Page 2 Information contained in this Workshop Manual is the latest available at the time of publication. Isuzu reserves the right to make changes at any time without prior notice. This Workshop Manual is applicable to 1998 and later models.
Page 3: Table Of Contents
TABLE OF CONTENTS SECTION 1. GENERAL INFORMATION........SECTION 2.
Page 4: Section 1. General Information
GENERAL INFORMATION SECTION 1 GENERAL INFORMATION TABLE OF CONTENTS ITEM PAGE General repair instructions ............Notes on the format of this manual .
Page 5: General Repair Instructions
11. Always check and recheck your work. No service operation is complete until you have done this. NOTES ON THE FORMAT OF THIS MANUAL This Workshop Manual is applicable to ISUZU industrial engine or engines which is or are stated in the title.
Page 6 GENERAL INFORMATION 4. When the same servicing operation is applicable to several different units, the manual will direct you to the appropriate page. 5. For the sake of brevity, self-explanatory removal and installation procedures are omitted. More complex procedures are covered in detail. 6.
Page 7: General Information
Important operation requiring extra care ..Reassembly ..Specified torque (tighten) Special tool use required or ..Alignment (marks) ..recommended(Isuzu tool or tools) Commercially available tool use ..Directional indication ..required or recommended ..Inspection ..Lubrication (oil) ..
Page 8 GENERAL INFORMATION 9. Measurement criteria are defined by the terms "standard" and "limit". A measurement falling within the "standard" range indicates that the applicable part or parts are serviceable. "Limit" should be thought of as an absolute value. A measurement which is outside the "limit" indicates that the applicable part or parts must be either repaired or replaced.
Page 9: Main Data And Specifications
GENERAL INFORMATION MAIN DATA AND SPECIFICATIONS Engine Model A-4JA1 A-4JB1 4JB1T Item Engine type Water cooled, four-cycle, in-line, overhead valve Combustion chamber type Direct injection Cylinder liner type No. of cylinders - Bore x Stroke mm(in.) 4 - 93.0 x 92.0 4 - 93.0 x 102.0...
Page 10: Tightening Torque Specifications
GENERAL INFORMATION TIGHTENING TORQUE SPECIFICATIONS The tightening torque values given in the table below are applicable to the bolts unless otherwise specified. STANDARD BOLT kgf·m (lb.ft/N·m) Strength 4.8 (4T) 9.8 (9T) (7T) Class Refined Non-Refined Bolt Identification Bolt No mark Diameter ×...
Page 11: Tightening Torque Specifications
GENERAL INFORMATION TIGHTENING TORQUE SPECIFICATIONS The tightening torque values given in the table below are applicable to the bolts unless otherwise specified. FLANGED HEAD BOLT kgf·m (lb.ft/N·m) Bolt head marking Nominal size (dia. x pitch) 0.5 – 0.9 0.6 – 1.2 M 6 ×...
Page 12 GENERAL INFORMATION SPECIAL PARTS FIXING NUTS AND BOLTS Cylinder Head Cover, Cylinder Head, and Rocker Arm Shaft Bracket kgf·m(lb.ft./N·m) 0.8 – 1.8 (5.8 – 13.0/7.8 – 17.6) 5.0 – 6.0 (36.2 – 43.4/49.0 – 58.8) 1.0 – 2.0 (7.2 – 14.4/9.8 – 19.6) 1st Step 2nd Step 3.0 –...
Page 13 GENERAL INFORMATION Crankshaft Bearing Cap, Connecting Rod Bearing Cap, Crankshaft Damper Pulley, Flywheel, and Oil Pan kgf·m(lb.ft./N·m) 11.5 – 12.5 (83.2 – 90.4/112.8 – 122.6) 8.0 – 9.0 (57.9 – 65.1/78.4 – 88.2) 16.0 – 18.0 (115.7 – 130.2/159.6 – 176.5) 20.1 –...
Page 14 GENERAL INFORMATION Timing Gear Case, Flywheel Housing, Camshaft, and Timing Gear kgf·m(lb.ft./N·m) M10 x 1.25 (0.39 x 0.05) 4.6 – 6.6 (33.3 – 47.7/45.1 – 64.7) M12 x 1.25 (0.47 x 0.05) 9.6 – 11.6 (69.4 – 83.9/94.1 – 113.8) M12 x 1.75 (0.47 x 0.07) 8.8 –...
Page 15 GENERAL INFORMATION Cooling and Lubricating System kgf·m(lb.ft./N·m) 1.4 – 2.4 (10.1 – 17.3/13.7 – 23.5) 1.4 – 2.4 (10.1 – 17.3/13.7 – 23.5) 1.4 – 2.4 (10.1 – 17.3/13.7 – 23.5) 1.4 – 2.4 (10.1 – 17.3/13.7 – 23.5) 1.4 – 2.4 (10.1 –...
Page 16 GENERAL INFORMATION Intake and Exhaust Manifold kgf·m(lb.ft./N·m) 1.4 – 2.4 (10.1 – 17.3/13.7 – 23.5) 1.4 – 2.4 (10.1 – 17.3/13.7 – 23.5)
Page 17 GENERAL INFORMATION Engine Electrical kgf·m(lb.ft./N·m) 2.0 – 2.5 1.4 – 2.4 (14.4 – 18.1/19.6 – 24.5) (10.1 – 17.3/13.7 – 23.5) 3.6 – 4.6 (26.0 – 33.3/35.3 – 45.1) 6.0 – 8.0 (43.4 – 57.9/58.8 – 78.4)
Page 18 GENERAL INFORMATION Fuel Injection System kgf·m(lb.ft./N·m) 20 – 4.0 (14.4 – 28.9/19.6 – 39.2) 3.2 – 4.4 (23.1 – 31.8/31.4 – 43.2) 1.4 – 2.4 (10.1 – 17.3/13.7 – 23.5) 1.4 – 2.4 (10.1 – 17.3/13.7 – 23.5) 1.4 – 2.4 (10.1 –...
Page 19 MEMO...
Page 20: Section 2. Maintenance
MAINTENANCE SECTION 2 MAINTENANCE TABLE OF CONTENTS ITEM PAGE Model identification ............. 18 Injection pump identification .
Page 21 Use of the wrong service data will result in reduced engine performance and engine damage. 1 ZEXEL (Manufacturer of the injection pump) identifi- cation number 2 ISUZU Parts Number Distributor type LUBRICATING SYSTEM Main Oil Filter Replacement Procedure 1.
Page 22 MAINTENANCE 4. Clean the oil cooler fitting face. This will allow the new oil filter to seat properly. 5. Apply a light coat of engine oil to the O-ring. 6. Turn in the new oil filter until the filter O-ring is fitted against the sealing face.
Page 23 MAINTENANCE Water Separator (Water Sedimentor) (Optional Equipment) Check the water separator float 1 level. If the float 1 has reached level 2 , loosen the drain plug 3 (at the bottom side of the water separator) to drain the water. Drain Plug Torque kgf·m(lb.ft./N·m) 0.9 –...
Page 24 MAINTENANCE Injection Nozzle Injection Nozzle Inspection Use a nozzle tester to check the injection nozzle opening pressure and the spray condition. If the opening pressure is above or below the specified value, the injection nozzle must be replaced or recondi- tioned.
Page 25: Cooling System
MAINTENANCE COOLING SYSTEM Cooling Fan Drive Belt Fan belt tension is adjusted by moving the alternator. A Crankshaft damper pulley B Alternator pulley C Cooling fan drive pulley D Depress the drive belt mid-portion with a 10 kgf (22 lb/98 N) force. Drive Belt Deflection mm(in.) 10.0 (0.39)
Page 26: Valve Clearance Adjustment
MAINTENANCE VALVE CLEARANCE ADJUSTMENT 1. Retighten the rocker arm shaft bracket bolts in sequence as shown in the illustration. Rocker Arm Shaft Bracket Bolt Torque kgf·m(lb.ft/N·m) 5.0 – 6.0 (36.2 – 43.4/49.0 – 58.8) 2. Bring the piston in either the No. 1 cylinder or the No.
Page 27: Injection Timing
MAINTENANCE Rotate the crankshaft 360°. Realign the crankshaft damper pulley TDC line with the timing pointer. Adjust the clearances for the remaining valves as shown in the illustration. (At TDC on the compression stroke of the No. 4 stroke) INJECTION TIMING Injection Timing Confirmation Procedure In-line type injection pump 1) Rotate the crankshaft clockwise to align the cam-...
Page 28 MAINTENANCE Distributor type injection pump 1) Rotate the crankshaft clockwise to align the cam- shaft gear timing mark “O” with the timing gear case cover pointer. The No. 1 cylinder will now be at the point where nearly injection timing. 2) Remove injector pump distributor head plug.
Page 29 MAINTENANCE COMPRESSION PRESSURE MEASUREMENT 1. Start the engine and allow it to run for several minutes to warm it up. 2. Stop the engine and cut the fuel supply. 3. Remove all of the glow plugs from the engine. Compression Gauge :5-8840-2675-0 Adapter :5-8840-9029-0 4.
Page 30 MAINTENANCE RECOMMENDED LUBRICANTS ENGINE TYPE TYPES OF LUBRICANTS Diesel engine oil Without turbocharger CC or CD grade Diesel engine oil With turbocharger CD grade ENGINE OIL VISCOSITY CHART ENGINE OIL VISCOSITY GRADE – AMBIENT TEMPERATURE [Single grade] SAE 40 SAE 20, 20W SAE 10W SAE 30 Ambient...
Page 31: Engine Repair Kit
MAINTENANCE ENGINE REPAIR KIT All of the numbered parts listed below are included in the Engine Repair Kit. The gaskets marked with an asterisk (*) are also included in the Top Overhaul Kit. 1. Cylinder head gasket 11. Water pump gasket 2.
Page 32: Section 3. Engine Assembly (1)
ENGINE ASSEMBLY ( 1 ) SECTION 3 ENGINE ASSEMBLY ( 1 ) TABLE OF CONTENTS ITEM PAGE General description ............. . 30 Disassembly .
Page 33: Engine Assembly
GENERAL DESCRIPTION This illustration is based on the A-4JA1 engine. The A-4J Series of industrial engines features the unique ISUZU troidal square combustion chamber. This design provides superior fuel economy for a wide range. Auto-thermatic pistons with cast steel struts are used to reduce thermal expansion and resulting engine noise when the engine is cold.
Page 34 ENGINE ASSEMBLY ( 1 ) DISASSEMBLY These disassembly steps are based on the A-4JA1 engine. 7 8 5 Disassembly Steps - 1 1. Cooling fan and spacer 11. Fuel leak off pipe 2. Cooling fan drive belt 12. Fuel injection pipe with clip 3.
Page 35 ENGINE ASSEMBLY ( 1 ) Important Operations (Disassembly Steps - 1) 12. Fuel Injection Pipe with Clip Loosen the injection pipe sleeve nuts at the delivery valve side. Do not apply excessive force to the injection pipes. Loosen the injection pipe clips. Remove the injection pipes.
Page 36 ENGINE ASSEMBLY ( 1 ) ★ ★ ★ ★ ★ ★ ★ Repair kit Disassembly Steps - 2 1. Water by-pass hose 10. Cylinder head gasket 2. Thermostat housing 11. Crankshaft damper pulley with 3. Water pump dust seal 4. Injection nozzle holder 12.
Page 37 ENGINE ASSEMBLY ( 1 ) ★ ★ ★ Repair kit Disassembly Steps - 3 1. Oil pan 9. Piston and connecting rod with 1a. Oil pan (If so crankcase equipped) upper bearing 2. Crankcase (If so equipped) 10. Crankshaft bearing cap with 3.
Page 38 ENGINE ASSEMBLY ( 1 ) Important Operations (Disassembly Steps - 2) 4. Injection Nozzle Holder Remove the nozzle holder bracket nuts. Use the nozzle holder remover and the sliding hammer to remove the nozzle holder together with the holder bracket. Nozzle Holder Remover: 5-8840-2034-0 Sliding Humme: 5-8840-0019-0 7.
Page 39 ENGINE ASSEMBLY ( 1 ) 11. Crankshaft Damper Pulley with Dust Seal Block the flywheel with a piece of wood to pre- vent it from turning. Use the damper pulley remover to remove the damper pulley. Damper Pulley Remover 16. Idler Gear “A” Measure the camshaft timing gear backlash, the crankshaft timing gear backlash, and the idler gear “A”...
Page 40 ENGINE ASSEMBLY ( 1 ) Important Operations (Disassembly Steps - 3) 3. Flywheel Block the flywheel with a piece of wood to pre- vent it from turning. Loosen the flywheel bolts a little at a time in the numerical order shown in the illustration. 6.
Page 41 ENGINE ASSEMBLY ( 1 ) 10. Crankshaft Bearing Cap with Lower Bearing 1) Measure the crankshaft end play at the center journal of the crankshaft. Do this before removing the crankshaft bearing caps. If the measured value exceeds the specified limit, the crankshaft thrust bearing must be replaced.
Page 42 ENGINE ASSEMBLY ( 1 ) DISASSEMBLY SINGLE UNIT ROCKER ARM SHAFT AND ROCKER ARM Disassembly Steps 1. Rocker arm shaft snap ring 5. Rocker arm shaft spring 2. Rocker arm 6. Rocker arm shaft snap ring 3. Rocker arm shaft bracket 7.
Page 43 ENGINE ASSEMBLY ( 1 ) Important Operations 1. Rocker Arm Shaft Snap Ring 2. Rocker Arm 3. Rocker Arm Shaft Bracket Use a pair of snap ring pliers to remove the snap rings. Remove the rocker arms. Remove the rocker arm shaft bracket. If the rocker arms and rocker arm shaft brackets are to be reinstalled, mark their installation positions by tagging each rocker arm and rocker...
Page 44 ENGINE ASSEMBLY ( 1 ) CYLINDER HEAD Disassembly Steps 1. Split collar 5. Valve stem oil seal 2. Valve spring upper seat 6. Valve spring lower washer 3. Valve spring 7. Cylinder head 4. Intake and exhaust valves...
Page 45 ENGINE ASSEMBLY ( 1 ) Important Operations 1. Split Collar Place the cylinder head on a flat wooden surface. Use the spring compressor to remove the split collar. Do not allow the valve to fall from the cylinder head. Spring Compressor: 9-8523-1423-0 4.
Page 46 ENGINE ASSEMBLY ( 1 ) PISTON AND CONNECTING ROD Disassembly Steps 1. Connecting rod bearing 5. Connecting rod 2. Piston ring 6. Piston pin snap ring 3. Piston pin snap ring 7. Piston 4. Piston pin...
Page 47 ENGINE ASSEMBLY ( 1 ) Important Operations 1. Connecting Rod Bearing If the connecting rod bearings are to be reinstalled, mark their fitting positions by tagging each bearing with the cylinder number from which it was removed. 2. Piston Ring Clamp the connecting rod in a vise.
Page 48 ENGINE ASSEMBLY ( 1 ) CAMSHAFT, CAMSHAFT TIMING GEAR, AND THRUST PLATE Disassembly Steps 1. Camshaft timing gear 3. Feather key 2. Thrust plate 4. Camshaft...
Page 49 ENGINE ASSEMBLY ( 1 ) Important Operations 1. Camshaft Timing Gear 2. Thrust Plate Clamp the camshaft in a vise. Take care not to damage the camshaft. Use the universal puller 1 to pull out the camshaft timing gear 2 . Universal Puller: 5-8840-0086-0 Remove the thrust plate 3 .
Page 50 ENGINE ASSEMBLY ( 2 ) SECTION 4 ENGINE ASSEMBLY ( 2 ) TABLE OF CONTENTS ITEM PAGE Inspection and repair ............48...
Page 51 ENGINE ASSEMBLY ( 2 ) INSPECTION AND REPAIR Make the necessary adjustments, repairs, and part replacements if excessive wear or damage is discovered during inspection. CYLINDER HEAD Cylinder Head Lower Face Warpage 1. Use a straight edge and a feeler gauge to measure the four sides and the two diagonals of the cylinder head lower face.
Page 52: Valve Guide
ENGINE ASSEMBLY ( 2 ) Manifold Fitting Face Warpage mm (in) Maximum Grinding Standard Limit Allwance 0.05 0.2 (0.008) 0.4 (0.016) (0.002) or less VALVE GUIDE Valve Stem and Valve Guide Clearance Measuring Method - I 1. With the valve stem inserted in the valve guide, set the dial indicator needle to “0”.
Page 53: Valve And Valve Seat Insert
ENGINE ASSEMBLY ( 2 ) Valve Guide Installation 1. Apply engine oil to the valve guide outer circumfer- ence. 2. Attach the valve guide replacer to the valve guide. 3. Use a hammer to drive the valve guide into position from the cylinder head upper face.
Page 54 ENGINE ASSEMBLY ( 2 ) Valve Depression 1. Install the valve 1 to the cylinder head 2 . 2. Use a depth gauge or a straight edge with steel rule to measure the valve depression from the cylinder head lower surface. If the measured value exceeds the specified limit, the valve seat insert must be replaced.
Page 55 ENGINE ASSEMBLY ( 2 ) 3. Use a screwdriver 3 to pry the valve seat insert free. Take care not to damage the cylinder head 4 . 4. Carefully remove carbon and other foreign material from the cylinder head insert bore. Valve Seat Insert Installation 1.
Page 56: Valve Spring
ENGINE ASSEMBLY ( 2 ) 3. Apply abrasive compound to the valve seat insert surface. 4. Insert the valve into the valve guide. 5. Turn the valve while tapping it to fit the valve seat insert. 6. Check that the valve contact width is correct. 7.
Page 57 ENGINE ASSEMBLY ( 2 ) ROCKER ARM SHAFT AND ROCKER ARM Rocker Arm Shaft Run-Out 1. Place the rocker arm shaft on a V-block. 2. Use a dial indicator to measure the rocker arm shaft central portion run-out. If the run-out is very slight, correct the rocker arm shaft run-out with a bench press.
Page 58 ENGINE ASSEMBLY ( 2 ) 3. Check that the rocker arm oil port is free of obstruc- tions. If necessary, use compressed air to clean the rocker arm oil port. Rocker Arm Correction Inspect the rocker arm valve stem contact surfaces for step wear 1 and scoring 2 .
Page 59 ENGINE ASSEMBLY ( 2 ) Cylinder Body Height (Reference) mm(in) Standard 247.945 – 248.105 (9.7616 – 9.7679) 4. Reinstall the cylinder liner. Refer to “Cylinder Body Bore Measurement”. 5. Reinstall the cylinder body dowel. Cylinder Liner Bore Measurement Use a cylinder indicator to measure the cylinder bore at measuring point 1 in the thrust X –...
Page 60 (from the lower side of the cylinder body) unit it makes firm contact with the cylinder liner. Cylinder Liner Remover: 5-8840-2039-0 (A-4JA1, A-4JB1) 2. Use a bench press 2 to slowly force the cylinder liner from the cylinder body.
Page 61 ENGINE ASSEMBLY ( 2 ) Cylinder Liner Installation 1. Cylinder Liner Installation Using The Special Tool. 1) Use new kerosene or diesel oil to thoroughly clean the cylinder liners and bores. 2) Use compressed air to blow-dry the cylinder liner and bore surfaces. Note: All foreign material must be carefully removed from the cylinder liner and the cylinder bore before installation.
Page 62 ENGINE ASSEMBLY ( 2 ) WARNING: DRY ICE MUST BE USED WITH GREAT CARE. CARE- LESS HANDLING OF DRY ICE CAN RESULT IN SEVERE FROSTBITE. Piston Selection Select the same grade number as the one for the cylinder liner inside diameter. Grade of cylinder Grade of piston Combination...
Page 63 Calculate the average value of the eight measure- ments to determine the correct cylinder liner bore. Measuring Points 1 : 20 mm (0.79 in) for all A-4J models 2 : 140 mm (5.51 in) for A-4JA1 160 mm (6.30 in) for A-4JB1 Cylinder Liner Bore...
Page 64 ENGINE ASSEMBLY ( 2 ) TAPPET AND PUSH ROD Visually inspect the tappet camshaft contact surfaces for pitting, cracking, and other abnormal conditions. The tappet must be replaced if any of these conditions are present. Refer to the illustration at the left. 1 Pitting 2 Cracking 3 Normal contact...
Page 65 ENGINE ASSEMBLY ( 2 ) Tappet and Cylinder Body Clearance mm(in) Standard Limit 0.03 (0.0012) 0.1 (0.0039) Push Rod Curvature 1. Lay the push rod on a surface plate. 2. Roll the push rod along the surface plate and mea- sure the push rod curvature with a thickness gauge.
Page 66 ENGINE ASSEMBLY ( 2 ) Cam Height Measure the cam height (H) with a micrometer. If the measured value is less than the specified limit, the camshaft must be replaced. Cam Height H mm(in) Standard Limit 42.08 (1.65) 41.65 (1.64) Camshaft Run-Out 1.
Page 67 ENGINE ASSEMBLY ( 2 ) Camshaft Bearing Installation 1. Align the bearing oil holes with the cylinder body oil holes. 2. Use the camshaft bearing replacer installer to install the camshaft bearing. Bearing Replacer: 5-8840-2038-0 Camshaft End Play 1. Before removing the camshaft gear 1, push the thrust plate 2 as far as it will go toward the cam- shaft gear 3.
Page 68 ENGINE ASSEMBLY ( 2 ) CRANKSHAFT AND BEARING Inspect the surface of the crankshaft journals and crankpins for excessive wear and damage. Inspect the oil seal fitting surfaces for excessive wear and damage. Inspect the oil ports for obstructions. Note: To increase crankshaft strength, tufftriding (Nitrizing Treatment) has been applied.
Page 69 ENGINE ASSEMBLY ( 2 ) Note: The ammonium cuprous chloride solution is highly cor- rosive. Because of this, it is imperative that the surfaces being tested be cleaned immediately after completing the test. Crankshaft Run-Out 1. Set a dial indicator to the center of the crankshaft journal.
Page 70 ENGINE ASSEMBLY ( 2 ) Crankshaft Journal Diameter mm(in) Standard Limit 59.917 – 59.932 59.910 A-4JA1 (2.3589 – 2.3595) (2.3587) 69.917 – 69.932 69.910 A-4JB1 (2.7526 – 2.7531) (2.7524) Crankpin Diameter mm(in) Standard Limit 52.915 – 52.930 (2.0833 – 2.0839) 52.906 (2.0829)
Page 71 ENGINE ASSEMBLY ( 2 ) Crankpin and Bearing Clearance If the clearance between the measured bearing inside diameter and the crankpin exceeds the specified limit, the bearing and/or the crankshaft must be replaced. Crankpin and Bearing Clearance mm(in) Standard Limit 0.029 –...
Page 72 ENGINE ASSEMBLY ( 2 ) 9. Compare the width of the Plastigage attached to either the crankshaft or the bearing against the scale printed on the Plastigage container. If the measured value exceeds the limit, perform the following additional steps. 1) Use a micrometer to measure the crankshaft outside diameter.
Page 73 ENGINE ASSEMBLY ( 2 ) 5. Install the bearing cap and tighten it to the specified torque. Do not allow the connecting rod to move when installing and tightening the bearing cap. Connecting Rod Bearing Cap Bolt Torque kgf·m(lb.ft/N·m) 8.0 – 9.0 (57.9 – 65.1/78.4 – 88.2) 6.
Page 74 ENGINE ASSEMBLY ( 2 ) CRANKSHAFT PILOT BEARING Check the crankshaft pilot bearing for excessive wear and damage and replace it if necessary. Crankshaft Pilot Bearing Replacement Crankshaft Pilot Bearing Removal Use the pilot bearing remover to remove the pilot bear- ing.
Page 75 ENGINE ASSEMBLY ( 2 ) FLYWHEEL AND RING GEAR Flywheel 1. Inspect the flywheel friction surface for excessive wear and heat cracks. 2. Measure the flywheel friction surface wear amount (depth) The flywheel friction surface area actually making contact with the clutch driven plate (the shaded area in the illustration) will be smaller than the original machined surface area.
Page 76 ENGINE ASSEMBLY ( 2 ) Ring Gear Installation 1. Heat the ring gear evenly with a gas burner to invite thermal expansion. Do not allow the temperature of the gas burner to exceed 200°C (390°F). 2. Install the ring gear when it is sufficiently heated. The ring gear must be installed with the chamfer facing the clutch.
Page 77 ENGINE ASSEMBLY ( 2 ) Piston Ring Gap mm(in) Standard Limit 1 s t Compression Ring 0.20 – 0.40 (0.008 – 0.016) 2nd Compression Ring (0.059) 0.10 – 0.30 Oil Ring (0.004 – 0.012) Piston Ring and Piston Ring Groove Clearance Use a feeler gauge to measure the clearance between the piston ring and the piston ring groove at several points around the piston.
Page 78: Piston Pin
ENGINE ASSEMBLY ( 2 ) PISTON PIN Piston Pin Diameter Use a micrometer to measure the piston pin outside diameter at several points. If the measured value is less than the specified limit, the piston pin must be replaced. Piston Pin Diameter mm(in) Standard Limit...
Page 79: Connecting Rod
ENGINE ASSEMBLY ( 2 ) Connecting Rod Bushing Installation 1. Clamp the connecting rod in a vice. 2. Use the connecting rod bushing installer to install the connecting rod bushing. Connecting Rod Bushing Replacer: 3. Use a piston pin hole grinder 1 fitted with a reamer 2 to ream the piston pin hole.
Page 80 ENGINE ASSEMBLY ( 2 ) Connecting Rod Side Face Clearance 1. Install the connecting rod to the crankpin. 2. Use a feeler gauge to measure the clearance between the connecting rod big end side face and the crankpin side face. If the measured value exceeds the specified limit, the connecting rod must be replaced.
Page 81 ENGINE ASSEMBLY ( 2 ) Idler Gear “A” Inside Diameter 1. Use an inside dial indic ator to measure the idler gear Idler Gear Inside Diameter mm(in) Standard Limit 45.0 – 45.03 45.10 (1.7717 – 1.7728) (1.7756) If the clearance between the idler gear shaft outside diameter and the idler gear inside diameter exceeds the limit, the idler gear must be replaced.
Page 82 ENGINE ASSEMBLY ( 2 ) Oil Seal Installation 1. Apply a coat of engine oil to the oil seal lip circum- ference. 2. Use the oil seal installer and the installer grip to insert the oil seal 1 mm (0.039 in) into the front por- tion of the timing gear case.
Page 83 MEMO...
Page 84 ENGINE ASSEMBLY ( 3 ) SECTION 5 ENGINE ASSEMBLY ( 3 ) TABLE OF CONTENTS ITEM PAGE Reassembly ..............82...
Page 85 ENGINE ASSEMBLY ( 3 ) REASSEMBLY SINGLE UNIT ROCKER ARM SHAFT AND ROCKER ARM Reassembly Steps 1. Rocker arm shaft 5. Rocker arm 2. Rocker arm shaft snap ring 6. Rocker arm shaft spring 3. Rocker arm 7. Rocker arm shaft snap ring 4.
Page 86 ENGINE ASSEMBLY ( 3 ) Important Operations 1. Rocker Arm Shaft 1) Position the rocker arm shaft with the large oil hole (Dia. 4 mm (0.157 in)) facing the front of the engine. 2) Install the rocker arm shaft together with the rocker arm, the rocker arm shaft bracket, and the spring.
Page 87 ENGINE ASSEMBLY ( 3 ) CYLINDER HEAD Reassembly Steps 1. Cylinder head 5. Valve spring 2. Valve spring lower washer 6. Valve spring upper seat 3. Valve stem oil seal 7. Split collar 4. Intake and exhaust valve...
Page 88 ENGINE ASSEMBLY ( 3 ) Important Operations 3. Valve Stem Oil Seal 1) Apply a coat engine oil to the oil seal inner face. 2) Use an oil seal installer to install the oil seal to the valve guide. Oil Seal Installer: 5-8840-2033-0 4.
Page 89 ENGINE ASSEMBLY ( 3 ) PISTON AND CONNECTING ROD Reassembly Steps 1. Piston 5. Piston pin snap ring 2. Piston pin snap ring 6. Piston ring 3. Connecting rod 7. Connecting rod bearing 4. Piston pin...
Page 90 3) Install the piston to the connecting rod. The piston head front mark 1 and the con- necting rod “ISUZU” casting mark 2 must be facing the same direction. 4. Piston pin 1) Apply a coat of engine oil to the piston pin and the piston pin hole.
Page 91 ENGINE ASSEMBLY ( 3 ) 6. Piston Ring 1) Use a piston ring replacer to install the three piston rings. Piston Ring Replacer: Install the piston rings in the order shown in the illustration. 1 Oil ring (Coil expander type) 2 2nd compression ring (Taper undercut type) 3 1st compression ring (Barrel face type) Note:...
Page 92 ENGINE ASSEMBLY ( 3 ) CAMSHAFT, CAMSHAFT TIMING GEAR, AND THRUST PLATE Reassembly Steps 1. Camshaft 3. Thrust plate 2. Feather key 4. Camshaft timing gear...
Page 93 ENGINE ASSEMBLY ( 3 ) Important Operations 4. Camshaft Timing Gear 1) Install the thrust plate 1 . 2) Apply engine oil to the bolt threads 2 . 3) Install the camshaft timing gear with the timing mark stamped side facing out. Camshaft Timing Gear Bolt Torque kgf·m(lb.ft/N·m) 10.0 –...
Page 94 ENGINE ASSEMBLY ( 3 ) MEMO...
Page 95 ENGINE ASSEMBLY ( 3 ) REASSEMBLY ★ ★ ★ Repair kit Reassembly Steps – 1 1. Cylinder body 10. Connecting rod cap with lower bearing 2. Tappet 11. Crankcase (If so equipped) 3. Crankshaft upper bearing 12. Oil pump with oil pipe 4.
Page 96 ENGINE ASSEMBLY ( 3 ) ★ ★ ★ ★ ★ ★ ★ Repair kit Reassembly Steps – 2 1. Idler gear shaft 10. Push rod 2. Idler gear “A” 11. Rocker arm shaft and rocker arm 3. Idler gear “B” 12.
Page 97 ENGINE ASSEMBLY ( 3 ) Important Operations (Reassembly Steps-1) 1. Cylinder Body Use compressed air to thoroughly clean the inside and outside surfaces of the cylinder body, the oil holes, and the water jackets. 2. Tappet 1) Apply a coat of engine oil to the tappet 1 and the cylinder body tappet insert holes 2 .
Page 98 ENGINE ASSEMBLY ( 3 ) 5. Crankshaft Thrust Bearing 1) Apply an ample coat of engine oil to the crank- shaft thrust bearings. 2) Install the crankshaft thrust bearings to the crankshaft center journal. The crankshaft thrust bearing oil groove must be facing the sliding face.
Page 99 ENGINE ASSEMBLY ( 3 ) 8. Camshaft with Camshaft Timing Gear and Thrust Plate 1) Apply a coat of engine oil to the camshaft and the camshaft bearings. 2) Install the camshaft to the cylinder body. Take care not to damage the camshaft bearings. 3) Tighten the thrust plate to the specified torque.
Page 100 ENGINE ASSEMBLY ( 3 ) 6) Position the piston head front mark so that it is facing the front of the cylinder body. 7) Use a piston ring compressor to compress the piston rings. Piston Ring Compressor 8) Use a hammer grip to push the piston in until the connecting rod makes contact with the crankpin.
Page 101 ENGINE ASSEMBLY ( 3 ) 12. Oil Pump with Oil Pipe Install the oil pump with the oil pipe and tighten the bolts to the specified torque. Oil Pump Bolt Torque kgf·m(lb.ft/N·m) 1.4 – 2.4 (10.1 – 17.3/13.7 – 23.5) Note: Take care not to damage the O-rings when tightening the oil pipe bolts.
Page 102 ENGINE ASSEMBLY ( 3 ) 15. Flywheel 1) Block the flywheel with a piece of wood to pre- vent it from turning. 2) Apply a coat of engine oil to the threads of the flywheel bolts. 3) Tighten the flywheel bolts in the numerical order shown in the illustration.
Page 103 ENGINE ASSEMBLY ( 3 ) Important Operations (Reassembly Steps-2) 1. Idler Gear Shaft The idler gear shaft oil hole must be facing up. 2. Idler Gear “A” 1) Apply engine oil to the idler gear 1 and the idler gear shaft 2 . 2) Position the idler gear setting marks “X”...
Page 104 ENGINE ASSEMBLY ( 3 ) 5. Timing Case Cover 1) Before installing the timing gear case, apply a 3 mm x 5 mm (0.12 in x 0.20 in) strip of liquid gasket to the portion of the feather key indicated by the arrow in the illustration.
Page 105 ENGINE ASSEMBLY ( 3 ) 9. Cylinder Head 1) Align the cylinder body dowels and the cylinder head dowel holes. Carefully set the cylinder head to the cylinder head gasket. 2) Apply engine oil to the cylinder head fixing bolt threads and setting faces.
Page 106 ENGINE ASSEMBLY ( 3 ) 15. Glow Plug and Glow Plug Connector 1) Tighten the glow plugs to the specified torque. Glow Plug Torque kgf·m(lb.ft/N·m) 2.0 – 2.5 (14.4 – 18.1/19.6 – 24.5) 2) Install the glow plug connectors. 16. Injection Nozzle Holder 1) Install the injection nozzle gasket 1 and the O- ring 2 to the injection nozzle holder 3 .
Page 107 ENGINE ASSEMBLY ( 3 ) 7 6 9 Reassembly Steps – 3 1. Intake manifold 11. Starter 2. Injection pump 12. Exhaust manifold 3. Fuel injection pump with clip 13. Cooling water intake pipe 4. Fuel leak off pipe 14. Cooling water rubber hose 5.
Page 108 ENGINE ASSEMBLY ( 3 ) Important Operations (Reassembly Steps-3) 1. Intake Manifold Install the intake manifold gasket with the end hav- ing the sharp corners facing the front of the engine. 2. Injection Pump 1) Turn the crankshaft slowly clockwise to align the camshaft timing check hole pointer 1 with the camshaft timing gear “O”...
Page 109 ENGINE ASSEMBLY ( 3 ) 3. Fuel Injection Pipe with Clip 1) Temporarily tighten the injection pipe sleeve nut. 2) Set the clip in the prescribed position. Note: Make absolutely sure that the clip is correctly positioned. An improperly positioned clip will result in injection pipe breakage and fuel pulsing noise.
Page 110 ENGINE ASSEMBLY ( 3 ) 15. Alternator and Adjusting Plate Tighten the alternator bolts and the adjusting plate bolts to the specified torque. Alternator Bolt Torque kgf·m(lb.ft/N·m) 3.6 – 4.6 (26.0 – 33.3/35.3 – 45.1) Tighten the adjusting plate bolts to the specified torque after cooling drive belt installation.
Page 111 MEMO...
Page 112 LUBRICATING SYSTEM SECTION 6 LUBRICATING SYSTEM TABLE OF CONTENTS ITEM PAGE Main data and specifications ........... . . 110 General description .
Page 113 LUBRICATING SYSTEM MAIN DATA AND SPECIFICATIONS Item A-4JA1·A-4JB1 Oil pump type Trochoid Delivery volume Lit(qts)/min. 17.5 (18.4) Pump speed 1000 Delivery pressure kgf/cm (psi/kPa) 4.0 (56.89/392.0) Oil temperature °C(°F) 47 – 53 (116.6 – 127.4) Engine oil SAE 30 Oil filter type...
Page 114 LUBRICATING SYSTEM GENERAL DESCRIPTION LUBRICATING OIL FLOW Battery Warning Light Oil pressure switch Cylinder block oil gallery Idle gear Oil filter and cooler assembly. shaft Filter cartridge Vacuum Camshaft Crank shaft Partial flow pump bearing bearing Main flow oil filter Oil pipe oil filter (If so equipped)
Page 115 LUBRICATING SYSTEM OIL PUMP A-4J Series engine are equipped with a trochoid type oil pump. The oil filter and the water cooled oil cooler are a single unit to increase the cooling effect.
Page 116 LUBRICATING SYSTEM MAIN OIL FILTER OIL FILTER WITH BUILT-IN OIL COOLER...
Page 117: Oil Pump
LUBRICATING SYSTEM OIL PUMP DISASSEMBLY 051ET001 Disassembly Steps 4. Vane 1. Oil pipe 5. Pump body with rotor and pinion 2. Strainer case 3. Pump cover...
Page 118 LUBRICATING SYSTEM INSPECTION AND REPAIR Make the necessary adjustments, repairs, and part replacements if excessive wear or damage is dis- covered during inspection. Vane, Rotor, and Cover Clearance Use a feeler gauge to measure the clearance between the vane, the rotor, and the cover. If the clearance between the vane, the rotor, and the cover exceeds the specified limit, the rotor set (pin, shaft, rotor, and vane) must be replaced.
Page 119 LUBRICATING SYSTEM REASSEMBLY 051ET002 Reassembly Steps 4. Strainer case 1. Pump body with rotor and pinion 5. Oil pipe 2. Vane 3. Pump cover...
Page 120 LUBRICATING SYSTEM OIL FILTER WITH BUILT-IN OIL COOLER DISASSEMBLY Disassembly Steps 1. Drain plug 5. Safety valve 2. Cartridge oil filter 6. Relief valve 3. Oil cooler 7. Oil filter body 4. O-ring...
Page 121 LUBRICATING SYSTEM INSPECTION AND REPAIR Make the necessary adjustments, repairs, and part replacements if excessive wear or damage is discovered during inspection. Relief Valve 1. Attach an oil pressure gauge to the oil gallery near the oil filter. 2. Start the engine to check the relief valve opening pressure.
Page 122 LUBRICATING SYSTEM REASSEMBLY Reassembly Steps 1. Oil filter body 5. Oil cooler 2. Relief valve 6. Oil filter cartridge 3. Safety valve 7. Drain plug 4. O-ring...
Page 123 LUBRICATING SYSTEM Important Operations 2. Relief Vale Tighten the relief valve to the specified torque. Relief Valve Torque kgf·m(lb.ft/N·m) 2.5 – 3.5 (18.1 – 25.3/24.5 – 34.3) 5. Oil Cooler 1) Align the oil filter holes with the body knock pins at installation.
Page 124: Section 7. Cooling System
COOLING SYSTEM SECTION 7 COOLING SYSTEM TABLE OF CONTENTS ITEM PAGE Main data and specifications ........... . . 122 General description .
Page 125 COOLING SYSTEM MAIN DATA AND SPECIFICATIONS Item Water pump type Centrifugal impeller Pump to crankshaft speed ratio (To 1) Delivery volume Lit(qts)/min. 100 (105.5) Pump speed at 3000 rpm Water temperature at 30°C (86°F) Pump bearing type Double row shaft Thermostat type Wax pellet with jiggle valve Valve initial opening temperature...
Page 126 COOLING SYSTEM GENERAL DESCRIPTION COOLANT FLOW The engine cooling system consists of the radiator, the water pump, the cooling fan, and the thermostat. To quickly increase cold engine coolant temperature for smooth engine operation, the coolant is circulated by the water pump and thermostat through the by-pass hose and back to the cylinder body. The coolant does not circulate through the radiator.
Page 127: Water Pump
COOLING SYSTEM WATER PUMP THERMOSTAT A centrifugal type water pump forcefully circulates the coolant through the cooling system. A wax pellet type thermostat is used. The jiggle valve accelerates engine warm-up.
Page 128 COOLING SYSTEM WATER PUMP DISASSEMBLY ★ ★ ★ ★ ★ Disassembly Steps 1. O-ring 5. Bearing unit 6. Thrower 2. Set screw 3. Cooling fan center 7. Water pump body 4. Impeller and seal unit...
Page 129 COOLING SYSTEM Important Operations 3. Cooling Fan Center Remove the fan center with a bench press and a bar. 4. Impeller and Seal Unit Remove the impeller and seal unit with a bench press and bar. Note: Do not drive out the impeller with a hammer. Damage to the impeller will result.
Page 130 COOLING SYSTEM INSPECTION AND REPAIR Make the necessary adjustments, repairs, and part replacements if excessive wear or damage is discovered during inspection. Bearing Unit Check the bearing for abnormal noise, biding, and other abnormal conditions.
Page 131 COOLING SYSTEM REASSEMBLY ★ ★ ★ ★ ★ Reassembly Steps 5. Impeller and seal unit 1. Water pump body 2. Thrower 6. Cooling fan center 3. Bearing unit 7. O-ring 4. Set screw...
Page 132 COOLING SYSTEM Important Operations Bearing Unit Set Screw Align the bearing set screw hole with the pump body set screw hole. Press the bearing unit into place. Secure the bearing with the set screw. Impeller and Seal Unit Apply a thin coat of liquid gasket to the seal unit outer periphery.
Page 133 COOLING SYSTEM Note: 1. The fan center and the impeller are installed to the water pump shaft with a press. Never attempt to remove and reinstall the fan center and the impeller a second time. Replace the entire water pump assembly. Removing and reinstalling the fan center and the impeller a second time may result in the breakdown of the water pump during engine operation and...
Page 134 COOLING SYSTEM THERMOSTAT INSPECTION AND REPAIR Make the necessary adjustments, repairs, and part replacements if excessive wear or damage is discovered during inspection. Operating Test 1. Completely submerge the thermostat in water. 2. Heat the water. Stir the water constantly to avoid direct heat being applied to the thermostat.
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Page 136: Section 8. Fuel System
FUEL SYSTEM SECTION 8 FUEL SYSTEM TABLE OF CONTENTS ITEM PAGE Main data and specifications ........... . . 134 General description .
Page 137 FUEL SYSTEM MAIN DATA AND SPECIFICATIONS Item Injection pump type Bosch A type Plunger outside diameter mm(in.) 9.0 (0.35) Plunger lift mm(in.) 3.25 – 3.35 (0.128 – 0.132) Governor type RSV variable speed mechanical type Fuel feed pump type Single action Injection nozzle type Hole type Number of injection nozzle orifices...
Page 138 FUEL SYSTEM GENERAL DESCRIPTION COOLANT FLOW Fuel Nozzle filter Water separator Injection pump Fuel tank The fuel system consists of the fuel tank, the water separator (if so equipped), the fuel filter, the injection pump, and the injection nozzle. The fuel from the fuel tank passes through the water separator and the fuel filter where water particles and other foreign material are removed from the fuel.
Page 139: Injection Nozzle
FUEL SYSTEM INJECTION NOZZLE Nozzle holder Adjusting shim Spring Spring seat Injection nozzle Retaing nut A hole (with 4 orifices) type injection nozzle is used. It consists of the nozzle body and the needle valve assembly. The injection nozzle sprays pressurized fuel from the injection pump into the combustion chamber through the nozzle body injection orifice.
Page 140 FUEL SYSTEM FUEL FILTER AND WATER SEPARATOR Drain Level A cartridge type fuel filter and a water separator are used. As the inside of the injection pump is lubricated by the fuel which it is pumping, the fuel must be perfectly clean.
Page 141 FUEL SYSTEM INJECTION NOZZLE DISASSEMBLY Disassembly Steps 5. Spring 1. Retaining nut 2. Injection nozzle 6. Adjusting shim 3. Spacer 7. Nozzle holder 4. Spring seat...
Page 142 FUEL SYSTEM Important Operations Performance this test before disassembling the injection nozzle. 1) Install the injection nozzle to the nozzle tester. 2) Use the nozzle tester to apply compressed fuel at 185 kgf/cm (2,630 psi/18.1 MPa) to the injection nozzle. 3) Check the area around the nozzle seat for fuel leakage.
Page 143 FUEL SYSTEM INSPECTION AND REPAIR Make the necessary adjustments, repairs, and part replacements if excessive wear or damage is discovered during inspection. Injection Nozzle Needle Inspection Remove the nozzle needle from the nozzle body. Carefully wash the nozzle needle and the nozzle body in clean diesel fuel.
Page 144 FUEL SYSTEM REASSEMBLY Reassembly Steps 1. Nozzle holder 5. Spacer 2. Adjusting shim 6. Injection nozzle 7. Retaining nut 3. Spring 4. Spring seat...
Page 145 FUEL SYSTEM Important Operations Adjust Shim Adjust Shim Availability mm(in.) Range 0.50-0.50 (0.02-0.06) Increment 0.025 (0.001) Total No. of Shims Retaining Nut Tighten to the retaining nut to the specified torque. Retaining Nut Torque kgf·m(lbs.ft./N·m) 4.0 – 5.0 (28.9 – 36.2/39.2 – 49.0) Injection Nozzle Adjustment 1.
Page 146 FUEL SYSTEM INJECTION PUMP DATA INJECTION PUMP IDENTIFICATION Refer to the Item “INJECTION PUMP IDENTIFICATION” on Page 1– of the “SERVICING” Section of this Workshop Manual. INJECTION VOLUME ADJUSTMENT TEST CONDITIONS Injection Nozzle ZEXEL No.: 105780-0000 Bosch Type No.: DN12SD12T Injection Nozzle Holder ZEXEL No.: 105780-2080 Bosch Type No.: EF8511/9...
Page 147: Governor Adjustment
FUEL SYSTEM INJECTION QUANTITY Injection Maximum Adjusting Rod Position Pump Speed Quantity Variation Fixed Remarks Point (mm) (rpm) (cc/1000 Strokes) 1,500 64 – 65 ± 2.5 Lever Basic Adjust max. var. bet. cyl. at R = 6.6. About 6.6 9.5 – 13.5 ±...
Page 148 FUEL SYSTEM Speed Lever Angle ±3° ±5° 35° 12° Stop ±5° 25°...
Page 149 MEMO...
Page 150: Section 9. Engine Electricals
ENGINE ELECTRICALS SECTION 9 ENGINE ELECTRICALS TABLE OF CONTENTS ITEM PAGE Starter ............... . 148 Alternator .
Page 151: Starter Identification
Hitachi starter are identified by name plate attached to the yoke. (Illustration) H I T A C H I MADE IN JAPAN 1 Isuzu part number 2 Manufacturer‘s code number 3 Rated voltage 4 Manufacturer‘s production mark H I T A C H I...
Page 152 ENGINE ELECTRICALS MAIN DATA AND SPECIFICATION Isuzu Part No. 8-97084-877-0 8-94423-452-0 Hitachi code No. S13-11 S24-07 Rated voltage Rated output Rating Direction of rotation (Viewed from the pinion side) Clockwise Clutch type Roller Terminal voltage (No. Load) Minimum current (No. Load) Starter motor minimum operating speed (No.
Page 153 ENGINE ELECTRICALS GENERAL DESCRIPTION This starter is equipped with a reduction gear between the armature shaft and the flywheel ring gear drive pinion. This construction enable the starter to reduce 27% of the armature shaft revolution speed at the pinion contributing to achieve more compact size and higher cold engine starting ability than the non-reduction gear type starter.
Page 154 ENGINE ELECTRICALS DISASSEMBLY Disassembly Steps 1. Lead wire 11. Armature 2. Bolt 12. Screw 3. Magnetic switch 13. Bearing retainer 4. Torsion spring 14. Snap ring 5. Plunger 15. Pinion stopper 6. Shim 16. Return spring 7. Through bolt 17. Pinion shaft 8.
Page 155 ENGINE ELECTRICALS Important Operations 1. Lead Wire Disconnect lead wire at the magnetic switch. 3. Magnetic Switch Remove the magnetic switch fixing bolts, then remove the switch from the shift lever. 4. Torsion Spring 5. Plunger 6. Shim Remove the torsion spring, plunger and shim from the magnetic switch.
Page 156 ENGINE ELECTRICALS 9. Brush Holder Using long-nose pliers remove the 4 brushes. 13. Bearing retainer Remove the bearing retainer, then remove the pin- ion from the gear case. 14. Snap Ring Remove the snap ring using a screw driver or equivalent, then disassemble the pinion assembly.
Page 157 ENGINE ELECTRICALS INSPECTION AND REPAIR Make the necessary adjustments, repairs, and part replacements if excessive wear or damage is dis- covered during inspection. ARMATURE Armature Short Circuit Test 1. Place the armature on a growler tester 1. 2. Hold a hack saw blade 2 against the armature core while slowly rotating the armature.
Page 158 ENGINE ELECTRICALS Commutator Run-Out Test Use a dial indicator and a V-block to measure the com- mutator runout. If the measure value exceeds the limit, the commutator must be replaced. Commutator Run-Out mm(in.) Standard Limit 0.02 (0.0008) 0.05 (0.002) Commutator Outside Diameter Measurement Use a vernier caliper to measure the commutator out- side diameter.
Page 159 ENGINE ELECTRICALS YOKE Field Winding Ground Test Use a circuit tester to check the field winding ground. 1. Touch one probe to the brush field winding end. 2. Touch the other probe to the bare surface of the yoke body. There should be no continuity.
Page 160 ENGINE ELECTRICALS Brush Spring Inspection Visually check the brush spring for weakness and rust- ing. Replace the brush spring if it is weak or rusted. Use a spring balancer to measure the spring tension. If the measured valve exceeds the limit, the brush spring must be replaced.
Page 161 ENGINE ELECTRICALS Check for continuity across magnetic switch “S” termi- nal and “M” terminal. If no continuity exists, series coil are open and should be replaced.
Page 162 ENGINE ELECTRICALS REASSEMBLY Reassembly Steps 1. Magnetic switch 11. Pinion stopper 2. Shim 12. Snap ring 3. Plunger 13. Bearing retainer 4. Torsion spring 14. Bolt 5. Shift lever 15. Armature 6. Dust cover 16. Yoke 7. Bolt 17. Brush holder 8.
Page 163 ENGINE ELECTRICALS Important Operations 4. Torsion Spring 5. Shift Lever Set the torsion spring to the hole in magnetic switch. Insert the shift lever, via the torsion spring, into plunger hole in the magnetic switch. 6. Dust Cover Install the magnetic switch in gear case. Make sure to install the dust cover.
Page 164 ENGINE ELECTRICALS 19. Through Bolt Tighten the through bolts to the specified torque a little at a time. Through Bolt Torque kgf·m(lb.ft./N·m) 0.5 – 0.7 (3.6 – 5.1/4.9 – 6.9) 20. Lead Wire Tighten the lead wire to the specified torque. Lead Wire Torque kgf·m(lb.ft./N·m) 0.8 –...
Page 165 ENGINE ELECTRICALS ALTERNATOR ALTERNATOR IDENTIFICATION Hitachi alternators are identified by name plate attached to the rear cover. (Illustration) 1 Isuzu part number 2 Manufacturer‘s code number 3 Rated output IC REG BUILT IN Hitachi. Ltd. Japan 4 Manufacturer‘s production mark...
Page 166 ENGINE ELECTRICALS MAIN DATA AND SPECIFICATION Engine Model to be Equipped A – 4J Series Manufacturer‘s name HITACHI Isuzu Part No. 8-94423-756-0 8-94431-560-0 5-81200-335-0 Manufacturer‘s Code No. LR135-127 LR215-50 LR200-24 Rated voltage Rated output Operating speed 1000–13500 1000–5000 1000–13500 Rated output at rpm A/V/rpm 33-37/13.5/5000...
Page 167 ENGINE ELECTRICALS GENERAL DESCRIPTION The alternator consists of the front cover, the rotor, the stator, the built-in IC regulator (some engines use a Tirrell alternator with separate regulator), and the rear cover. This small size and light weight alternator provides excellent reliability. Its simple construction makes it very easy to service.
Page 168 ENGINE ELECTRICALS DISASSEMBLY These disassembly steps are based on the built-in IC regulator type. Disassembly Steps 1. Through bolt 7. Ball bearing 2. Rear cover and stator 8. Front cover 3. Pulley and fan 9. Stator 4. Spacer collar 10. Rectifier with brush holder 5.
Page 169 ENGINE ELECTRICALS Important Operations 3. Pulley and Fan (1) Clamp the rotor shaft in a soft jaw vise. (2) Loosen the pulley lock nut 1. (3) Remove the pulley 2 along with the spacer collar. 4. Rotor and Bearing (1) Use a plastic hammer or a press 1 to remove the rotor from the front cover 2.
Page 170 ENGINE ELECTRICALS INSPECTION AND REPAIR Make the necessary adjustments, repairs, and part replacements if excessive wear or damage is dis- covered during inspection. ROTOR AND BEARING Check the face of the slip rings for contamination and roughness. If found to be roughened, dress with a fine sand paper (#500 –...
Page 171 ENGINE ELECTRICALS Rotor Coil Continuity Test Use an circuit tester to test the rotor coil continuity. 1. Touch both circuit tester probes to the rotor coil slip rings. 2. Note the circuit tester reading. The circuit tester should register approximately 9 ohms.
Page 172 ENGINE ELECTRICALS 4. Note the circuit tester reading. If the two readings (Steps 2 and 4) are identical, the stator coil has continuity. If the two circuit tester readings are different, there is no stator continuity. 5. Check the neutral junction (arrow mark) for breaks. If breaks are found, repair and repeat the stator coil continuity test.
Page 173 ENGINE ELECTRICALS 3. Note the meter reading for each diode terminal. All of the diode should show continuity. If a diode shows no continuity, it is open circuit. The rectifier assembly must be replaced. 4. Touch the circuit tester negative probe to the recti- fier holder.
Page 174 ENGINE ELECTRICALS Note: 1. The stator lead wires must be cut to the proper length before they are connected to the rectifier lead wires. If the stator lead wires are too long or too short, trouble may occur. Stator Lead Wire Length mm(in.) 33.5 (1.32) 2.
Page 175 ENGINE ELECTRICALS REASSEMBLY Reassembly Steps 1. Rear cover 7. Ball bearing 2. IC regulator 8. Bearing retainer 3. Rectifier with brush holder 9. Rotor with bearing 4. Stator 10. Spacer collar 5. Rear cover and stator 11. Pulley and fan 6.
Page 176 ENGINE ELECTRICALS Important Operations 3. Rectifier with Brush Holder 4. Stator When connecting stator coil leads and diode leads using solder, use long-nose pliers and finish the work as quickly as possible to prevent the heat from being transferred to the diodes. 11.
Page 177 MEMO...
Page 178: Section 10. Troubleshooting
TROUBLESHOOTING SECTION 10 TROUBLESHOOTING TABLE OF CONTENTS ITEM PAGE Hard starting ..............177 Unstable idling .
Page 179 TROUBLESHOOTING TROUBLESHOOTING Refer to this Section to quickly diagnose and repair engine problems. Each troubleshooting chart has three headings arranged from left to right. Checkpoint Trouble Cause Countermeasure This Section is divided into ten sub-sections: Hard Starting 1) Starter inoperative 2) Starter operates but engine does not turn over 3) Engine turns over but does not start Unstable Idling...
Page 180: Hard Starting
TROUBLESHOOTING HARD STARTING STARTER INOPERATIVE Checkpoint Trouble Cause Countermeasure Neutral switch (If so equipped) Defective neutral switch Replace the neutral switch Loose battery cable terminals Clean and/or retighten the bat- Battery Poor connections due to rusting tery cable terminals Battery discharged or weak Recharge or replace the battery Fan belt loose or broken Adjust or replace the fan belt...
Page 181 TROUBLESHOOTING HARD STARTING STARTER OPERATES BUT ENGINE DOES NOT TURN OVER Checkpoint Trouble Cause Countermeasure Loose battery cable terminals Clean and/or retighten the bat- Battery Poor connections due to rusting tery cable terminals Battery discharged or weak Recharge or replace the battery Fan belt loose or broken Adjust or replace the fan belt Starter...
Page 182: Engine Turns Over But Does Not Start
TROUBLESHOOTING HARD STARTING ENGINE TURNS OVER BUT DOES NOT START Checkpoint Trouble Cause Countermeasure Defective engine stop mechanism Replace the engine stop Engine stop mechanism control wire improperly adjusted mechanism (In line pump) Adjust the control wire Defective fuel cut solenoid valve Replace the fuel cut solenoid (VE pump) valve...
Page 183 TROUBLESHOOTING HARD STARTING ENGINE TURNS OVER BUT DOES NOT START FUEL IS BEING DELIVERED TO THE INJECTION PUMP Checkpoint Trouble Cause Countermeasure Continued from the previous page Injection nozzle injection starting Adjust or replace the injection Injection nozzle pressure too low nozzle Improper spray condition Defective fuel injection nozzle...
Page 184: Unstable Idling
TROUBLESHOOTING UNSTABLE IDLING Checkpoint Trouble Cause Countermeasure Idling system Idling improperly adjusted Adjust the idling Defective fast idling speed Repair or replace the fast idling Fast idling speed control device control device speed control device Accelerator control system Adjust the accelerator control Accelerator control system improperly adjusted system...
Page 185 TROUBLESHOOTING UNSTABLE IDLING Checkpoint Trouble Cause Countermeasure Continued from the previous page Repair or replace the governor Injection pump Defective governor lever operation lever Regulator valve improperly Adjust or replace the regulator adjusted (VE pump only) valve Broken plunger spring Replace the plunger spring Worn plunger Replace the plunger assembly...
Page 186: Unstable Idling
TROUBLESHOOTING UNSTABLE IDLING Checkpoint Trouble Cause Countermeasure Continued from the previous page Valve clearance improperly Valve clearance Adjust the valve clearance adjusted Blown out cylinder head gasket Worn cylinder liner Compression pressure Piston ring sticking or broken Replace the related parts Improper seating between the valve and the valve seat...
Page 187: Insufficient Power
TROUBLESHOOTING INSUFFICIENT POWER Checkpoint Trouble Cause Countermeasure Clean or replace the air cleaner Air cleaner Clogged air cleaner element element Fuel Water particles in the fuel Replace the fuel Replace the fuel filter element or Fuel filter Clogged fuel filter element the fuel filter cartridge Repair or replace the fuel feed Fuel feed pump...
Page 188 TROUBLESHOOTING INSUFFICIENT POWER Checkpoint Trouble Cause Countermeasure Continued from the previous page Defective regulating valve Repair or replace the regulating Injection pump (VE pump only) valve Defective delivery valve Replace the delivery valve Defective timer Repair or replace the timer Worn cam disc (VE pump only) Replace the cam disc Adjust or replace the control...
Page 189 TROUBLESHOOTING INSUFFICIENT POWER Checkpoint Trouble Cause Countermeasure Continued from the previous page Injection pump Worn plunger Replace the plunger assembly Worn camshaft (In-line pump only) Replace the camshaft Worn roller tappet (In-line pump Replace the roller tappet only) Worn cam disc (VE pump only) Replace the cam disc Booster compensator pipe Replace the booster compen-...
Page 190 TROUBLESHOOTING INSUFFICIENT POWER Checkpoint Trouble Cause Countermeasure Continued from the previous page Turbocharger Defective turbocharger assembly Replace the turbocharger assembly Blown out cylinder head gasket Worn cylinder liner Compression pressure Piston ring sticking or broken Replace the related parts Improper seating between the valve and the valve seat Valve clearance improperly Valve clearance...
Page 191: Excessive Fuel Consumption
TROUBLESHOOTING EXCESSIVE FUEL CONSUMPTION Checkpoint Trouble Cause Countermeasure Repair or replace the fuel system Fuel system Fuel leakage related parts Clean or replace the air cleaner Air cleaner Clogged air cleaner element element Idling speed Poorly adjusted idling speed Adjust the idling speed Injection nozzle injection starting Adjust or replace the injection Injection nozzle...
Page 192 TROUBLESHOOTING EXCESSIVE FUEL CONSUMPTION Checkpoint Trouble Cause Countermeasure Continued from the previous page Turbocharger Defective turbocharger assembly Replace the turbocharger assembly Valve clearance improperly Valve clearance Adjust the valve clearance adjusted Blown out cylinder head gasket Worn cylinder liner Compression pressure Piston ring sticking or broken Replace the related parts Improper seating between the...
Page 193: Excessive Oil Consumption
TROUBLESHOOTING EXCESSIVE OIL CONSUMPTION Checkpoint Trouble Cause Countermeasure Engine oil unsuitable Replace the engine oil Engine oil Too much engine oil Correct the engine oil volume Oil leakage from the oil seal Replace the oil seal and/or the Oil seal and gasket and/or the gasket gasket Air breather...
Page 194 TROUBLESHOOTING OVERHEATING Checkpoint Trouble Cause Countermeasure Cooling water Insufficient cooling water Replenish the cooling water Fan coupling (if so equipped) Oil leakage from the fan coupling Replace the fan coupling Fan belt loose or cracked causing Fan belt Replace the fan belt slippage Defective radiator cap or clogged Replace the radiator cap or clean...
Page 195 TROUBLESHOOTING OVERHEATING Checkpoint Trouble Cause Countermeasure Continued from the previous page Cooling system clogged by Clean the foreign material from Cooling system foreign material the cooling system Fuel injection timing improperly Fuel injection timing Adjust the fuel injection timing adjusted...
Page 196: White Exhaust Smoke
TROUBLESHOOTING WHITE EXHAUST SMOKE Checkpoint Trouble Cause Countermeasure Fuel Water particles in the fuel Replace the fuel Fuel injection timing Delayed fuel injection timing Adjust the fuel injection timing Blown out cylinder head gasket Worn cylinder liner Compression pressure Piston ring sticking or broken Replace the related parts Improper seating between the valve and the valve seat...
Page 197: Dark Exhaust Smoke
TROUBLESHOOTING DARK EXHAUST SMOKE Checkpoint Trouble Cause Countermeasure Clean or replace the air cleaner Air cleaner Clogged air cleaner element element Injection nozzle injection starting Adjust or replace the injection Injection nozzle pressure too low nozzle Improper spray condition Fuel injection timing improperly Fuel injection timing Adjust the fuel injection timing adjusted...
Page 198: Oil Pressure Does Not Rise
TROUBLESHOOTING OIL PRESSURE DOES NOT RISE Checkpoint Trouble Cause Countermeasure Improper viscosity engine oil Replace the engine oil Engine oil Too much engine oil Correct the engine oil volume Defective oil pressure gauge or Repair or replace the oil pres- Oil pressure gauge or unit unit sure gauge or unit...
Page 199 TROUBLESHOOTING OIL PRESSURE DOES NOT RISE Checkpoint Trouble Cause Countermeasure Continued from the previous page Worn camshaft and camshaft Replace the camshaft and the Camshaft bearing camshaft bearings Replace the crankshaft and/or Crankshaft and bearings Worn crankshaft and bearings the bearings...
Page 200: Abnormal Engine Noise
TROUBLESHOOTING ABNORMAL ENGINE NOISE Engine Knocking Checkpoint Trouble Cause Countermeasure Check to see that the engine has been thoroughly warmed up before beginning the troubleshooting procedure. Fuel Fuel unsuitable Replace the fuel Fuel injection timing improperly Fuel injection timing Adjust the fuel injection timing adjusted Improper injection nozzle starting Adjust or replace the injection...
Page 201 TROUBLESHOOTING ABNORMAL ENGINE NOISE Gas Leakage Noise Checkpoint Trouble Cause Countermeasure Continued from the previous page Loosely connected exhaust mani- Tighten the exhaust manifold Exhaust manifold fold and/or glow plugs connections Cylinder head gasket Damaged cylinder head gasket Replace the cylinder head gasket Continuous Noise Fan belt Loose fan belt...
Page 202 TROUBLESHOOTING ABNORMAL ENGINE NOISE Slapping Noise Checkpoint Trouble Cause Countermeasure Valve clearance improperly Valve clearance Adjust the valve clearance adjusted Rocker arm Damaged rocker arm Replace the rocker arm Flywheel Loose flywheel bolts Retighten the flywheel bolts Worn or damaged crankshaft Replace the crankshaft and/or the Crankshaft and thrust bearings and/or thrust bearings...
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Page 204: Section 11. Special Tool List
SPECIAL TOOL LIST SECTION 11 SPECIAL TOOL LIST...
Page 205: Special Tool List
SPECIAL TOOL LIST SPECIAL TOOL LIST ITEM NO. ILLUSTRATION PART NO. PARTS NAME PAGE 5-8840-0145-0 Measuring Device 5-8840-2675-0 Compression Gauge 5-8840-9029-0 Compression Gauge Adapter 5-8840-0019-0 Sliding Hammer Nozzle Holder 5-8840-2034-0 Remover Oil Seal Remover 5-8840-2363-0 (Axial Type) 9-8523-1423-0 Valve Spring Compressor Camshaft Timing Gear 5-8840-0086-0 Universal Puller...
Page 206 SPECIAL TOOL LIST ITEM NO. ILLUSTRATION PART NO. PARTS NAME PAGE 5-8840-2040-0 Cylinder Liner Installer 5-8840-2038-0 Camshaft Bearing Replacer Crankshaft Timing Gear 9-8840-2057-0 Remover Crankshaft Timing Gear 9-8522-0020-0 Installer Crankshaft Pilot Bearing 5-8840-2000-0 Remover Crankshaft Pilot Bearing 5-8522-0024-0 Installer Crankshaft Front Oil Seal 5-8840-2061-0 Installer Valve Stem Oil Seal...
Page 207 MEMO...
Page 208: Section 12. Repair Standards
Repair standards chart ..................206 General Rules These tables provide standards relating the repair of the following diesel engine; Model A-4JA1, A-4JB1 These Repair Standards are based on inspection items, together with dimensions, assembly standards, limit values, and repair procedures.
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Page 222: Section 13. Conversion Table
CONVERSION TABLE SECTION 13 CONVERSION TABLES INDEX CONTENTS PAGE Length ............... . 220 Area .
Page 223 CONVERSION TABLE LENGTH FEET TO METERS ––– –––0 0.305 0.610 0.914 1.219 1.524 1.829 2.134 2.438 2.743 ––– 3.048 3.353 3.658 3.962 4.267 4.572 4.877 5.182 5.486 5.791 6.096 6.401 6.706 7.010 7.315 7.620 7.925 8.230 8.534 8.839 9.144 9.449 9.754 10.058 10.363...
Page 224 CONVERSION TABLE AREA SQUARE INCHES TO SQUARE CENTIMETERS ––– –––00 6.452 12.903 19.355 25.806 32.258 38.710 45.161 51.613 58.064 ––– 64.516 70.968 77.419 83.871 90.322 96.774 103.226 109.677 116.129 122.580 129.032 135.484 141.935 148.387 154.838 161.290 167.742 174.193 180.645 187.096 193.548 200.000 206.451...
Page 225 CONVERSION TABLE VOLUME GALLONS (U.S.) TO LITERS U.S. gal. U.S.gal. liters liters liters liters liters liters liters liters liters liters ––– –––00 3.7854 7.5709 11.3563 15.1417 18.9271 22.7126 26.4980 30.2834 34.0688 ––– 37.8543 41.6397 45.4251 49.2105 52.9960 56.7814 60.5668 64.3523 68.1377 71.9231 75.7085...
Page 226 CONVERSION TABLE MASS POUNDS TO KILOGRAMS lbs. lbs. ––– –––0 0.454 0.907 1.361 1.814 2.268 2.722 3.175 3.629 4.082 ––– 4.536 4.990 5.443 5.897 6.350 6.804 7.257 7.711 8.165 8.618 9.072 9.525 9.979 10.433 10.886 11.340 11.793 12.247 12.701 13.154 13.608 14.061 14.515...
Page 227 CONVERSION TABLE PRESSURE POUNDS PER SQUARE INCHES TO KILOGRAMS PER SQUARE CENTIMETERS lb/in lb/in (psi) kgf/cm kgf/cm kgf/cm kgf/cm kgf/cm kgf/cm kgf/cm kgf/cm kgf/cm kgf/cm (psi) ––– –––0 0.0703 0.1406 0.2109 0.2812 0.3515 0.4218 0.4921 0.5625 0.6328 ––– 0.7031 0.7734 0.8437 0.9140 0.9843...
Page 228 CONVERSION TABLE TORQUE FOOT POUNDS TO KILOGRAMMETERS ft. lbs. ft lbs. kgf-m kgf-m kgf-m kgf-m kgf-m kgf-m kgf-m kgf-m kgf-m kgf-m ––– –––0 0.138 0.277 0.415 0.553 0.691 0.830 0.968 1.106 1.244 ––– 1.383 1.521 1.659 1.797 1.936 2.074 2.212 2.350 2.489 2.627...
Page 229 CONVERSION TABLE TEMPERATURE FAHRENHEIT TO CENTIGRADE °F °C °F °C °F °C °F °C °F °C °F °C °F °C °F °C -51.1 -18.9 13.3 45.6 77.8 110.0 142.2 174.4 -50.0 -17.8 14.4 46.7 78.9 111.1 143.3 175.6 -48.9 -16.7 15.6 47.8 80.0...
Page 230 Copyright reserved for this manual may not be reproduced or copied, in whole or in part, without the written consent of ISUZU MOTORS LIMITED. WORKSHOP MANUAL (INDUSTRIAL) A-4JA1, A-4JB1 (IDE-2310) Issued by ISUZU MOTORS LIMITED POWERTRAIN SERVICE & PARTS POWERTRAIN OPERATIONS...
Page 231 IDE-2310 PRINTED IN JAPAN...

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