The Kubota D722-E4 is a 719 cc (43.9 cu·in) natural aspirated three-cylinders four-stroke liquid-cooled internal combustion vertical diesel engine, manufactured by Kubota for general-purpose applications.
The cylinder bore and piston stroke are 67.0 mm (2.64 in) and 68.0 mm (2.68 in), respectively. The compression ratio rating is 23.5:1.
The D722-E4 engine produced 19.0 PS (14.0 KW; 18.8 HP) at 3,600 rpm of the net (intermittent) horsepower.
The Kubota D722-E4 features:
- High durability tunnel-type cylinder block
- Aluminum alloy pistons
- Spherical type combustion chamber
- Bosch MD-type mini fuel injection pump
- Bosch throttle type injection nozzle
- Centrifugal ball mechanical governor
- Forced lubrication by pump
- Liquid cooling system
- Electric starter (12V, 0.8 kW)
General information
| Engine Specifications | |
| Engine model | D722-E4 |
| Engine type | 4-stroke, vertical, three-cylinders |
| Displacement | 719 cm3, (43.9 cu·in) |
| Max. horsepower | Stand-by: 18.1 PS (13.3 KW; 17.8 HP) at 3,600 rpm Net (intermittent): 19.0 PS (14.0 KW; 18.8 HP) at 3,600 rpm Net (сontinuous): 16.6 PS (12.2 KW; 16.4 HP) at 3,600 rpm |
| Max. torque | – |
| Emission type | EPA/CARB Tier 4 (NRTC/NTE test mode) + Stage V ready |
| Cooling system | Liquid-cooled |
| Lubricating system | Forced lubrication by pump |
| Combustion chamber | Spherical type (E-TVCS) |
| Fuel injection pump | Bosch MD type mini pump |
| Injection type | Indirect injection |
| Injection nozzle | Bosch throttle type |
| Fuel used | Diesel fuel No.2-D |
| Starting system | Electric starter (12V, 0.8 kW) |
| Starting support device | Glow plug in combustion chamber |
| Governor | Centrifugal ball mechanical governor |
| PTO shaft rotation | Counterclockwise (from PTO shaft side) |
| Dimensions (L x W X H) | 407 x 386 x 564 mm (16.0 x 15.2 x 22.2 in) |
| Dry weight | 63.7 kg (140.4 lbs) |
Cylinder Block and Head
| Cylinder block | |
| Compression ratio: | 23.5:1 |
| Cylinder bore: | 67.0 mm (2.64 in) |
| Piston stroke: | 68.0 mm (2.68 in) |
| Cylinder internal diameter (standard): | 67.000-67.019 mm (2.6378-2.6385 in) |
| Number of piston rings (compression / oil): | 2/1 |
| Connecting rod small end diameter (standard): | 20.025-20.040 mm (0.7884-0.789 in) |
| Piston pin diameter: | 20.002-20.040 mm (0.7875-0.789 in) |
| Side clearance (Second): | 0.090-0.120 mm (0.0035-0.0047 in) |
| Side clearance (Oil): | 0.040-0.080 mm (0.0016-0.0031 in) |
| Ring end gap (Top): | 0.150-0.300 mm (0.0059-0.0118 in) |
| Ring end gap (Second): | 0.300-0.450 mm (0.0118-0.0177 in) |
| Ring end gap (Oil): | 0.150-0.350 mm (0.0059-0.0130 in) |
| Number of main bearings: | 4 |
| Crankshaft main journal diameter: | Flywheel side: 43.934-43.950 mm (1.72969-1.73032 in) Other: 39.934-39.950 mm (1.5722-1.5728 in) |
| Crankpin journal diameter: | 33.959-33.975 mm (1.337-1.3376 in) |
| Cylinder head | |
| Valves: | 2,(6 valves in total) |
| Valve timing (INTAKE): | – |
| Valve timing (EXHAUST): | – |
| Valve seat width (INTAKE): | 2.120 mm (0.0835 in) |
| Valve seat width (EXHAUST): | 2.120 mm (0.0835 in) |
| Value seat angle (INTAKE): | 45° |
| Value seat angle (EXHAUST): | 45° |
| Valveface angle (INTAKE): | 45° |
| Valveface angle (EXHAUST): | 45° |
| Valve steam diameter (INTAKE): | 5.968-5.980 mm (0.2349-0.2354 in) |
| Valve steam diameter (EXHAUST): | 5.968-5.980 mm (0.2349-0.2354 in) |
| Valve spring free length (INTAKE): | 31.300-31.800 mm (1.2400-1.2500 in) |
| Valve spring free length (EXHAUST): | 31.300-31.800 mm (1.2400-1.2500 in) |
| Tappet outer diameter: | 17.966-17.984 mm (0.7073-0.7080 in) |
| Rocker arm shaft outer diameter: | 10.473-10.484 mm (0.4123-0.4127 in) |
| Camshaft lobe height (INTAKE): | 26.880 mm (1.0583 in) |
| Camshaft lobe height (EXHAUST): | 25.880 mm (1.0190 in) |
| Camshaft journal diameter: | 32.934-32.950 mm (1.2966-1.2972 in) |
Tightening torque
| Tightening torque specs | |
| Head cover cap nuts (M6x1.0): | 3.9-5.3 Nm (0.4-0.6 kgf-m, 2.9-4.3 lb-ft) |
| Head bolts (M8x1.25): | 39.2-44.1 Nm (4.0-4.5 kgf-m, 28.9-32.5 lb-ft) |
| Main bearing case bolts 1 (M6x1.0): | 12.7-15.7 Nm (1.3-1.6 kgf-m, 9.4-11.6 lb-ft) |
| Main bearing case screw 2 (M7x1.0): | 26.5-30.4 Nm (2.7-3.1 kgf-m, 19.5-22.4 lb-ft) |
| Flywheel bolts (M10x1.25): | 53.9-58.8 Nm (5.5-6.0 kgf-m, 39.8-43.4 lb-ft) |
| Connecting rod bolts (M7x0.75): | 26.5-30.4 Nm (2.7-3.1 kgf-m, 19.5-22.4 lb-ft) |
| Rocker arm bracket nuts (M6x1.0): | 9.81-11.28 Nm (1.0-1.15 kgf-m, 7.23-8.32 lb-ft) |
| Idle gear shaft bolts (M6x1.0): | 9.8-11.3 Nm (1.00-1.15 kgf-m, 7.2-8.3 lb-ft) |
| Idle gear shaft screws (M6x1.0): | 9.8-11.3 Nm (1.00-1.15 kgf-m, 7.2-8.3 lb-ft) |
| Glow plugs (M8x1.0): | 7.8-14.7 Nm (0.8-1.5 kgf-m, 5.8-10.8 lb-ft) |
| Nozzle holder assembly (M20x1.5): | 49.0-68.6 Nm (5.0-7.0 kgf-m, 36.2-50.6 lb-ft) |
| Nozzle holder and nozzle retaining nut: | 58.8-78.5 Nm (6.0-8.0 kgf-m, 43.4-57.9 lb-ft) |
| Injection pipe retaining nuts: | 24.5-34.3 Nm (2.5-3.5 kgf-m, 18.1-25.3 lb-ft) |
Service Data
| Engine | |
| Maximum speed: | 3800 rpm |
| Idle speed: | 900-1000 rpm |
| Cylinder compression: | 29.0-33.0 kgf/cm2 (2.84-3.24 MPa, 412-469 psi) |
| Compression differential limit between cylinders: | 10% or less |
| Valve clearance | |
| Intake valve clearance: | 0.145-0.185 mm (0.0057-0.0073 in) |
| Exhaust valve clearance: | 0.145-0.185 mm (0.0057-0.0073 in) |
| Oil system | |
| Lubrication system: | Forced lubrication by pump |
| Oil type: | API CD or CE |
| Oil capacity: | Oil pan depth 101 mm (3.98 in): 3.2 L (3.38 US. qt, 2.82 Imp. qt.) Oil pan depth 121 mm (4.76 in): 3.8 L (4.00 US. qt, 3.31 Imp. qt.) |
| Oil filter: | Full flow paper filter (cartridge type) |
| Oil pressure: | At idle spped: 98 kPa (1.0 kgf/cm2, 14 psi) At rated speed: 196-441 kPa (2.0-4.5 kgf/cm2, 29-64 psi) |
| Fuel system | |
| Fuel injection pump | Bosch MD-type mini pump |
| Injection nozzle | Bosch throttle type |
| Injection timing: | – |
| Fuel injection pressure | 13.73-14.71 MPa (140-150 kgf/cm2, 1991-2133 psi) |
| Cooling system | |
| Type: | Pressurized radiator, forced circulation with water pump (not included in the basic engine) |
| Thermostat’s valve opening temperature: | 69.5-72.5°C (157.1-162.5°F) |
| Temperature at which thermostat completely opens: | 85°C (185°F) |
| Coolant capacity | 3.1 liters (3.3 US.qts, 2.7 Imp. qts) |
| Electrical system | |
| Battery: | 12V, 36AH or equivalent |
| Starter mica undercut: | 0.5-0.8 mm (0.0197-0.0315 in) |
| Starter brush length: | 16.0 mm (0.6299 in) |
| Alternator (no-load voltage): | AC 20V at 5,200 rpm |
| Glow plug resistance: | Approx 0.9 Ω |
| Alternator stator resistance: | Less than 1.0 Ω |
| Alternator rotor resistance: | Less than 2.9 Ω |
| Alternator slip ring: | 14.4 mm (0.567 in) |
| Alternator brush Length: | 10.5 mm (0.413 in) |
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