE, position the manual/auto switch (1) in the "MAN"

position and hold the two-position, spring-centered speed toggle switch

(2) toward the "Tortoise" until the engine speed stops decreasing. To

operate the engine at HIGH IDLE, hold the speed switch (2) toward the

"Rabbit" until the engine speed stops increasing. To operate the engine at

an intermediate speed, release the speed toggle switch before the engine

reaches either high or low idle.

12

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Two levels of AEC

1. AEC switch

2. Power mode

selector switch

First level AEC

operates with AEC

switch (1) OFF

Second level AEC

operates with AEC

switch ON and engine

speed dial above 5

Power mode switch

(2) determines engine

rpm

Each power mode

level corresponds to

an engine speed dial

position

38

The AEC function improves fuel consumption and noise level by

reducing engine speed during no load conditions. The AEC function has

two levels of operation. The first level operates when the AEC switch (1)

is OFF. The first level occurs approximately three seconds after the

engine load requirements stop. The swing, travel, and attachment

pressure switches send signals to the controller which tell the controller

when engine load requirements end. When the load requirements end, the

controller signals the governor motor to reduce the engine speed by

approximately 100 rpm.

The second AEC level occurs only when the AEC switch is ON and the

engine speed dial is at 5 or above. The second level automatically

reduces engine speed to approximately 1300 rpm if, after 3 seconds, the

engine does not encounter a load. When one of the pressure switches

turns ON (loaded condition), the engine speed returns to the speed that the

speed dial indicates.

The power mode selector switch (2) is also in the control panel. The

power mode level determines the maximum engine speed independently

of engine speed dial position. Power Mode III allows the full range of

throttle operation (engine speed dial positions 1-10). Power Mode II

limits the maximum engine speed to position 9 and Power Mode I limits

maximum engine speed to position 7, regardless of the engine speed dial

position. The machine defaults to Power Mode II at start-up.

12

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One-touch low idle

switch (arrow)

Loading the machine

automatically returns

engine to normal

operating rpm

40

The right implement control lever contains the one-touch low idle switch

(arrow). When the operator activates the one-touch low idle switch, the

controller signals the governor motor to reduce the engine speed to

approximately 940 rpm. When the operator pushes the switch a second

time, engine speed increases to either the engine speed dial level, the

power mode level, or the AEC level (whichever is lowest). If the operator

activates a function, the one-touch low idle control switch will

automatically turn OFF and engine speed returns to the normal operating

rpm level.

NOTICE

The engine speed dial should be in position 1 before the engine is shut

down. If the operator turns the machine OFF with the one-touch lowidle switch active (engine speed at approximately 940 rpm) and does

not return the engine speed dial to position 1 before the machine is

restarted, upon restarting, the engine speed will accelerate to the

engine speed dial setting or the Power Mode II level -- whichever is

lowest. The controller DOES NOT retain memory that the one-touch

low idle switch was active at engine shutdown.

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Governor components:

1. Idling sub-spring

2. Torque control spring

3. Full load adjustment

screw

Idling sub-spring

maintains constant

engine rpm at LOW

IDLE

Adjusting idling sub-

spring can cause

engine to overspeed

Full load adjustment

screw limits rack travel

42

Idling Sub-spring and Full Load

This view of the governor shows the access cover to the idling sub-spring

(1), the torque control spring (2, behind cover), and the full load

adjustment screw (3).

The function of the idling sub-spring is to maintain a constant engine rpm

at LOW IDLE. If the engine rpm fluctuates abnormally at LOW IDLE,

the idling sub-spring may not be in contact with the governor tension

lever allowing the control rack position to float. Tightening the idling

sub-spring adjusting screw until the spring just contacts the tension lever

prevents the control rack position from floating. With the idling sub-

spring applying some force on the tension lever, the low idle speed will

increase slightly but will stop fluctuating.

When working the machine, the engine may overspeed after removing a

load if the idling sub-spring force against the tension lever is too high.When adjusting the idling sub-spring tension, tighten the adjusting screw

just enough to eliminate the unstable LOW IDLE condition.

The function of the full load adjustment screw is to limit rack travel

during FULL LOAD conditions. The full load adjustment screw provides

a positive stop for the floating lever in the governor. Turning the full load

adjustment screw clockwise increases the fuel injection quantity while

turning the bolt counterclockwise decreases the fuel injection quantity.

1

2

3

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Cannot measure

engine output under

full load conditions on

standard machine

Standard 3066 engine

does not have a boost

pressure tap

Since the engine produces maximum horsepower when the floating lever

contacts the full load adjustment screw (with the engine at full load rpm),

a misadjusted full load adjustment screw can cause the engine horsepower

to be out of specification. However, engine output cannot be measured

under FULL LOAD conditions with a standard 3066 engine in the 320Hydraulic Excavator because the engine does not have a boost pressure

tap and the controller destrokes the hydraulic pumps before the engine

reaches full load [see STMG 619 "320/330 Hydraulic Excavators

Pumps and Pump Controls" (Form SESV1619)]. If the engine has a

power problem and after checking all other possibilities (such as fuel

grade, governor control mechanism functioning correctly, altitude

deration, plugged air and fuel filters, air in the fuel lines, fuel nozzles

functioning correctly, and correct injection timing), the engine should be

tested on a dynamometer.

NOTE: With a minor engine modification, it is possible to check

engine horsepower with the engine in chassis. This procedure

requires drilling a boost pressure tap in the air intake system,

disconnecting the controller signal to the hydraulic pumps (either

disconnect the proportional reducing valve harness or disconnect and

plug the power shift pressure hose), and loading the engine with the

swing and bucket hydraulic circuits while measuring engine rpm and

boost pressure.

To perform this procedure, operate the swing motor against the swing

lock pin. Then, slowly load the bucket while measuring the engine

speed. When the engine speed decreases to approximately 1700 rpm

(100 rpm below full load speed), gradually decrease the bucket load.

Decreasing the bucket load will cause an increase in engine rpm and

boost pressure. Boost pressure will increase to maximum, then start

to decrease. Record the boost pressure and engine speed when the

boost pressure is highest. Since the engine produces maximum

horsepower at maximum boost pressure, comparing the recorded

engine speed and boost pressure with engine specifications will

indicate if the engine is producing rated horsepower. Boost pressure

at 1800 rpm should be 500 50 mm Hg (9.7 1 psi). If the engine is

not producing sufficient boost pressure at FULL LOAD speed, it is

also not producing rated horsepower. This test should be used for

determining engine performance for troubleshooting purposes only.

This test is not accurate enough to make full load screw adjustments.

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NOTICE

The timing gear housing interferes with the in-chassis rack travel

measurement. Currently, there is no way of knowing if adjusting thefull load adjustment screw moves the rack travel distance out of

specification. Engine dynamometer testing and the fuel test bench

provide the safest and most accurate way to adjust engine

horsepower.

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Fuel injection nozzle

test procedure

Fuel injection nozzle

removal procedure:

1. Loosen supply line

2. Loosen return line

3. Loosen bolt and

remove clamp

43

Fuel Nozzle Test

If engine performance is low, a malfunctioning fuel injection nozzle may

be the cause. To test a fuel injection nozzle, operate the engine at HIGH

IDLE (using the engine speed dial bypass switches) and measure the

engine speed. After recording the HIGH IDLE rpm, loosen the fuel

supply line (1) to the suspected injector and direct the fuel flow from the

line into a suitable container. With the fuel supply line loose, operate the

engine at HIGH IDLE and measure the engine rpm. If the engine speed

decreases from the previous HIGH IDLE measurement, the performance

problem is probably not related to that injector. If the high idle speed

remains the same as before disconnecting the fuel supply line, remove the

injector and test it on a nozzle test stand. If the injector is defective,

either repair or replace it. Then, recheck the engine performance.

To remove a fuel injection nozzle, loosen the fuel return line (2) from

each injector and remove the line. After removing the return line, loosen

the bolt (3) and remove the clamp. The injector should pull straight out of

the head. If the injector does not slide out of the head easily, use a wrench

to turn the injector while pulling the injector out.

1

2

3

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Never allow the fuel from the fuel line to spill on the hot engine or on

the ground. Engine heat may be sufficient to cause fuel combustionwhich could result in personal injury and property damage. Diesel

fuel is a hazardous material and must not be allowed to contaminate

the environment.

WARNING

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Engine timing gears

1. TDC reference mark

2. TDC reference mark

3. Fuel timing gear

44

Fuel Timing

Incorrect fuel injection timing can cause low engine performance. The

engine timing gears have reference marks (1 and 2) that mesh when the

No. 1 cylinder is at top dead center. The fuel timing gear (3) drives the

fuel camshaft. Rotating the main fuel pump relative to the fuel timing

gear changes fuel injection timing

1

2

3

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1. Scale

2. Retaining bolts

Scale indicates fuel

pump position

Each mark represents

a 6 timing change

45

This scale (1) on the injection pump indicates the position of the main

fuel pump relative to the timing gear. Each mark on the scale represents a

6 timing change. Loosening the retaining bolts (2) and rotating the top

of the pump toward the engine advances the injection timing, while

rotating the top of the pump away from the engine retards the injection

timing.

1

2

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Fuel injection timing

test procedure

1. Fuel line

2. Clamp

46

To check the fuel injection timing, disconnect the fuel line (1) from the

No. 1 fuel pump. Loosen the clamp (2) and remove the delivery valve

holder. Remove the valve and spring from the delivery valve holder;

then, replace only the holder (see slide 28). Attach a spare injection line

to the No. 1 fuel pump and place the end of the pipe in a container

suitable for holding diesel fuel.

1

2

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Rotate crankshaft by

turning nut (arrow)

47

After preparing the No. 1 fuel pump, use a socket wrench to turn the nut

(arrow) and rotate the crankshaft until the No. 1 piston is approximately

60 before top dead center on the compression stroke.

NOTE: Checking valve clearances with the number one cylinder at

top dead center ensures that the cylinder is on the compression stroke

and not the exhaust stroke.

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Each mark on the

scale represents 5 of

crankshaft rotation

Pointer (arrow)

Injection timing is 16

BTDC

48

The pulley contains a scale that ranges from 0 to 40 and a pointer

(arrow). Each mark on the scale represents a 5 crankshaft rotation.

While pumping the fuel priming pump, rotate the engine crankshaft until

fuel stops flowing and read the number the pointer indicates on the scale.

The indicated number is the fuel timing advance. The fuel injection

timing specification for the 3066 engine in the 320 Hydraulic Excavator is

16 before top dead center. If the fuel injection timing is not 16 before

top dead center, rotate the fuel pump (as previously described) to change

the injection timing.

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Bench tests are the

most accurate test for

fuel pump and

governor

Remove bolts (1) to

remove pump without

timing gear

Remove bolts (2) and

(3) to remove pump

with timing gear

49

Fuel Pump and Governor Removal

The most accurate way to correctly test and adjust the pump and governor

is on a test bench. After disconnecting the main fuel supply line, fuel

injector supply lines, the fuel overflow line, the lubrication line, and all of

the governor control linkages, the pump and governor can be removed.

The pump and governor can be removed with or without the fuel timing

gear. To remove the pump and governor without the timing gear, loosen

the four bolts (1) from the timing gear housing. To remove the pump and

governor with the fuel timing gear, remove the five bolts (2) from the

timing gear housing cover and loosen the three retaining bolts (3).

1

2

3

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Taper and slot match

timing gear

50

The taper and slot at the end of the fuel camshaft allows the pump and

governor to attach to the fuel timing gear in only one position.

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Taper and slot match

camshaft

51

The taper and key slot in the timing gear matches the taper and key slot of

the fuel camshaft.

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52

CONCLUSION

This presentation discussed the 3066 engine as configured for use in the

320 Hydraulic Excavator. The information in this presentation should

help dealer service personnel understand the engine and how it relates to

the machine.

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1. Model view

2. Hydraulic pumps

3. Air filter

4. Air filter indicator

5. Turbocharger

6. Inlet manifold heater

7. Key switch

8. Engine oil pump

9. Engine oil filter

10. Engine oil cooler

11. Lubrication system main relief valve

12. Lubrication system backup relief valve

13. Lubrication system oil pressure tap

14. Lubrication system oil pressure sensor

15. Engine oil dipstick

16. Engine oil fill port

17. Radiator

18. Radiator overflow bottle

19. Water pump

20. Temperature regulator

21. Fuel transfer and priming pump

22. Fuel filter

23. Fuel pump and governor24. Fuel system diagram

25. Fuel transfer and priming pumps

illustration - SUCTION


illustration - DISCHARGE


illustration - REGULATING

28. Fuel injection pump illustration

29. Effective stroke illustration

30. Fuel injection nozzle illustration31. Governor operation illustration -

NO LOAD MAXIMUM SPEED

32. Controller

33. Engine speed input components schematic

34. Governor actuator motor

35. Position feedback sensor and full load

adjustment screw

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36. Engine speed control dial

37. Engine speed control backup switches

38. Electronic control unit

39. AEC operation graph

40. One-touch low idle switch

41. High and low idle adjustment screws

42. Idling sub-spring, torque control spring,

43. Fuel injection nozzle

44. Engine timing gears

45. Fuel timing reference scale

46. No. 1 injection pump

47. Crankshaft rotation nut

48. Timing reference scale

49. Fuel pump and governor removal screws

50. Taper and slot in fuel camshaft

51. Taper and slot in fuel timing gear

52. Model view

SLIDE LIST

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FUELTRANSFER

A

NDPRIMINGPUMPS

SUCTION

CHECKVALVE

SUCTION

PISTON

CAMSHAFT

TAP

PET

DISCHARGE

CHECKVALVE

PRIMINGPUMP

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FUEL

INJECTIONPUM

PTONOZZLE

DELIVERYV

ALVEHOLDER

DELIVER

YVALVESPRING

DELIV

ERYVALVE

PUMPHOUSING

FUELCHAMBER

CONTROLRACK

CONTROLSLEEVE

PLU

NGERSPRING

TAP

PET

CAMSHAFT

PLUNGER

CONTROLPINION

SUCTIONAND

DISCHARGEPORT

PLU

NGERBARREL

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CONTROLRACK

GOVERNORSPRIN

G

SWIVELLEVER

CAMSHAFT

FLYWEIGHTS

SHIFT

ER

ANDSLEEVE

CONTROLLEVER

FLOATING

LEVER

LOWI

DLESTOP

IDLI

NG

SUB-SPRING

TENSIONLEVER

TORQU

E

CONTROLS

PRING

FULLLOAD

ADJUSTMENT

SCREW

NOLOADMAXIMUMSPEE

D

GOVERNO

ROPERATIO

N

SHUTOFFLEV

ER

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MONIT

OR

ENG.

SPEED

DIAL

TRAV.

PRESS.

SWITCH

BM.UP

PRESS.

SWITCH

IMPL./SW

.

PRESS.

SWITCH

LO

W

ID

LE

SWITCH

SPEED

CHANGE

SWITCH

SPD.DIAL

BACKUPSW

.

ENGINE

PUMP

G/A

FUSE

BOX

ST

ART

SW

ITCH

SPEED

SENSOR

BATTER

Y

ECU

(CONTROLLER)

G/A

FDBK

SENSOR

ELECTRONICCONTROL

SYSTEM

ENGINESP

EEDINPUTCOM

PONENTS

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900

1100

1300

1500

1700

1900

5

10

15

HIGH

IDLE

AUTOMATICENGINECO

NTROL

ENGINERPM

TIME(SEC)A

ECSWITCH

OFF

AECSWITCH

ON

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