The Kubota D782-E is a 0.78 L (778 cc, 47.5 cu·in) straight-three, water-cooled naturally aspirated diesel engine manufactured by Kubota.
The Kubota D782-E engine has a spherical type сombustion сhamber with glow plug, Bosch MD mini fuel injection pump, and Bosch throttle type injection nozzle.
The compression ratio rating is 24.0:1. Cylinder bore is 67.0 mm (2.64 in) and the piston stroke is 73.6 mm (2.9 in).
The D782-E diesel engine produced 18.4 PS (13.5 KW; 18.1 HP) at 3,200 rpm of net (intermittent) horsepower and 15.9 PS (11.7 KW; 15.7 HP) at 3,200 rpm of net (continuous) horsepower.
The breakdown of the engine code is as follows:
- D – 3-cylinders
- 78 – Approximate displacement 780 cc
- 2 – Super-Mini series
- E – EPA/CARB Tier 1 level
General information
Engine Specifications | |
Engine code | D782-E |
Layout | Straight-3, vertical diesel engine |
Fuel type | Diesel fuel No.2-D |
Production | – |
Displacement | 0.78 L, 778 cm3 (47.5 cu in) |
Max. Horsepower |
Net (intermittent): 18.4 PS (13.5 KW; 18.1 HP) at 3,200 rpm Net (continuous): 15.9 PS (11.7 KW; 15.7 HP) at 3,200 rpm |
Torque output | – |
Injection type | Indirect injection |
Cooling system | Liquid-cooled |
Fuel injection pump | Bosch MD type mini fuel injection pump |
Fuel nozzle | Bosch throttle type |
Starting system | Electric starting with 12V (0.8 kW) starter |
Starting support device | Glow plug in combustion chamber |
Governor | Centrifugal ball mechanical governor |
Power adder | None |
Firing order | 1-2-3 |
Dimensions (L x W x H): | 426 x 398 x 519 mm (16.8 x 15.7 x 20.4 in) |
Weight | 63.5 kg (140.0 lbs) |
Cylinder block
Cylinder block | ||
Compression ratio: | 24.0:1 | |
Cylinder bore: | 67.0 mm (2.64 in) | |
Piston stroke: | 73.6 mm (2.9 in) | |
Number of piston rings (compression / oil): | 2 / 1 | |
Cylinder inner diameter: | 67.000-67.019 mm (2.6378-2.6385 in) | |
Piston skirt diameter | – | |
Piston ring side clearance: | Second | 0.085-0.112 mm (0.0033-0.0044 in) |
Oil | 0.020-0.060 mm (0.0008-0.0024 in) | |
Piston ring end gap: | Top | 0.150-0.300 mm (0.0059-0.0118 in) |
Second | 0.300-0.450 mm (0.0118-0.0177 in) | |
Oil | 0.150-0.300 mm (0.0059-0.0118 in) | |
Piston pin outer diameter | 20.002-20.011 mm (0.7875-0.7878 in) | |
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 diameter: | 33.959-33.975 mm (1.337-1.3376 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 | 5.968-5.980 mm (0.2349-0.2354 in) |
EXHAUST | 5.968-5.980 mm (0.2349-0.2354 in) | |
Valve spring free length: | INTAKE | 31.6 mm (1.2441 in) |
EXHAUST | 31.6 mm (1.2441 in) | |
Camshaft lobe height: | INTAKE | 26.88 mm (1.0583 in) |
EXHAUST | 26.88 mm (1.0583 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) |
Maintenance data
Valve clearance | |
Intake valve | 0.145-0.185 mm (0.0057-0.0073 in) |
Exhaust valve | 0.145-0.185 mm (0.0057-0.0073 in) |
Compression pressure | |
Standard | 2.84-3.24 MPa, 29-33 kgf/cm2, 412-469 psi |
Oil system | |
Recommended engine oil | CD or CE |
SAE Viscosity Number | SAE 10W-30, 10W-40 |
Engine oil capacity | 3.6 L (3.8 US. qt, 3.17 Imp. qt.) |
Fuel system | |
Injection timing: | 20° |
Fuel injection pressure | 13.73-14.71 MPa (140-150 kgf/cm2, 1991-2133 psi) |
Cooling system | |
Coolant capacity | 3.1 liters (3.3 US.qts, 2.7 Imp. qts) |
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) |
Electrical system | |
Battery: | 12V, 35Ah 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) |
We try to use verified sources and official documentation, however, differences between sources or errors in entering information may occur. We do not provide advice on technical issues related to the engines operation or repair. We do not recommend using provided information for engines repairing engines or spare parts ordering, use only official service manuals and spare-parts catalogs.
Kubota rates this engine at 17 hp sometimes and 21hp at other times …. So what is true ?? IN there GR2120 lawn tractor ???
This depends on the modification of the engine to meet environmental standards
On my ZD-21 ZTR mower the difference is due to the governed RPM. The ZD-21 engine is governed to run at 3200 RPM. At this speed, it produces about 18 HP. But Kubota labels the mower a ZD-21 because 1) that is the engine power when governed at 3600 RPM. A bit of a scam, but not one that bothers me. The ZD-21 title simply sounds a bit better and might help sell what is already a truly excellent mower. I’ve had mine for going on 24 years now and the little engine has never needed repairs–not even a glow plug. It is usually run wide open. Truly amazing.