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Isuzu 3CD1 Engine

The Isuzu 3CD1 is a heavy-duty, vertical, 3-cylinder, 4-cycle water-cooled diesel engine designed for industrial, agricultural, and construction applications. Known for its compact footprint and robust design, it features a highly efficient direct injection combustion system. The engine is deployed either as a naturally aspirated unit or a turbocharged version designated as the 3CD1T. It complies with stringent off-road emissions regulations, including Interim Tier-4 and Stage-IIIA standards.

The engine employs an overhead valve (OHV) arrangement driven by a gear-train-actuated camshaft. It uses a standard configuration of 2 valves per cylinder (1 intake, 1 exhaust), totaling 6 valves for the entire engine block. Valve clearance adjustments must be performed mechanically at the rocker arms according to the maintenance schedule. The nominal cylinder dimensions are a bore of 84.0 mm (3.30 inches) and a stroke of 90.0 mm (3.54 inches). Total engine displacement measures exactly 1.5 liters (1496 cc).

The 3CD1 utilizes a direct injection (DI) fuel system where fuel is atomized directly into the piston crown combustion bowl. It is equipped with a high-precision, mechanical in-line fuel injection pump assembly and an integrated mechanical governor assembly to control engine speed under variable loads. The delivery side consists of high-pressure steel lines routing fuel to multi-hole injection nozzles, supported by a low-pressure circuit containing a fuel feed pump, water separator, and a replaceable primary fuel filter element.

Lubrication is managed via a forced-pressure feed system powered by a trochoid-type oil pump driven directly by the crankshaft gear train. The system includes a full-flow, spin-on oil filter cartridge, an internal pressure-regulating relief valve, and an oil pressure switch. High-grade diesel engine oil meeting API specifications is mandatory to protect internal journals and bearing surfaces.

Engine temperature is regulated by a liquid-forced circulation cooling system. A centrifugal, belt-driven water pump circulates coolant through the cylinder block and cylinder head passages. The system incorporates a wax-pellet type thermostat to manage optimal engine operating temperatures and an engine-driven cooling fan to draw air through the radiator core.

General Technical Data

Engine Specifications

Engine Model ............... Isuzu 3CD1
Engine Type ............... 4-cycle inline 3-cylinder indirect injection liquid-cooled diesel
Number of Cylinders ............... 3
Cylinder Arrangement ............... In-line vertical
Engine Bore, in (mm) ............... 3.30 (84.0)
Engine Stroke, in (mm) ............... 3.54 (90.0)
Displacement, cu.in (L) ............... 91.3 (1.496)
Rated Engine Power, hp (kW) ............... 21.3-38.9 (15.9-29.0)
Rated Engine Speed, rpm ............... 1800-3000
Peak Torque ............... 79.7 lb-ft (108.0 Nm) at 1800 rpm
Low Idle Speed, rpm ............... 800-950
High Idle Speed, rpm ............... 3150-3250
Aspiration Type ............... Naturally Aspirated
Compression Ratio ............... 21.5:1-23.0:1
Firing Order ............... 1-3-2
Direction of Rotation ............... Counterclockwise viewed from flywheel
Combustion Chamber Type ............... Swirl chamber type indirect injection
Cylinder Block Type ............... Monoblock cast iron
Cylinder Head Type ............... Single-piece cast iron overhead valve
Lubrication System ............... Forced pressure feed by trochoid gear pump
Oil Pump Type ............... Trochoid gear-driven type
Oil Filter Type ............... Full-flow cartridge spin-on
Cooling System ............... Liquid-cooled forced circulation
Water Pump Type ............... Belt-driven centrifugal impeller
Air Cleaner Type ............... Dry element dual stage
Starting System ............... Electric starter motor induction type
Electrical System Voltage, V ............... 12
Alternator Capacity, A ............... 20-50

Fuel System

Fuel Injection Pump Type ............... Bosch PFR type in-line mini pump
Fuel Injection Nozzle Type ............... Throttle type nozzle pintle construction
Fuel Feed Pump Type ............... Mechanical diaphragm type or electric solenoid
Injection Start Pressure, psi (MPa) ............... 1991-2132 (13.7-14.7)
Main Fuel Filter Type ............... Spin-on cartridge with integrated water separator
Fuel Transfer Pump Pressure, psi (kPa) ............... 2.9-5.8 (20.0-40.0)
Injection Timing, deg ............... 14-18 before top dead center
Fuel Return Line Configuration ............... Overhead overflow pipe collection
Governor Type ............... Mechanical centrifugal type
Maximum Fuel Inlet Restriction, in Hg (kPa) ............... 4.0 (13.5)
Maximum Fuel Return Restriction, in Hg (kPa) ............... 5.9 (20.0)
Fuel Injection Pipe Outer Diameter, in (mm) ............... 0.24 (6.0)
Fuel Injection Pipe Inner Diameter, in (mm) ............... 0.08 (2.0)

Dimensions and Weight

Overall Length, in (mm) ............... 21.8-23.9 (555-605)
Overall Width, in (mm) ............... 20.0-20.4 (510-520)
Overall Height, in (mm) ............... 26.8 (680)
Dry Weight, lbs (kg) ............... 326-346 (148-157)
Wet Weight, lbs (kg) ............... 352-372 (160-169)

Maintenance Data

Service Information

Cylinder Compression Pressure, Standard, psi (MPa) ............... 427 (2.94)
Cylinder Compression Pressure, Limit, psi (MPa) ............... 341 (2.35)
Maximum Variance Between Cylinders, psi (MPa) ............... 43 (0.30)
Lubricating Oil Pressure at Idle, psi (kPa) ............... 14.2 (98.0)
Lubricating Oil Pressure at Rated Speed, psi (kPa) ............... 42.7-56.9 (294.0-392.0)
Coolant Thermostat Opening Temperature, F (C) ............... 169-176 (76-80)
Coolant Thermostat Full Open Temperature, F (C) ............... 194 (90)
Cooling System Operating Pressure, psi (kPa) ............... 13.0 (90.0)
Fan Belt Deflection Outer Force 22 lbs, in (mm) ............... 0.39-0.47 (10.01-12.0)
Intake Valve Lash, Cold, in (mm) ............... 0.0079 (0.20)
Exhaust Valve Lash, Cold, in (mm) ............... 0.0079 (0.20)

Engine Oil and Coolant

Engine Oil Type .................. SAE 30, 10W-30, or SAE 15W-40
API Service Classifications ......................... CC, CD, CE, or CF-4
Engine Oil Capacity with Filter, qt (L) ............... 6.66 (6.30)
Engine Oil Capacity, Base Pan Only, qt (L) ............... 6.02 (5.70)
Coolant Capacity, Engine Block Only, qt (L) ............... 2.43 (2.30)

Service Intervals

Change oil and filter ............... Every 250 hours
Inspect air cleaner ............... Every 100 hours
Service air cleaner ............... Every 500 hours
Replace fuel filter ............... Every 500 hours
Valve clearance adjustment ............... Every 1000 hours
Fuel system inspection ............... Every 1000 hours
Change coolant ............... Every 2000 hours
Compression test ............... Every 1000 hours
Belt inspection ............... Every service cycle

Service Specifications

Cylinder Bore Diameter (Standard), in (mm) ............... 3.3071-3.3083 (84.000-84.030)
Cylinder Bore Roundness Out-Of-Round, in (mm) ............... 0.0012 (0.030)
Cylinder Bore Taper, Repair Limit, in (mm) ............... 0.0012 (0.030)
Cylinder Block Main Bearing Bore I.D., in (mm) ............... 2.2047-2.2055 (56.000-56.020)
Cylinder Block Camshaft Bearing Bore I.D., in (mm) ............... 1.6929-1.6941 (43.000-43.030)
Crankshaft Main Journal Outer Diameter, in (mm) ............... 2.0457-2.0465 (51.960-51.980)
Crankshaft Crankpin Journal Outer Diameter, in (mm) ............... 1.8882-1.8890 (47.960-47.980)
Crankshaft Main Bearing Clearance, in (mm) ............... 0.0014-0.0031 (0.035-0.080)
Crankshaft Crankpin Bearing Clearance, in (mm) ............... 0.0014-0.0029 (0.035-0.074)
Crankshaft End Play, in (mm) ............... 0.0024-0.0094 (0.060-0.240)
Connecting Rod Small End Bushing I.D., in (mm) ............... 0.9846-0.9854 (25.010-25.030)
Connecting Rod Big End Play, in (mm) ............... 0.0059-0.0138 (0.150-0.350)
Cylinder Head Lower Surface Flatness Surface, in (mm) ............... 0.0020 (0.050)
Valve Guide Inside Diameter (Intake), in (mm) ............... 0.2756-0.2764 (7.000-7.020)
Valve Guide Inside Diameter (Exhaust), in (mm) ............... 0.2756-0.2764 (7.000-7.020)
Valve Stem Outer Diameter (Intake), in (mm) ............... 0.2724-0.2732 (6.920-6.940)
Valve Stem Outer Diameter (Exhaust), in (mm) ............... 0.2713-0.2720 (6.890-6.910)
Valve Stem To Guide Clearance (Intake), in (mm) ............... 0.0024-0.0039 (0.060-0.100)
Valve Stem To Guide Clearance (Exhaust), in (mm) ............... 0.0035-0.0051 (0.090-0.130)
Valve Spring Free Length (Standard), in (mm) ............... 1.6890 (42.900)
Valve Spring Free Length (Wear Limit), in (mm) ............... 1.6299 (41.400)
Rocker Arm Shaft Outer Diameter, in (mm) ............... 0.5894-0.5902 (14.971-14.992)
Rocker Arm Bushing Inner Diameter, in (mm) ............... 0.5906-0.5913 (15.002-15.020)
Rocker Arm Oil Clearance Bushing To Shaft, in (mm) ............... 0.0004-0.0019 (0.010-0.049)
Camshaft Journal Outer Diameter, Front, in (mm) ............... 1.6913-1.6921 (42.960-42.980)
Camshaft Journal Outer Diameter, Middle, in (mm) ............... 1.6913-1.6921 (42.960-42.980)
Camshaft Journal Outer Diameter, Rear, in (mm) ............... 1.6913-1.6921 (42.960-42.980)
Camshaft Bearing Oil Clearance, in (mm) ............... 0.0008-0.0028 (0.020-0.070)
Cam Lobe Height (Intake), in (mm) ............... 1.3248-1.3268 (33.650-33.700)
Cam Lobe Height (Exhaust), in (mm) ............... 1.3248-1.3268 (33.650-33.700)
Camshaft End Play, in (mm) ............... 0.0020-0.0059 (0.050-0.150)
Piston Outer Diameter, in (mm) ............... 3.3047-3.3059 (83.940-83.970)
Piston To Cylinder Bore Clearance, in (mm) ............... 0.0024-0.0035 (0.060-0.090)
Piston Pin Bore Inner Diameter, in (mm) ............... 0.9843-0.9846 (25.002-25.010)
Piston Pin Outer Diameter, in (mm) ............... 0.9839-0.9843 (24.992-25.000)
Piston Pin To Piston Pin Bore Clearance, in (mm) ............... 0.0001-0.0007 (0.002-0.018)
Piston Pin To Connecting Rod Bushing Clearance, in (mm) ............... 0.0004-0.0015 (0.010-0.038)
Top Ring Side Clearance, in (mm) ............... 0.0020-0.0035 (0.050-0.090)
Second Ring Side Clearance, in (mm) ............... 0.0016-0.0031 (0.040-0.080)
Oil Ring Side Clearance, in (mm) ............... 0.0008-0.0024 (0.020-0.060)
Top Ring End Gap, in (mm) ............... 0.0079-0.0138 (0.200-0.350)
Second Ring End Gap, in (mm) ............... 0.0079-0.0138 (0.200-0.350)
Oil Ring End Gap, in (mm) ............... 0.0079-0.0157 (0.200-0.400)
Tappet Cylinder Block Bore Inner Diameter, in (mm) ............... 0.8268-0.8276 (21.000-21.021)
Tappet To Cylinder Block Bore Clearance, in (mm) ............... 0.0012-0.0032 (0.030-0.081)

Tightening Torques

Cylinder Head Bolt (First Stage), lb-ft (Nm) ............... 21.7 (29.4)
Cylinder Head Bolt (Second Stage), lb-ft (Nm) ............... 43.4 (58.8)
Cylinder Head Bolt (Final Stage), lb-ft (Nm) ............... 61.5-68.7 (83.4-93.2)
Connecting Rod Cap Bolt, lb-ft (Nm) ............... 36.2-43.4 (49.0-58.8)
Main Bearing Cap Bolt, lb-ft (Nm) ............... 57.9-65.1 (78.5-88.3)
Flywheel Retaining Bolt, lb-ft (Nm) ............... 57.9-65.1 (78.5-88.3)
Crankshaft Center Pulley Bolt, lb-ft (Nm) ............... 86.8-94.0 (117.7-127.5)
Camshaft Thrust Plate Retaining Screw, lb-ft (Nm) ............... 11.2-17.3 (15.2-23.5)
Rocker Arm Shaft Bracket, lb-ft (Nm) ............... 17.4-24.6 (23.5-33.3)
Cylinder Head Cover Cap Nut, lb-ft (Nm) ............... 5.8-8.7 (7.8-11.8)
Oil Pan Drain Plug, lb-ft (Nm) ............... 36.2-43.4 (49.0-58.8)
Oil Pan Flange Perimeter Mounting Bolt, lb-ft (Nm) ............... 11.2-17.3 (15.2-23.5)
Exhaust Manifold Stud Flange Nut, lb-ft (Nm) ............... 17.4-24.6 (23.5-33.3)
Intake Manifold Securing Bolt, lb-ft (Nm) ............... 11.2-17.3 (15.2-23.5)
Fuel Injection Pump Mounting Nut, lb-ft (Nm) ............... 14.5-21.7 (19.6-29.4)
Fuel Injection Pump Gear Drive Locknut, lb-ft (Nm) ............... 28.9-36.2 (39.2-49.0)
Fuel Injection Nozzle Holder Assembly Cap, lb-ft (Nm) ............... 43.4-50.6 (58.8-68.6)
Fuel Injection Pipe Flare Nut, lb-ft (Nm) ............... 18.1-21.7 (24.5-29.4)
Fuel Leak-Off Rail Spill Line Nut, lb-ft (Nm) ............... 14.5-21.7 (19.6-29.4)
Glow Plug Terminal Thread Hex Nut, lb-ft (Nm) ............... 1.4-2.2 (2.0-3.0)
Oil Pressure Switch Sensor Unit, lb-ft (Nm) ............... 10.8-14.5 (14.7-19.6)
Fresh Water Pump Body Securing Bolt, lb-ft (Nm) ............... 11.2-17.3 (15.2-23.5)
Cooling Fan Blade Mounting Center Bolt, lb-ft (Nm) ............... 5.8-8.7 (7.8-11.8)
Thermostat Housing Cover Assembly Hex Bolt, lb-ft (Nm) ............... 11.2-17.3 (15.2-23.5)
Starter Motor Housing Mounting Bolt, lb-ft (Nm) ............... 36.2-43.4 (49.0-58.8)
Alternator Mounting Bracket Primary Pivot Bolt, lb-ft (Nm) ............... 28.9-36.2 (39.2-49.0)
Alternator Adjusting Link Lock Slotted Bolt, lb-ft (Nm) ............... 14.5-21.7 (19.6-29.4)
Flywheel Housing Perimeter Mounting Bolt, lb-ft (Nm) ............... 36.2-43.4 (49.0-58.8)
Oil Pump Cover Plate Retaining Screws, lb-ft (Nm) ............... 5.8-8.7 (7.8-11.8)
Oil Pressure Relief Valve Plug, lb-ft (Nm) ............... 28.9-36.2 (39.2-49.0)

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• Isuzu Engines Specs
  
• Isuzu 2AA1 Specs
  
• Isuzu 3AA1 Specs
  
• Isuzu 3AB1 Specs
  
• Isuzu 3CB1 Specs
  
• Isuzu 3CE1 Specs
  
• Isuzu 3CH1 Specs
  

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