Doosan G424 Service Manual

SB2215E01

O c t . 2 0 0 1

Service Manual

G424 Gasoline/LP Engine

G424 LP Engine (Low Emission Version)

G20E-3, G25E-3, G30E-3

GC20E-3, GC25E-3, GC30E-3

Important Safety Information

Most accidents involving product operation, maintenance and repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs. A person must be alert to potential hazards. This person should also have the necessary training, skills and tools to perform these functions properly.

Read and understand all safety precautions and warnings before operating or performing lubrication, maintenance and repair on this product.

Basic safety precautions are listed in the “Safety” section of the Service or Technical Manual. Additional safety precautions are listed in the “Safety” section of the owner/operation/maintenance publication.

Specific safety warnings for all these publications are provided in the description of operations where hazards exist. WARNING labels have also been put on the product to provide instructions and to identify specific hazards. If these hazard warnings are not heeded, bodily injury or death could occur to you or other persons. Warnings in this publication and on the product labels are identified by the following symbol.

WARNING

Improper operation, lubrication, maintenance or repair of this product can be dangerous and could result in injury or death.

Do not operate or perform any lubrication, maintenance or repair on this product, until you have read and understood the operation, lubrication, maintenance and repair information.

Operations that may cause product damage are identified by NOTICE labels on the product and in this publication.

DAEWOO cannot anticipate every possible circumstance that might involve a potential hazard. The warnings in this publication and on the product are therefore not all inclusive. If a tool, procedure, work method or operating technique not specifically recommended by DAEWOO is used, you must satisfy yourself that it is safe for you and others. You should also ensure that the product will not be damaged or made unsafe by the operation, lubrication, maintenance or repair procedures you choose.

The information, specifications, and illustrations in this publication are on the basis of information available at the time it was written. The specifications, torques, pressures, measurements, adjustments, illustrations, and other items can change at any time. These changes can affect the service given to the product. Obtain the complete and most current information before starting any job. DAEWOO dealers have the most current information available.

1

Index

	GENERAL INFORMATION																		.......................................
																													4
	How to Read This Manual																				....................................
																													4
	Precaution Before Service																				....................................
																													6
	General		.................................................................
																													8
	Tightening Torque										.................................................
																													9
	Sealant	................................................................																											12
	SPECIFICATIONS						...................................................																						13
															..........................................
	General Specification																												13
															..........................................
	Service Specification																												14
	MAINTENANCE				......................................................																								17
																						................................
	Test Fuel System for Leaks																												17
	Check Engine Oil Level																	......................................											17
																									...........................
	Inspect Engine for Fluid Leaks																												17
	Change Engine Oil and Filter																							.............................					17
	Inspect Accessory Drive Belts ............................																												18
																				....................................
	Inspect Electrical System																												18
																										.........................
	Inspect Vacuum lines and fitting																												18
	Check Coolant Level													...........................................															18
																	........................................
	Inspect Coolant Hoses																												18
	Inspect Ignition System.......................................																												18
	Replace Spark Plug												............................................																18
																								.............................
	Replace LP fuel filter element																												19
	Test Fuelock (electric)															.........................................													19
																							...............................
	Replace Gasoline Fuel filter																												20
																							...............................
	Inspect Gasoline Carburetor																												20
																												................
	Inspect Pressure Regulator/Vaporizer																												20
																												................
	Inspect LP Mixer (Standard LP Truck)																												20
	Inspect Variable Venturi Air/Fuel Mxer
	(Low Emission LP Truck)																			....................................									20
	Inspect Complete Exhaust System for
	Leaks,damage					....................................................																							20
	Engine Control Unit (ECU) and others
	(Low Emission LP Truck)																			....................................									20
	Maintenance Schedule
																													21
	ENGINE SYSTEM						...................................................																						22
									.................................................
	Engine Overview																												22
	Timing System					....................................................																							25
																		......................................
	Silent Shaft Mechanism																												26
	Auto Lash Adjuster											..............................................																	27
																						................................
	Intake and Exhaust System																												28
	Electrical System									................................................																			30
	STARTING SYSTEM										...............................................																		32
													............................................
	General Description																												32
	Start Relay Test							..................................................																					35
	Start Motor			..........................................................																									36
					.......................................................
	Operation																												36
																							...............................
	Removal and Installation																												39
																											......................
	Disassembly and Reassembly																												42
	CHARGING SYSTEM											..............................................																	47
													............................................
	General Description																												47

	Alternator	............................................................											47
	IGNITION SYSTEM .................................................												50
	Breakerless Ignition System
													50
	Distributor
		............................................................							....................................				51
	Removal and Installation												54
	Distributor, disassembly and reassembly ...........												56
	GASOLINE FUEL SYSTEM								....................................				58
	General Description						............................................						58
	Geasoline Carburetor, Operation
													59
									....................................
	Removal and Installation												64
	Gasoline Carburetor
	Disassembly and Reassembly............................												66
	LPG FUEL SYSTEM ...............................................						............................................						73
	General Description												73
											..................................
	Electric Fuelock Model												73
	Converter		.......................................................										74
			.......................................................
	Fuel Tank												75
						..............................................
	LP Relief Valve												75
	Carburetor			.....................................................									76
								...........................................
	Tests or Adjustments												77
											..................................
	Carburetor Adjustment												77
												..............................
	Fuel System Leak Check												79
	Recommendation for LP Fuel System ..........												80
	LP Converter - Check, Clean ........................												81
	Disassembly and Assembly ................................												82
	LPG Carburetor
													82
	LP Gas Fuelock
													84
	LP Gas Converter..........................................												85
	LPG FUEL SYSTEM (LOW EMISSION VERSION)..87
	General Description						............................................						87
	LP Carburetor				................................................								89
										...................................
	Vacuum switch (MAP)												90
	Vacuum switch					..............................................							90
	LP Converter
													91
	Fuel Control Valve
													92
	Fuelock Valve				................................................								92
	Engine Control Unit (ECU)
													93
	Oxygen Sensor
						..............................................							94
	Catalytic Muffler
													95
	Tests or Adjustments
													96
	LP Carburetor - Check, Clean.......................												97
	LP Converter-Check,Clean ...........................												97
	Inspection of Fuelock Valve
													97
	Inspection of Fuel Control Valve
													97
	Inspection of Vacuum switch
													97
	Inspection of Vacuum switch (MAP)
													97
	Inspection of Oxygen sensor.........................												98

	Disassembly and Assembly	................................99
	LPG Carburetor
		99
	LP Gas Converter........................................	101

G424 Service Manual

2

Index

	DUAL FUEL SYSTEM							...........................................																				102
	GOVERNING SYSTEM									.........................................																		103
	General Description								..........................................																			103
																											..........
	Governor,Disassembly and Reassembly																											104
	LUBRICATION SYSTEM											.......................................																106
	General Description								..........................................																			106
											........................................
	Testing and Adjusting																											107
	Engine Oil					...............................................																						107
																								..................
	Lubrication System Problem																											107
	Oil Pressure Check															................................												109
	COOLING SYSTEM					...............................................
																												110
	General Description								..........................................
																												110
	Testing and Adjusting										........................................
																												111
	Cooling System Visual Inspection																								...............
																												111
	Cooling System Tests														..................................
																												111
	Thermostat		...................................................
																												113
	Cooling system Heat Problem																						.....................
																												114
	Cooling System Recommendation ..............																											114
	Belt Adjustment
							............................................																					116
	V-belt Diagnosis							...........................................
																												116
	Serivce Procedure						............................................
																												117
	Draining and Filling Cooling System																									...........
																												117
	Flushing the Cooling System																					.......................
																												118
	Radiator Service								..........................................																			118
	Removal & Install Water Temperature Sender..119
	BASE ENGINE SERVICE PROCEDURE .............																											120
		........................................................
	Timing Belt																											120
				.................................................
	Intake Manifold																											129
																								..................
	Exhaust Manifold and Water Pump																											130
	Rocker Arms and Camshaft																..............................											133
	Cylinder Head and Valves															................................												139
	Front Case and Oil Pan												....................................															145
																	..............................
	Piston and Connecting Rod																											154
																				.........................
	Crankshaft and Cylinder Block																											162
	ADJUSTMENT AND TROUBLESHOOTING ........169
	Adjustment	........................................................																										169
																				.........................
	Valve Clearnce Adjustment																											169
	Ignition Timing Adjustment																		..........................									169
	Idle Speed Adjustment															................................												171
	Air Governor Adjustment																	.............................										171
	Anti-Hunting Adjustment																..............................											171
	Troubleshooting				................................................																							172
	Engine Performance												....................................															172
	Engine Starting Problems
																					........................							172
	Charging System Problems																											173
	Instrument Problems													...................................														173
	Engine Noise					...............................................																						174
																		.............................
	Oil Pressure Diagnostics																											176
	Oil Pressure Problems															................................												177
	Water in Engine							...........................................																				178
												.......................................
	Engine Overheting																											179
	LP Fuel System
	(Standard and/or Low Emission Version)....																											180
	Troubleshooting Flow Chart																				........................							187

	General		..................................................		187
	Engine	....................................................			189
	Carburetor ..............................................				190
				...........................
	Electrical Components				192
	SPECIAL TOOLS		..................................................		195

G424 Service Manual

3

Index

GENERAL INFORMATION

How To Read This Manual

Scope of Explanation

This book describes the service procedures for the engine removed from the vehicle.

For procedures concerning removal of the engine from the vehicle and on-vehicle inspection and servicing, refer to the appropriate service manuals separately prepared for the individual models.

Maintenance and Servicing Procedures

(1) A diagram of the component parts is provided	• Removal steps:
near the front each section in order to give the	The part designation number corresponds to the
reader a better understanding of the installed	number in the illustration to indicate removal steps.
condition of component parts.
	• Installation steps:
(2) The numbers provided within the diagram	Specified in case installation impossible in reverse
indicate the sequence for maintenance and	order of removal steps. Omitted if installation is
servicing procedures; the symbol N indicates a	possible in reverse order of removal steps.
non-reusable part; the tightening torque is
provided where applicable.	• Disassembly steps:
	The part designation number corresponds to the number
	in the illustration to indicates disassembly steps.
	• Reassembly steps.
	Specified in case reassembly is impossible in
	reverse order of disassembly steps. Omitted if
	reassembly is possible in reverse order of
	disassembly steps.

Classification of Major Maintenance/Service points

When there are major points relative to maintenance and servicing procedures (such as essential maintenance and service points, maintenance and service standard values, information regarding the use of special tools, etc.), these are arranged together as major maintenance and service points and explained in detail.

A : Indicates that there are essential points for removal or disassembly. B : Indicates that there are essential points for installation or reassembly.

Symbols for Lubrication, Sealants and	following the component parts page, and
Adhesives	explained.
Information concerning the locations for
lubrication and for application of sealants and	.... Sealant or adhesive
adhesives if provided, by using symbols, in the
diagram of component parts, or on the page	.... Engine oil or gear oil

Inspection

Only the inspections to be performed by using special tools or measuring instruments are covered. General service procedures not covered in this manual, such as visual inspections and cleaning of parts, however, should always be performed during actual service operations.

G424 Service Manual

4

General Information

FRONT CASE AND OIL PAN

REMOVAL AND INSTALLATION

									6EN1898
			N	1.	Oil filter		H	17.	Oil pump case assembly
			M	2.	Oil pressure switch			18.	Front case gasket
				3.	Drain plug		G	19.	Oil pump cover
			L	4.	Drain plug gasket		G	20.	Oil pump drive gear
		A	K	5.	Oil pan		G	21.	Oil pump driven gear
				6.	Oil screen		F	22.	Crankshaft front oil seal
				7.	Oil screen gasket		E	23.	Oil pump oil seal
		B	J	8.	Plug		D	24.	Counterbalance shaft oil seal
				9.	O-ring			25.	Front case
		C	I	10.	Flang bolt			26.	Counterbalance shaft, left
				11. Relief plug				27.	Counterbalance shaft, right
				12.	Gasket	D	C	28.	Counterbalance shaft, front bearing
				13.	Relief spring	E	B	29.	Counterbalance shaft, rear bearing, left
				14.	Relief plunger	E	A	30.	Counterbalance shaft, rear bearing, right

15.Oil filter bracket

16.Oil filter bracket gasket

	REMOVAL SERVICE POINTS
MD998727	A Oil pan removal

(1)Remove the all oil pan bolts.

(2)Drive in the special tool between the cylinder block and oil pan.

(3)Side the tool by striking the edge of the special tool to separate the oil pan from the cylinder block.

6EN0698

This alphabetical letter corresponds to the one assigned to a part in the removal, installation, disassembly or reassembly steps that are indicated in the drawing on the first page of each section.

Operating procedures, cautions, etc. on removal, installation, disassembly and reassembly are described

G424 Service Manual

5

General Information

SEALANT

Precautions Before Servce

Removal and Disassembly

For prevention of wrong installation or reassembly and for ease of operation, put mating marks to the parts where no function is adversely affected.

1EN0018

Special Tool

Be sure to use Special Tools when their use is specified for the operation.

Use of substitute tools will result in malfunction of the part or damage it.

1EN0019

Tightening Torque

Tighten the part properly to specified torque.

1EN0020

Sealant

Use specified brand of sealant.

Use of sealant other than specified sealant may cause water or oil leaks.

1EN0021

G424 Service Manual

6

General Information

Replacement Part

When oil seal, O-ring, packing and gasket have been removed, be sure to replace them with new parts. However, rocker cover gasket may be reused if it is not damaged.

1EN0022

Rubber Parts

Do not stain timing belt and V-belt with oil or water. Therefore, do not clean the pulley and sprocket with detergent.

1EN0023

Oil and Grease

Before reassembly, apply specified oil to the rotating and sliding parts.

1EN0024

Genuine Part

When the part is to be replaced, be sure to use genuine part.

For selection of appropriate parts, refer to the Parts Catalog.

1EN0025

G424 Service Manual

7

General Information

General

Engine models and numbers

Engine model	Fuel type
G424	Gasoline, LPG, LPG (Low Emission Version)

Indication of engine model and number

The engine model and serial number are stamped on the right side of cylinder block surface.

Engine model	Engine number
4G64	AA0001 to YY9999

6EN1916

G424 Service Manual

8

General Information

Tightening Torque

Major Bolts and Nuts

	Item				Torque				Remarks
			kg•m		lb•ft		N•m
	Water pump pulley bolt		0.9		6.5		9
	Crankshaft pulley bolt		2.5		18.1		25
Ignition system	Spark plug		2.5		18.1		25
	Distributor nut		1.2		8.7		12
	Timing belt cover bolt		1.1		8.0		11
			0.9		6.5		9
	Tensioner spring spacer		4.9		35.4		48
Tensioner belt	Tensioner bolt		4.9		35.4		48
	Oil pump sprocket nut		5.5		39.8		54
	Crankshaft bolt		12.0		86.8		118
	Tensioner B bolt		1.9		13.7		19
	Counterbalance shaft		4.6		33.3		45
	Engine support bracket bolt		3.6		26.0		35
	Camshaft sprocket bolt		9.0		65.1		88
	Timing belt rear bolt		1.4		10.1		14
Fuel system	Carburetor nut		1.2		8.7		12
carburetor	Air horn nut		1.2		8.7		12
	Stud		1.2		8.7		12
	Fuel pump		1.1		8.0		11
Fuel system	LPG carburetor nut		1.2		8.7		12
LPG carburetor	Fuel pump cover		1.1		8.0		11
Intake manifold	Water outlet bolt		1.4		10.1		14
	Intake manifold bolt/nut		1.8		13.0		18
Exhaust	Oil level gauge guide bolt		1.4		10.1		14
manifold	Heat protector bolt		0.9		6.5		9
	Exhaust manifold nut		3.5		25.3		34
	Water inlet pipe bolt		1.4		10.1		14
	Water pump bolt		1.4		10.1		14
Rocker arm	Rocker cover bolt		0.6		4.3		6
		M8 B 25	2.4		17.4		24
and camshaft	Bearing cap bolt
		M6 B 65	2.0		14.5		20
Cylinder head,			8.0 kgf•m(57.9 lb•ft)[78 N•m]+ 0 +
valve	Cylinder head bolt		2.0 kgf•m(14.5 lb•ft)[20 N•m]+
				1/4 turn + 1/4 turn

G424 Service Manual

9

General Information

	Item			Torque			Remarks
			kg•m	lb•ft	N•m
	Drain plug		4.0	28.9	39
	Oil pan bolt		0.7	5.1	7
	Oil screen bolt/nut		1.9	13.7	19
	Oil pressure switch		1.0	7.2	10
Front case,	Plug		2.4	17.4	24
doil pan	Flange bolt		3.7	26.8	36
	Relief plug		45	32.5	44
	Oil filter bracket		1.9	13.7	19
	Oil pump cover bolt		1.7	12.3	17
	Oil pump cover screw		1.0	7.2	10
	Front case bolt		2.4	17.4	24
Piston,	Connecting rod bearing nut		2.0 kg•m(14.5 lb•ft) [20 N•m]+ 1/4 turn
connecting rod.
	Flywheel bolt		13.5	97.6	132
	Rear plate bolt		0.9	6.5	9
Crankshaft,
			6.0	43.4	59
cylinder block	Rear plate cover		1.1	8.0	11
	Oil seal case bolt		1.1	8.0	11
	Bearing cap bolt		2.0 kg•m(14.5 lb•ft) [20 N•m]+ 1/4 turn
Starter motor	Starter motor bolt		2.7	19.5	26

G424 Service Manual

10

General Information

General Bolts and Nuts Tightening Torque

Standard Bolts and Nuts

				Torque, kg•m (lb•ft) [N•m]
	Nominal
		Pitch	Bolt, stud, nut (with spring washer)			Flange bolt, flange nut
	diameter
			Head mark 4	Head mark 7	Head mark 10	Head mark 4	Head mark 7
	M5	M5	-	0.5 (0.5) [3.6]	-	-	0.6 (4.3) [5.9]
	M6	M6	-	0.9 (6.5) [8.8]	1.2 (8.7) [12]	-	1.0 (7.2) [9.8]
	M7	M7	1.2 (8.7) [12]	2.2 (15.9) [22]	3.0 (21.7) [29]	1.3 (9.4) [13]	2.4 (17.4) [24]
	M8	M8	2.5 (18.1) [25]	4.5 (32.5) [44]	6.0 (43.4) [59]	2.6 (18.8) [25]	5.0 (36.2) [49]
	M9	M9	4.2 (30.4) [41]	8.6 (60.0) [81]	10.7 (77.4) [105]	4.7 (34.0) [46]	9.5 (68.7) [93]
	M10	M10	7.3 (52.8) [72]	14.0 (101.3) [137]	14.5 (104.9) [142]	-	-

Tapered Threads

	Torque, kg•m (lb•ft) [N•m]
Size	Material of internal threads:		Material of internal threads:
	Aluminum alloy		Cast iron or steel
NPTF 1/16	0.5 to 0.8 (3.6 to 5.8)	[5 to 8]	0.8 to 1.2 (5.8 to 8.7) [8 to 11]
PT 1/8	0.8 to 1.2 (5.8 to 8.7) [8 to 11]		1.5 to 2.2 (10.8 to 15.9) [15 to 21]
PT 1/4	2.0 to 3.0 (14.5 to 21.7)	[20 to 29]	3.5 to 4.5 (25.3 to 32.5) [34 to 44]
NPTF 1/4	2.0 to 3.0 (14.5 to 21.7)	[20 to 29]	3.5 to 4.5 (25.3 to 32.5) [34 to 44]
PT 3/8	4.0 to 5.5 (28.9 to 39.8)	[39 to 59]	5.5 to 7.5 (39.8 to 54.2) [54 to 73]
PT 1/2	7.0 to 10.0 (50.6 to 72.3) [69 to 98]		12.0 to 16.0 (86.8 to 115.7) [118 to 156]

New Tightening Method-By Use of Bolts to be Tightened in Plastic Area

A new type of bolts, to be tightened in plastic area, is currently used in some parts of the engine. The tightening method for the bolts is different from the conventional one. Be sure to observe the method described in the text when tightening the bolts.

Service limits are provided for the bolts. Make sure that the service limits described in the text are strictly observed.

•Area where the bolts are in use:

(1)Cylinder head bolts

(2)Main bearing cap bolts

(3)Connecting rod cap bolts

•Tightening method

After tightening the bolts to the specified torque, tighten them another 90° or 180° (twice 90°). The tightening method varies on different areas. Observe the tightening method described in the text.

G424 Service Manual

11

General Information

Sealant

Part to be Applied	Brand
Semi circular packing	3MTM AAD Part No.8672 or equivalent
Rocker cover	3MTM AAD Part No.8672 or equivalent
Oil pressure switch	3MTM AAD Part No.8672 or equivalent
Oil pan	Silicone RTV sealant or eguivalent
Rear oil seal case	Silicone RTV sealant or eguivalent
Rear plate bolt	3MTM AAD Part No.8672 or equivalent
Oil seal case bolt	3MTM AAD Part No.8672 or equivalent

From in Place Gasket (FIPG)

The engine has several areas where the from-in-place gasket(FIPG) is in use. To ensure that gasket fully serves its purpose, it is necessary to observe some precautions when applying the gasket. Bead size, continuity and location are of paramount importance. Too thin a bead could cause leaks. Too thick a bead, on the other hand, could be squeezed out of location, causing blocking or narrowing of the fluid feed line. To eliminate the possibility of leaks from a joint, therefore, it is absolutely necessary to apply the gasket evenly without a break, while observing the correct bead size.

Since the FIPG used in the engine hardens as it reacts with the moisture in the atmospheric air, it is normally used in the metallic flange areas.

Disassembly

The parts assembled with the FIPG can be easily disassembled without use of a special method. In some cases, however, the sealant between the joined surfaces may have broken by lightly striking with a mallet or similar tool. A flat and thin gasket scraper may be lightly hammered in between the joined surfaces. In this case, however, care must be taken to prevent damage to the joined surfaces. For removal of the oil pan, the special tool “Oil Pan Remover” (MD998727) is available. Be sure to use the special tool to remove the oil pan.

Surface preparation

Thoroughly remove all substances deposited on the gasket application surfaces, using a gasket scraper or wire brush.

Check to ensure that the surfaces to which the FIPG is to be applied is flat. Make sure that there are no oils, greases and foreign substances deposited on the application surfaces. Do not forget to remove the old FIPG remaining in the bolt holes.

From-in-place gasket Application

Applied FIPG bead should be of the specified size and without breaks. Also be sure to encircle the bolt hole circumference with a completely continuous bead. The FIPG can be wiped away unless it is hardened. While the FIPG is still moist (in less than 15 minutes), mount the parts in position. When the parts are mounted, make sure that the gasket is applied to the required area only.

The FIPG application procedure may vary on different areas. Observe the procedure described in the text when applying the FIPG.

G424 Service Manual

12

General Information

SPECIFICATIONS

General Specifications

Item	Engine model			G424
Type				Water-cooled, 4-cycle, gasoline-powered and L.P.G.-powered
No. of cylinders and arrangement				4, in-line
Combustion chamber type				Semi-spherical
Valve mechanism				OHC
Total displacement, cm3(cc) [cu in.]				2350 (2350) [143]
Bore x stroke, mm (in.)				86.5 B 100 (3.41 B 3.94)
Dry weight, kg (lb)				146 (322)
Compression ratio				8.6
Compression pressure, kPa (kgf/cm2) [psi]				1128 (11.5) [163.5]
	Intake		Open	12° BTDC
Valve timing	valve		Close	40° ABDC
	Exhaust		Open	54° BBDC
	valve		Close	6° ATDC
Firing order				1 - 3 - 4 - 2
Ignition timing, BTDC/rpm				4°/740 (gasoline), 9°/740 (L.P.G.), 4˚/740(dual fuel)
Fuel pump			Gasoline	Mechanical (diaphragm type)
Carburetor				Down-draft type
Governor				Air flow type
Lubrication system				Pressure feed, full-flow filtration type
Oil pump				Gear, driven by timing belt
Oil filter				Filter paper, cartridge type
Cooling system				Water-cooled, forced circulation
Water pump				Centrifugal, driven by V-belt
Thermostat				Wax type
Electrical system				12V DC, negative ground
Alternator, (12V-61A)				Alternator current, built-in fan and regulator
Starter motor, (12V-1.2kW)				Reduction drive
Distributor				Equipped with automatic timing controller, breaker less type
Spark plug (NGK)			Gasoline	BPR4ES
			L. P. G.	BPR5ES
Quantity of lubricating oil, cm3 (liter) [U.S.gal]				4000(4.0) [1.06 ]( including 300 cm3(0.3 liter)[0.08 U.S.gal ]in oil filter
Quantity of coolant, cm3 (liter) [U.S.gal]				3100 (3.1) [0.82] (in engine proper)
IDLE RPM	LOW (RPM)			700 L 25
	HIGH (RPM)			2700 L 50

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Specifications

Service Specifications

								Unit : mm(in.)
			Item		Standard value		Limit	Remarks
	Flatness of gasket surface				0.03	(0.0012)
								Total resurfacing
	Grinding limit						0.2 (0.008)	depth of both
								cylinder head and
								cylinder block
head
	Overall height				89.9 to 90.1	(3.539 to 3.547)
Cylinder	Oversize rework			0.05 (0.0020)	13.05 to 13.07	(0.5138 to 0.5146)
	dimensions of valve			0.25 (0.0098)	13.25 to 13.27	(0.5217 to 0.5224)
	guide hole
				0.50 (0.0197)	13.50 to 13.57	(0.5315 to 0.5343)
	Oversize		Intake	0.30 (0.0118)	47.30 to 47.33	(1.8622 to 1.8634)
	rework
				0.60 (0.0236)	47.60 to 47.63	(1.8740 to 1.8752)
	dimensions of
			Exhaust	0.30 (0.0118)	40.30 to 40.33	(1.5866 to 1.5878)
	valve seat
	ring hole			0.60 (0.0236)	40.60 to 40.63	(1.5984 to 1.5996)
Camshaft	Cam height			Intake	41.62 (1.6386)		41.12 (1.6189)
				Exhaust	41.62 (1.6386)		41.12 (1.6189)
	Journal diameter				33.935 to 33.950 (1.33602 to 1.33661)
	Oil clearance				0.05 to 0.09 (0.0020 to 0.0035)
	Overall length			Intake	106.6 (4.197)		106.1 (4.126)
				Exhaust	105.2 (4.142)		104.7 (4.122)
	Valve stem projection				42.05 (1.6555)		42.55 (1.6752)
	Stem diameter			Intake	7.960 to 7.975 (0.31339 to 0.31398)
Valve				Exhaust	7.930 to 7.950 (0.31220 to 0.31299)
	Face angle				45° to 45.5°
	Thickness of valve			Intake	1.2	(0.047)
	head (margin)			Exhaust	2.0	(0.079)
	Stem-to-guide			Intake	0.025 to 0.058 (0.00098 to 0.00228)
	clearance			Exhaust	0.050 to 0.088 (0.00197 to 0.00346)
spring	Free height				48.0 (1.89)		47.0 (1.85)
Valve	Load/installed height				176.5N (18kg) [39.7lbf]/40.4 (1.591)
	Out-of-squareness				2° or less		4°
guide	Overall length			Intake	47 (1.85)
				Exhaust	52 (2.05)
Valve
	Inner diameter				8.000 to 8.018 (0.31496 to 0.31567)
seat	Valve contact width				0.9 to 1.3 (0.035 to 0.051)
Valve
	Sinkage						0.2 (0.008)
Piston	Outside diameter				86.47 to 86.50	(3.4043 to 3.4055)
	Piston clearance				0.02 to 0.04 (0.0008 to 0.0016)

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Specifications

							Unit : mm(in.)
	Item				Standard value	Limit	Remarks
ring	End gap			No. 1 ring	0.25 to 0.40 (0.0098 to 0.0157)	0.8 (0.031)
				No. 2 ring	0.45 to 0.60 (0.0177 to 0.0236)	0.8 (0.031)
Piston				Oil ring	0.20 to 0.60 (0.0079 to 0.0236)	1.0 (0.039)
	Ring-to-ring groove			No. 1	0.03 to 0.07 (0.0012 to 0.0028)
	clearance			No. 2	0.03 to 0.07 (0.0012 to 0.0028)
pin	Outside diameter				22.002 to 22.005 (0.86622 to 0.86634)
	Press-in load				7350 to 17160
Piston
	(at room temperature),				(750 to 1750)
	N (kg) [lbf]				[1650 to 3860]
rod	Big end center-to small end center				149.9 to 150.0 (5.902 to 5.906)
	length
Connecting
	Big end thrust clearance				0.10 to 0.25 (0.0039 to 0.0098)
	Bend				0.05 (0.0020)
	Twist				0.10 (0.0039)
	End play				0.05 to 0.18 (0.0020 to 0.0071)
	Journal outside diameter				56.982 to 57.000 (2.24338 to 2.24409)
Crankshaft	Pin Outside diameter				44.985 to 45.000 (1.77106 to 1.77165)
	Out-of-roundness and taper of				0.005 (0.00020)
	journal and pin
	Concentricity journal and pin				0.03 (0.0012)
	Oil clearance of journal				0.02 to 0.04 (0.0008 to 0.0016)
	Oil clearance of pin				0.02 to 0.05 (0.0008 to 0.0020)
block	Cylinder inner diameter				86.50 to 86.53 (3.4055 to 3.4067)
	Flatness of gasket surface				0.05 (0.0020)
Cylinder							Total resurfacing
	Grinding limit					0.2 (0.008)	depth of both
							cylinder head and
							cylinder block
	Overall height				289.9 to 290.1 (11.413 to 11.421)
Oil pump	Side clearance			Drive gear	0.08 to 0.14 (0.031 to 0.0055)
				Drive gear	0.06 to 0.12 (0.0024 to 0.0047)
Drive belt	Deflection			New belt	7.0 to 10.0 (0.28 to 0.39)
				Used belt	10 (0.39)
	Throttle bore diameter				32 (1.26)
	Outer venturi diameter				24 (0.94)
Carburetor	Inner venturi diameter				9 to 12 (0.35 to 0.47)
	Main jet (Symbol Size)				132.5
	Main air jet diameter				0.9 (0.035)
	Pilot jet diameter				0.55 (0.0217)
	Pilot air jet diameter				1.6 (0.063)
	Primary throtle valve to throtle				1.1(0.043)
	bore clearance

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15

Specifications

								Unit : mm(in.)
	Item					Standard value	Limit	Remarks
	Nominal output, kW					1.2
				Voltage, V		11.0
motor	No-load characterstics			Current, A		90 or less
				Speed, rpm		3000
Starter				Outer diameter		29.4 (1.16)	28.8 (1.13)
	Commutator			Runout		0.05 (0.0020)	0.1 (0.0039)
				Undercut		0.5 (0.020)	0.2 (0.008)
	Pinion gap					0.5 to 2.0 (0.020 to 0.079)
	Brush length						Wear limit line
Distributor	Centrifugal advance crank				Start	0°/1000
	angle/engine speed, °/rpm
					End	20°/5000
	Vacuum advance crank				End	0°/80
	angle/vacuum, °/mmHg
					Start	23°/280
n coil	Primary coil resistance, Ω					1.08 to 1.32
Ignitio
	Secondary coil resistance, Ω					22.1 to 29.9
plug	Plug gap					0.7 to 0.8 (0.028 to 0.031)
Spark
Tahermostat	Valve lift					8 (0.31) or more
	Valve opening temperature, °C (˚F)					82 (180)
	Fully opening temperature, ˚C (˚F)					95 (203)
	Oil Pressure			Low Idle		50 kPa(7psi)
				High Idle		450 kPa(65psi)

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Specifications

MAINTENANCE

G424 engine requires a certain amount of maintenance. Suggested maintenance requirements are contained in this section. The owner should, however, develop his own maintenance schedule using the requirements listed in this section and any other necessary requirements resulting from optional additions to the engine system.

Test Fuel System for Leaks

•Obtain a pump spray bottle.

•Fill with an approved leak test solution or a mixture of water and dish soap.

•Spray a generous amount of the solution on the entire fuel system including the fuel storage container and fuel lines.

•Wait approximately 15-60 seconds then perform a visual inspection of entire fuel system.

•Leaks will cause the soapy solution to bubble.

•Repair any leaks before continuing.

•Crank the engine through several revolutions. This will energize the fuel lock and allow fuel to flow to the pressure regulator/vaporizer. Apply additional leak test solution to this portion of the fuel system and inspect as above.

•Repair any fuel leaks before continuing.

1.Stop engine if in use.

2.Allow sufficient time (approximately 2 minutes) for the oil to drain back into the oil pan.

3.Remove dipstick. Wipe clean and reinstall. Push dipstick all the way into the dipstick tube.

4.Remove dipstick and note the oil level.

5.Oil level must be between the "MAX" and "MIN" marks.

6.If the oil level is below the "MIN" mark, proceed to Steps 7 and 8, and reinstall dipstick into the dipstick tube.

7.Remove oil filler cap from the valve rocker arm cover.

8.Add required amount of oil to bring level up to, but not over, the "MAX" mark on dipstick.

NOTE: When refill engine oil, refill same oil as that used before.

Check Engine Oil Level

IMPORTANT : Care must be taken when checking

engine oil level. Oil level must be main-tained between

the "MIN" mark and the "MAX" mark on the dipstick. To

ensure that you are not getting a false reading, make

sure the following steps are taken before checking the

oil level.

Inspect Engine for Fluid Leaks

•Start engine and bring up to operating temperature.

•Turn engine off.

•Inspect entire engine for oil and/or coolant leaks.

•Repair any/all leaks before continuing.

Change Engine Oil &Filter

•Start engine.

•Bring up to operating temperature.

•Shut down engine.

•Remove oil fill cap located in valve cover.

•Place drain pan under engine oil pan.

•Remove oil drain plug located at bottom of oil pan and allow engine oil to drain.

CAUTION : OIL WILL BE HOT.

•Remove engine oil filter. Make sure the oil filter gasket does not stick to engine.

CAUTION : OIL WILL BE HOT.

•Using a clean shop towel clean the engine oil filter gasket mating surface.

•Fill oil filter with engine oil.

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Maintenance

•Lube oil filter gasket with engine oil.

•Install oil filter as per filter manufacturers instructions. DO NOT OVER TIGHTEN

•Fill crankcase with engine oil.

•Start engine & run approximately 60 seconds.

•Shut down engine, wait approximately 2 - 5 minutes and then check oil level.

•When oil level is satisfactory start engine and check for any possible leaks.

•Repair any/all leaks before returning unit to service.

NOTE

Engine Oil Specification : See, Lubrication System section

Inspect Accessory Drive Belts

See, "Testing & Adjusting" of Cooling System Section.

Inspect electrical system

•Clean battery outer surfaces with a mixture of baking soda and water.

•Inspect battery outer surfaces for damage. Replace as required.

•Remove battery cables and clean.

•Inspect battery cables for worn or missing insulation, frayed wire and/or corrosion. Replace as required.

Inspect Vacuum Lines and Fittings

•Visually inspect vacuum lines and fittings for physical damage such as brittleness, cracks, kinks and misrouting. Repair/replace as required.

•Solvent damage may cause vacuum lines to become soft. Vacuum lines damaged by oil and/or other solvents may collapse when the engine is running effectively closing the passage inside the line.

Check Coolant Level

•Engine must be off and cold.

•NEVER REMOVE THE PRESSURE CAP ON A HOT ENGINE.

•The coolant level should be equal to the "COLD" mark on the coolant recovery tank. Periodically remove the cooling system pressure cap and check coolant level inside system. The coolant level should be equal to the sealing surface of the pressure cap. If level is low replace pressure cap and repair any/all other leaks.

•On closed systems visually inspect the coolant recovery tank and hoses for physical damage

•On open systems carefully remove cooling system pressure cap. Coolant level will be approximately 3040 mm below pressure cap sealing surface. If level is low replace pressure cap and repair any/all other leaks.

Inspect Coolant Hoses

•Visually inspect coolant hoses and clamps.

•Replace any hose that shows signs of swelling, cracking, abrasion hardening or any other damage/deterioration.

•Top-up cooling system with approved coolant.

Inspect Ignition System

•Remove and inspect spark plugs. Replace as required.

•Test secondary wires with an Ohmmeter. Maximum resistance repair replace as required.

•Remove distributor cap and perform visual inspection of distributor cap and rotor. Replace cap & rotor if corrosion is found on contacts.

•Inspect distributor breaker unit and housing for signs of corrosion. Repair replace as required.

Replace Spark Plugs

•Utilizing a gentle twisting motion remove the secondary high voltage leads from the spark plugs. Replace any damaged leads.

•Remove the spark plugs.

•Gap new spark plugs to proper specs.

•Apply anti-seize compound to spark plug threads.

•Install spark plugs.

•Do not over tighten.

•Install secondary high voltage leads.

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Maintenance

Replace LP Fuel Filter Element

Park the lift truck in an authorized refueling area with the forks lowered, parking beake applled and the transmission in NEUTRAL.

1.Close the fuel shutoff valve on the LP-Gas tank. Run the engine until fuel in the line runs out and the engine stops. Turn off the ignition switch and disconnect switch (if equipped).

2. Scribe a line across the filter housing covers.

3.Remove the cover retaining screws.

5	3	2	1
4

6

4.Remove cover (5), magnet (4), spring (3) and filter element (2) from bottom cover (1).

5.Replace the filter element (2).

6.Check bottom cover O-ring seal (6) for damage. Replace it if necessary.

7.Install the filter element (2), spring (3), magnet

(4)and cover (5) on bottom cover (1). Align the scribe line on the covers.

8.Install the cover retaining screws. Tighten the screws in a sequence opposite each other.

9.Open the fuel valve by slowly turning the valve counterclockwise.

10.Crank the engine only enough to produce a vacuum at the fuelock. Turn the ignition key switch off.

11.Check the fuel lines and fittings for leaks with a soap solution. Make repairs if necessary.

Test Fuel Lock (Electric)

•Start engine.

•Locate electrical connector for fuel lock.

•Disconnect electrical connector.

•Engine will run out of fuel and stop in a short period of time. (The length of time increases with any increase in distance between the fuel lock and the pressure regulator).

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Maintenance

Replace Gasoline Fuel Filter

(Gasoline Truck and Dual

Fuel Truck)

WARNING

Fuel leaked or spilled onto hot surfaces or electrical components can cause a fire.

Turn the disconnect switch OFF if fitted or disconnect the battery when changing fuel filters

1 3

2

1. Raise the hood and seat assembly.

2. Loosen Bolt(1) and clamps(2)(3).

3. Replace old fuel filter with new filter.

4. Fasten Bolt(1) and clamps(2)(3).

Inspect Gasoline Carburetor

See, gasoline carburetor in Gasoline fuel system section.

Inspect Pressure

Regulator/Vaporizer

See, pressure regulator/vaporizer in LP fuel system section.

Inspect LP Mixer

(Standard LP Truck)

See, LP mixer in LP fuel system section.

Inspect Variable Venturi

Air/Fuel Mixer

(Low Emission LP Truck)

See, Variable Venturi Air/Fuel Mixer in LP fuel system(Low emission version) section.

Inspect Complete Exhaust System for Leaks, Damage

•Perform visual inspection of exhaust system.

•Repair any/all leaks found.

Engine Control Unit(ECU) and others

(Low Emission LP Truck)

The commander, oxygen sensor and vacuum control solenoid are not serviceable. If faulty, they must be replaced. See Trouble Shooting Section

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Maintenance

Maintenance Schedule

				Interval Hours
			Every	Every	Every	Every	Every
	CHECK POINT	Daily	250hrs	500hrs	1000hrs	2000hrs	1000hrs
			or	or	or	or	or
			a month	3 months	6 months	a year	18 months
	General Maintenance Section
	Test fuel system for leaks	Prior to any service of maintenance activity
	Inspect engine for fluid leaks	O
	Check engine oil and filter	O
	Change engine oil and filter		O
	Inspect accessory drive belts				O
	Inspect electrical system					O
	Inspect all vacuum lines and fittings					O
	Inspect all fuel fittings and hoses					O
	Replace timing belt and counter balance shaft belt.						O
	Check engine compression pressure						O
	Engine Coolant Section
	Check coolant level	O
	Change coolant					O
	Inspect coolant hoses for leaks, cracks swelling, or deterioration				O
	Engine Ignition Section
	Inspect battery for case damage and corroded Cables					O
	Inspect ignition system				O
	Check ignition timing-adjust as necessary					O
	Replace spark plugs					O
	Fuel Lock-Off/Filter Section
	Replace LP fuel filter element				O
	Replce gasoline fuel filter					O
	Inspect lock-off and filter for fuel leaks					O
	Ensure lock-off stops fuel flow when engine is off					O
	Pressure Regulator Section
	Test regulator pressures					O
	Inspect pressure regulator for oil build-up					O
	Inspect pressure regulator assembly for fuel/coolant leaks					O
	Carburetor Section
	Check for air leaks in filter system					O
	Check for vacuum leaks on complete intake system					O
	Inspect air/gas valve assembly			O
	Inspect air/fuel mixture throat			O
	Inspect gasoline carburetor				O
	Check air cleaner indicator	O
	Inspect air cleaner		O
	Replace air filter element					O
	Engine Exhaust Section (Low Emission Version only)
	Inspect exhaust manifold for leaks					O
	Inspect manifold-to-catalyst exhaust piping and Connections for leaks					O
	Inspect catalyst inlet and outlet and leaks					O

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Maintenance

ENGINE SYSTEM

Engine Overview

The cylinder blocks are made of the special cast iron and employ 5-bearing, deep skirt system.

The cylinder heads have hemisphere combustion chambers, are of cross flow type arranged with V-type valves and high efficient combustion is intended.

The camshaft is located on the top of the cylinder heads and driven by cog type timing belt.

Dual type exhaust manifold is employed in order to reduce output loss by exhaust interference.

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Engine System

Gasoline Engine

G424 Service Manual

23

Engine System

LPG Engine ( Low Emission Version)

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24

Engine System

Timing System

The timing belt is meshed with the sprockets, the crankshaft sprocket becomes the drive sprocket, and thus functions to drive the camshaft and oil pump.

Timing belt

The timing belt is the cogged type, using rubber as its basic material, and it employs a high-strength glass fiber core which does not expand or contract.

The features of the cogged-type belt compared to a chin are no expansion/contraction, low noise level, no necessity for lubrication, light weight, etc.

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Engine System

Silent Shaft Mechanism

The silent shaft mechanism function mainly to eliminate, by the action of the silent shafts incorporated at both sides of the cylinder block, the vertical vibromotive force of the engine as well as the vibromotive moment in the rolling direction, thus making possible quieter operation of the vehicle.

The two silent shafts are arranged as shown in the

figure below. The right silent shaft rotates in the same direction as the crankshaft, and the left silent shaft rotates in the opposites direction. Both of these silent shafts rotate at speed twice that of the crankshaft.

Right silent shaft is driven by timing belt B, and the left silent shaft is driven by drive gear.

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Engine System

Auto Lash Adjuster

Construction

These engines have auto lash adjusters that eliminate the need for valve clearance adjustment and reduce noises of the valve system. The auto lash adjuster automatically absorbs change in the valve clearance caused by engine temperature change or wear of parts and adjusts the valve clearance always to zero.

Operation of Auto Lash Adjuster

(1)At Start of Valve Lift

When the cam lifts up the rocker arm, the hydraulic pressure immediately forces the ball in the high pressure chamber against the seat, closing the high pressure chamber.

(2)During Valve Lift

A small amount of oil leaks from the high pressure chamber through a clearance between the body inside and the plunger outside.

(3)At end of Valve Lift

The plunger spring forces the body back to the initial position and oil is supplied to the high pressure chamber to make up for the leaked oil.

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Engine System

Intake and Exhaust System

Gasoline Engine

The intake manifold employs the shape having good intake performance.

The exhaust manifold employs a dual type and intend the reduction of output loss due to exhaust interference.

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Engine System

LPG Engine (Low Emission Version)

G424 Service Manual	29	Engine System