This is the Isuzu 4JG2 Service Manual (publication 604-01-200K), a 219-page factory guide to the 4JG2 industrial diesel engine. It runs from general information and specifications through maintenance, three engine assembly sections covering disassembly, inspection and repair, and reassembly, and on to the individual system chapters.
Separate sections cover the lubricating system, cooling system, fuel system and engine electricals, backed by a full troubleshooting chapter and a special tool list. You get the working numbers, including cold valve clearance of 0.40 mm, fuel injection timing at 6 degrees BTDC, low idle of 675 to 725 rpm and the main torque figures for the flywheel, connecting rods and cylinder head.
For owners and mechanics servicing a 4JG2 in a forklift, genset or light truck, this PDF supplies the exact procedures and settings needed to maintain, diagnose and rebuild the engine.
What's Inside This Manual
| System | Pages | Key Topics |
|---|---|---|
| General Information | 4-21 | General Repair Instructions, Main Data and Specifications, Tightening Torque Specifications, Angular Nut and Bolt Tightening Method, Special Parts Fixing Nuts and Bolts |
| Maintenance | 22-33 | Model Identification, Injection Pump Identification, Lubricating System, Fuel System, Cooling System, Valve Clearance Adjustment |
| Engine Assembly(1) | 34-51 | |
| Engine Assembly(2) | 52-87 | |
| Engine Assembly(3) | 88-115 | |
| Lubricating System | 116-127 | Main Data and Specifications, General Description, Oil Pump, Oil Filter with Built-In Oil Cooler |
| Cooling System | 128-137 | Main Data and Specifications, General Description, Water Pump, Thermostat |
| Fuel System | 138-149 | General Description, Injection Nozzle, Injection Pump Data |
| Engine Electricals | 150-175 | Starter, Alternator |
| Troubleshooting | 176-201 | Hard Starting, Unstable Idling, Insufficient Power, Excessive Fuel Consumption, Excessive Oil Consumption, Overheating |
| Special Tool List | 202-205 | Compression Gauge, Compression Gauge Adaptor, Valve Spring Compressor, Valve Guide Replacer, Cylinder Liner Installer, Camshaft Bearing Replacer |
| Conversion Table | 206-219 | Length, Area, Volume, Mass, Pressure, Torque |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Level Sensor Torque | 1.3 (9/13) kg-m (lb.ft/N-m) | p. 21 |
| Oil Filter Bolt Torque | 1.4 - 2.4 (10 - 17/14 - 24) kg-m(lb.ft/N-m) | p. 112 |
| Starter Bolt Torque | 6.7 - 8.7 (48 - 63/60 - 85) kg-m(lb.ft/N-m) | p. 111 |
| Thermostat Initial Opening Temperature | 76.5 (170) °C(°F) | p. 24 |
| Injection pressure | 150 (2130/14.7) kg/cm² (psi/MPa) | p. 23 |
| Cylinder Head Bolt Torque (1st stop) | 4.5 - 5.5 (33 - 40/44 - 54) kg-m(lb.ft/N-m) | p. 107 |
| Fuel Injection Timing (B.T.D.C.) | 6 degrees | p. 6 |
| Valve Clearance (Cold, Intake & Exhaust) | 0.40 mm (0.016 in) | p. 6 |
| Low Idle Speed | 675 - 725 rpm | p. 6 |
| Lubricating Oil Volume | 7.5 L (1.98 US/gal) | p. 6 |
| Flywheel Bolt Torque | 113 - 123 N-m | p. 12 |
| Injection Nozzle Pressure | 150 kg/cm² (14.7 MPa) | p. 23 |
