Isuzu L Series Manuel utilisateur

Table of Contents

UL-Series Diesel

Foreword 1

I. Introduction

Application Notes 2

Maintenance Schedule 3

General Family Information 4

II. Engine Component Description

Injection Pumps, Timing 5-8

Valve Train 9

Camshaft 10

Crank, Block, Pistons, Rods 11-14

Head Gasket 15

Cylinder Head 16

Lubrication 17-18

Cooling 19

III. Engine Servicing Procedures

Spill Port Timing 20

Valve Adjustment 21

Injector Service 22-24

Injector Pop-Off Test 25

Injector Leak Test 26

Glow plug Inspection 26

Hot plug Replacement 27

IV. Engine Repair Specifications – 3L 28-31

V. Engine Repair Specifications – 4L 32-35

VI. Component Failure Analysis 36-40

VII. Appendix – Misc. Service Information

Nozzle Troubleshooting Guide 41

Nozzle Performance & Diagnosis 42

Nozzle Holder Tightening Specifications 43-44

Turbo Diagnosis 45

Exhaust Temperature 46

Crankcase Pressure 46

Inlet Manifold Pressure 46

Used Oil Analysis 47

VIII. Isuzu Technology – L-Series Direct Injection 48-49

Foreword

UL-Series Diesel 1

This book is designed to cover several aspects of the L-series engines. L-series engines

currently in production are the 3LA, 3LB, 3LD, 4LB, 4LC, and the 4LE. This training

manual is divided into six sections to make referencing information easier.

The introduction covers engine application notes and maintenance schedule. Section two

is the engine component section that provides in-depth descriptions of each component.

This will include component operation and important points that are critical to the

disassembly, inspection and reassembly of the engine. Section three is the engine service

section, which illustrates important information regarding fuel injection operation and

routine fuel injection service items. Section four provides a comprehensive listing of all

the critical engine specifications for the 3L engines. Section five contains the same

specifications as they relate to the 4L engines. A broad range of component failures are

illustrated in section six. Non-L-Series specific service information on various topics is

placed in the appendix.

Due to the similarities between the 3L & 4L engines, we have created a single technician

guide to cover both engines. This training manual outlines the important aspects of the

repair manual; however, it is not a stand-alone manual. It must be used in conjunction

with the appropriate Workshop Manuals.

I. Introduction – Application Notes

UL-Series Diesel 2

The L series engines are used in a variety of

industrial applications ranging from small

generators (pictured here) and light duty farm

machinery to construction equipment. Their

compact design makes them an ideal power

system when conservation of space is of the

utmost consideration. Internally, both the 3L

and 4L engines share many similar parts. The

main difference between these engines is their

displacement and horsepower output.

Additionally, the 4L series has the option of

being turbocharged.

There are several L-series engines that are CARB (California Air Resource Board) certified.

CARB emissions standards for the L series apply to engine models in the 11-25 hp range and

25-50 hp range. To meet the new CARB standards, the pump’s injection timing has been

changed. This eliminates the cost of expensive emission control scrubbing devices. The

leaner fuel mixture (shorter injection duration) helps increase the exhaust temperatures while

lowering emissions at a fraction of the cost of scrubbing devices. Another feature unique to

Isuzu engines, is the conical shaped heat shield. This gives the incoming fuel injections a

“swirl affect” that increases atomizing for maximum combustion efficiency; this too helps

reduce exhaust emissions.

These are just some of the engineering refinements that Isuzu has implemented to stay

abreast with the latest in diesel and diesel emission technologies. In the ensuing pages, a

more thorough look at the internal components as well as fuel system will be covered.

I. Introduction – Maintenance Schedule

UL-Series Diesel 3

The following maintenance schedule is a comprehensive service program that takes a preventative

approach to engine repair. Isuzu has established these standards with maintenance as the basis for

prolonged product life. Isuzu highly recommends that if a routine maintenance schedule is not

part of your customer support service, one should be implemented to better serve the needs of

your customers.

Maintenance Item Daily 250 hrs 500 hrs 750 hrs 1000 hrs

Oil level 4

Oil leaks 4

Proper oil pressure 4

Low oil warning lamp 4

Oil filter replacement ¬4 4 4 4

Engine oil ¬4 4 4 4

Fuel leaks 4

Contaminated fuel 4

Fuel filter replacement 4 4

Injector nozzle check 4 4

Coolant level 4

Coolant leaks 4

Fan belt tension 4

Coolant temperature 4

Coolant replace Replace every 6 months

Electrolyte levels 4

Radiator fin cleaning 4

Radiator cap fitting check 4

Radiator cleaning 4

Radiator cap function test There is no service interval specification provided by Isuzu

Air cleaner check/replace Refer to element manufacturer for interval

Wire/Connector integrity There is no service interval specification provided by Isuzu

Battery charge % Refer to battery manufacturer or battery test tool for interval

Electrolyte gravity % Refer to battery manufacturer for interval

Starter cleaning 4

Generator cleaning 4

Battery cleaning 4

Pre-heat condition 4

Abnormal engine noises 4

Exhaust color 4

Cylinder compression 4

Valve lash check & set 4

¬Remove and replace after initial 50 hrs of engine operation. Then follow the regular

maintenance schedule thereafter.

I. Introduction – General Engine Family Information

UL-Series Diesel 4

L-Series Engines

Below is a brief description of the application/development criteria and design characteristics of the

L engine family:

Clean

•Individual Zexelinjection pumps w/short high pressure fuel injection pipes to reduce

volumetric loss and minimize injection delay common at high speeds.

•Ricardo Commet-V type combustion chamber

•Steel laminated head gasket and liquid gasket for other sealing surfaces means no more asbestos

•Blow-by gases recirculated into intake with use of PCV valve

Quiet

•Single OHV cam that drives injectors, intake and exhaust valves (less gear driven components)

•Large mesh area on gear driven components

•Auto-thermatic pistons that reduce engine noise at start up and after warm up.

Small size

•Overhead valve to reduce engine height

•Full siamese engine block design reduces length

Ease of Maintenance

•All service points of engine are placed on the same side

(oil fill, dipstick, filter, injection pumps, nozzles and glow plugs).

•Electric fuel pump purges air automatically

Identification

The production date for any Isuzu engine can be obtained be reading the letter codes on the ID tag

(usually located on the head cover) and using the table below.

ABC D EFG H IJ

0123456789

Example: BA/JB=10/91 (Engine produced October, 1991).

II. Engine Component Description

UL-Series Diesel 5

Pump Description

All L-series engines use individual injection pumps

to supply fuel to the injection nozzles. The fuel

pumps are mounted to the engine block, and are

operated by the camshaft. Inside of the pump, there

is a plunger barrel, timing sleeve, and plunger

assembly. The plunger barrel contains the pump’s

timing sleeve. The barrel uses a guide pin to locate

the timing sleeve in the correct position. The

internal area of the plunger barrel also serves as the

fuel reservoir. The timing sleeve fits over the

plunger and both components fit inside of the

plunger barrel

The timing sleeve component contains both the

fill port and the spill port. Fuel enters the

pressure chamber through the fill port. As the

plunger rises, it closes the fill and spill ports,

forcing pressurized fuel out the delivery valve to

the injector nozzle. Any residual fuel is bled off

through the spill port on the plunger return

stroke.

Pump timing is determined by the thickness of

shims placed between the pump housing and the

cylinder block. Each shim varies in thickness by

.1mm (.004”), creating a 1

change in timing

(thicker=retard, thinner=advance). The shims are

a “crush” design and must not be reused.

IMPORTANT: All pump shims must be of

the same thickness when replaced. No single

pump can have a different thickness shim

installed.

If this cannot be achieved, there could

be a problem with the injection pump. During

the warranty period, a pump requiring service

must

be returned to an authorized Zexel

distributor.

Timing SleevePlunger

Plunger

Barrel

Plunger Guide

II. Engine Component Description

UL-Series Diesel 6

Pump Timing

This drawing shows the relationship between cam lift and cam angle when pre-stroke length is

changed. The stroke length represented as “L” is always constant. When the pumps are advanced

by using a thinner shim, the timing sleeve is lowered and the start of injection occurs at the

beginning of the cam lift. (Note: the sleeve is fixed to the pump housing.)

Conversely, when the pump is retarded by using a thicker shim, the pre-stroke is lengthened

because the timing sleeve is raised. Raising the pump housing changes the start of injection to the

last half of the cam lift. It also reduces the total number of cam degrees to complete one injection.

Rack Operation

The plunger’s roller follower rides directly

on the cam lobe. Plunger position is

controlled by cam lobe lift. Rack movement

rotates the sleeve, changing the spill port

position relative to the plunger’s helix. This,

in turn, varies the amount of fuel injected.

NOTE: In order to remove the pumps from

the block, the rack slide must be centered

otherwise the pumps will hang-up on the

cylinder block casting.

II. Engine Component Description

UL-Series Diesel 7

Pump Injection Sequence

Intake

Fuel enters the high-pressure chamber

from the intake port. However, even

though the plunger begins to rise,

pressure inside the chamber does not

increase because the fuel from the inlet

port flows back into the fuel reservoir

via the spill-port hole

Beginning of Injection

As the plunger rises, it blocks the spill

port hole in the timing sleeve. The

plunger blocks the inlet port preventing

additional fuel from entering the high-

pressure chamber. It is during this

transition that pressure inside the

chamber begins to develop.

II. Engine Component Description

UL-Series Diesel 8

Pump Injection Sequence (continued)

Pressure Feeding

Since the intake port and helix are kept

closed by the timing sleeve, fuel

pressure continues to rise, the delivery

valve opens, and fuel flows to the

injector.

End of Injection

On the return stroke, when the plunger

helix reaches the timing sleeve’s spill

port, the pressurized fuel flows through

the spill port and into the oil reservoir.

At this moment pressure in the chamber

drops which ends the injection cycle.

II. Engine Component Description

UL-Series Diesel 9

Valve Train

IMPORTANT! Upon

reassembly, make certain

that all rocker springs are installed in their

correct location. Also ensure that the oil galley is

not blocked when applying liquid gasket.

L-series engines use individual rocker arms

mounted on a common shaft. The rockers and

shaft are mounted inside the rocker bracket

assembly. Both components can be removed

for servicing by simply removing the balance

shaft’s retaining plug at the rear of the bracket.

Before disassembly, note the positioning of the

left and right offset rocker arms. Off-setting

the rocker arms straightens out the push rod

angle. It also helps move the push rod end of

the rocker arm away from the bracket area to

eliminate rocker to bracket contact.

During disassembly, difficulties removing the

shafts may be experienced. This is due to the

slight interference fit in the bracket holes,

which may be compounded with varnish or

sludge build-up on the shaft.

NOTE: During reassembly, special care

must be taken to properly seal the rocker

bracket assembly. Since this is the intake

manifold, improper sealing will result in

excessive oil consumption.

The rocker shaft is oil pressure fed through a

galley machined in the cylinder head. This

galley intersects with the main oil galley in the

block to provide full pressure oiling to the

rocker arms.

Important: When replacing the head

gasket, be sure that the oil hole in the gasket

is aligned correctly with the oil galley in the

block. Failure to do so will prevent oil from

reaching the rocker shafts.

The head gasket is available in one thickness

only.

Do not seal oil galley

with liquid gasket.

Ce manuel convient aux modèles suivants

Table des matières

Autres manuels Isuzu Moteur

Isuzu

Isuzu c223 turbo Manuel d'instructions

Isuzu

Isuzu C-240PW-28 Manuel utilisateur

Isuzu

Isuzu 3CH1-NGZG01 Manuel de référence

Isuzu

Isuzu 3LD2 Manuel utilisateur

Isuzu

Isuzu AA-6HK1T Manuel d'instructions

Isuzu

Isuzu A-4BG1 Manuel d'instructions

Isuzu

Isuzu 4LE2 Manuel utilisateur

Isuzu

Isuzu 4JB1 Instructions d'utilisation et d'installation

Isuzu

Isuzu 4BB1 Manuel d'instructions

Isuzu

Isuzu C22NE Manuel d'instructions

Isuzu

Isuzu 4JJ1-TC Manuel utilisateur

Isuzu

Isuzu 25 Manuel utilisateur

Isuzu

Isuzu A-4JA1 Manuel d'instructions

Isuzu

Isuzu Trooper II 1986 Manuel utilisateur

Isuzu

Isuzu AU-4LE1T Manuel utilisateur

Isuzu

Isuzu 4LB1 Manuel d'instructions

Isuzu

Isuzu 4BG1 Manuel utilisateur

Isuzu

Isuzu 4BD1 Manuel d'instructions

Isuzu

Isuzu 4ja1 Manuel d'instructions

Isuzu

Isuzu 4HK-1 Manuel utilisateur

Isuzu

Isuzu 4LE2 Manuel d'instructions

Isuzu

Isuzu 4LE2 Manuel utilisateur

Isuzu

Isuzu NPR 4J Series Manuel d'instructions

Manuels Moteur populaires d'autres marques

Rotax

Rotax 125 senior MAX evo Manuel utilisateur

Kohler

Kohler K361 Manuel utilisateur

MTD

MTD OHV Series Manuel utilisateur

Kohler

Kohler COMMAND CH18-745 Manuel utilisateur

Mercury

Mercury D4.2L D-Tronic Manuel utilisateur

Selve

Selve SE Plus-RC Series Manuel utilisateur

Perkins

Perkins 1206E-E66TA Manuel utilisateur

Skov

Skov DA 174 Manuel

Rossi

Rossi TX11 Series Manuel utilisateur

Siemens

Siemens SIMOTICS T-1FW3 Feuille d'instructions

AL-KO

AL-KO PRO 350 Manuel utilisateur

MTU

MTU 12 V 4000 Lx4 Manuel utilisateur

Nanni

Nanni N3.30 Manuel d'instructions

Nanni

Nanni N5.160 CR2 Manuel utilisateur

KSB

KSB SuPreme Series Instructions d'installation

Hiwin

Hiwin EM1 Series Manuel utilisateur

Rotax

Rotax 912 i series Mode d'emploi

Siemens

Siemens SIMOTICS XP 1MB1 Manuel utilisateur