The Kubota D1503-M-DI is a 1.5 L (1,499 cc, 91.44 cu·in) straight-three, water-cooled naturally aspirated vertical diesel engine manufactured by Kubota.
The Kubota D1503-M-DI engine has a Troiddal type сombustion сhamber (Direct Injection), the Bosch “K”-type mini mini fuel injection pump and Bosch “P”-type hole fuel injection nozzle. The cylinder bore and the piston stroke are 83.0 mm (3.27) in and 92.4 mm (3.64 in), respectively. The compression ratio rating is 20.0:1.
The D1503-M-DI diesel engine produced 32.0 PS (23.5 KW; 31.5 HP) at 2,800 rpm of net horsepower.
The breakdown of the engine code is as follows:
- D – 3-cylinders
- 15 – Approximate displacement 1500 cc
- DI – Direct Injection
General information
| Engine Specifications | |
| Engine code | D1503-M-DI |
| Layout | Straight-3, vertical diesel engine |
| Fuel type | Diesel fuel No.2-D |
| Production | – |
| Displacement | 1.5 L, 1,499 cm3 (91.44 cu in) |
| Fuel injection pump | Bosch “K”-type mini injection pump |
| Fuel nozzle | Bosch “P”-type hole |
| Starting system | Electric starting with 12V (1.4 kW) starter |
| Starting support device | Glow plug |
| Governor | Centrifugal mechanical governor |
| Power adder | None |
| Max. Horsepower |
Net (intermittent): 32.0 PS (23.5 KW; 31.5 HP) at 2,800 rpm Gross (intermittent): 33.7 PS (24.8 KW; 33.3 HP) at 2,800 rpm |
| Torque output | – |
| Firing order | 1-2-3 |
| Dimensions (L x W x H): | 599 x 514 x 643 mm (23.6 x 20.2 x 25.3 in) |
| Weight | 148.0 kg (326.0 lbs) |
Cylinder block
| Cylinder block | ||
| Compression ratio: | 20.0:1 | |
| Cylinder bore: | 83.0 mm (3.27 in) | |
| Piston stroke: | 92.4 mm (3.64 in) | |
| Number of piston rings (compression / oil): | 2 / 1 | |
| Cylinder inner diameter: | 83.000-83.022 mm (3.2677-3.2686 in) | |
| Piston skirt diameter | – | |
| Piston ring side clearance: | Second | 0.093-0.128 mm (0.0037-0.0050 in) |
| Oil | 0.020-0.060 mm (0.0008-0.0023 in) | |
| Piston ring end gap: | Top | 0.200-0.350 mm (0.0080-0.0138 in) |
| Second | 0.300-0.450 mm (0.0118-0.0177 in) | |
| Oil | 0.250-0.450 mm (0.0099-0.0177 in) | |
| Piston pin outer diameter | 23.002-23.011 mm (0.9056-0.9059 in) | |
| Crankshaft main journal diameter: |
S/n below 3R9999: 51.921-51.940 mm (2.0441-2.0449 in) S/n above 3S0001: 59.921-59.940 mm (2.3590-2.3598 in) |
|
| Crankpin diameter: | 46.959-46.975 mm (1.8487-1.8494 in) | |
Cylinder head
| Cylinder head | ||
| Valve Arrangement: | OHV, gear drive | |
| Valves: | 6 (2 valves per cylinder) | |
| Valve timing: | INTAKE | – |
| EXHAUST | – | |
| Valve seat width: | INTAKE | 2.120 mm (0.0835 in) |
| EXHAUST | 2.120 mm (0.0835 in) | |
| Valve stem diameter: | INTAKE | 7.960-7.975 mm (0.3134-0.3140 in) |
| EXHAUST | 7.960-7.975 mm (0.3134-0.3140 in) | |
| Valve spring free length: | INTAKE | 41.7-42.2 mm (1.6417-1.6614 in) |
| EXHAUST | 41.7-42.2 mm (1.6417-1.6614 in) | |
| Camshaft cam height: | INTAKE | 33.900 mm (1.3346 in) |
| EXHAUST | 33.900 mm (1.3346 in) | |
| Camshaft journal diameter: | 39.934-39.950 mm (1.5722-1.5728 in) | |
Tightening torque
| Tightening torque specs | |
| Rocker arm bracket screw: | 23.5-27.5 Nm (2.4-2.8 kgf-m, 17.4-20.3 lb-ft) |
| Cylinder head: | 93.1-98.0 Nm (9.5-10.0 kgf-m, 68.7-72.3 lb-ft) |
| Nozzle holder clamp screw: | 25.5-29.5 Nm (2.4-2.8 kgf-m, 17.4-20.3 lb-ft) |
| Connecting rod screw: | 44.1-49.0 Nm (4.5-5.0 kgf-m, 32.5-36.2 lb-ft) |
| Flywheel bolts: | 98.1-107.9 Nm (10.0-11.0 kgf-m, 72.3-79.6 lb-ft) |
| Main bearing case screw 1: | 46.1-50.9 Nm (4.7-5.2 kgf-m, 34.0-37.6 lb-ft) |
| Main bearing case screw 2: | 68.6-73.5 Nm (7.0-7.5 kgf-m, 50.6-54.2 lb-ft) |
Maintenance data
| Valve clearance | |
| Intake valve | 0.18-0.22 mm (0.0071-0.0087 in) |
| Exhaust valve | 0.18-0.22 mm (0.0071-0.0087 in) |
| Compression pressure | |
| Standard | 30.0-33.0 kgf/cm2 (2.94-3.24 MPa, 427-469 psi) |
| Oil system | |
| Recommended engine oil | CD or CE |
| SAE Viscosity Number | SAE 10W-30, 10W-40 |
| Engine oil capacity |
Oil pan depth 90.0 mm (3.54 in): 5.6 L (1.5 US gal, 1.2 Imp. gal) Oil pan depth 124.0 mm (4.88 in): 7.0 L (1.8 US gal, 1.5 Imp. gal) |
| Fuel system | |
| Injection timing: | 10.5-12.5° B.T.D.C. |
| Fuel injection pressure |
1st stage: 18.6 MPa (190 kgf/cm2, 2702 psi) 2st stage: 22.6 MPa (230 kgf/cm2, 3270 psi) |
| Cooling system | |
| 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: | 5.5 liters (1.5 US gal, 1.2 Imp. gal) |
| Electrical system | |
| Battery: | 12V, 60A (75D31R) |
| Alternator brush Length (std/min): | 10.5 mm (0.4130 in) / 8.4 mm (0.3310 in) |
| Glow plug resistance: | Approx 1.0 Ω |
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