The Kubota Z482-B(E) is a 0.48 L (479 cc, 29.2 cu·in) straight-two, water-cooled naturally aspirated vertical diesel engine from the 68 mm stroke series, manufactured by Kubota.
The Kubota Z482-B(E) engine has a spherical type сombustion сhamber (N-TVCS on engine with s/n 489290 or lower or E-TVCS on engine with s/n 489291 or higher) with glow plug, Bosch MD mini fuel injection pump, and Bosch throttle type injection nozzle.
The compression ratio rating is 23.0:1. Cylinder bore is 67.0 mm (2.64 in) and the piston stroke is 68.0 mm (2.68 in).
The Z482-B(E) diesel engine produced 12.6 PS (9.3 KW; 12.5 HP) at 3,600 rpm of net (intermittent) horsepower, 14.1 PS (10.4 kW; 13.9 HP) at 3,600 rpm of gross (intermittent) horsepower and 29.7 Nm (3.03 kg·m; 21.92 ft·lb) at 2,600 rpm of torque.
The breakdown of the engine code is as follows:
- Z – 2-cylinders
- 48 – Approximate displacement 480 cc
- 2 – 68 mm stroke series
- B(E) – Early industrial diesel
General information
| Engine Specifications | |
| Engine code | Z482-B(E) |
| Layout | Straight-2, vertical diesel engine |
| Fuel type | Diesel fuel No.2-D |
| Production | – |
| Displacement | 0.48 L, 479 cm3 (29.2 cu in) |
| Max. Horsepower | Net (intermittent): 12.6 PS (9.3 KW; 12.5 HP) at 3,600 rpm Gross (intermittent): 14.1 PS (10.4 kW; 13.9 HP) at 3,600 rpm |
| Torque output | 29.7 Nm (3.03 kg·m; 21.92 ft·lb) at 2,600 rpm |
| 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 |
| Dimensions (L x W x H): | 351 x 398 x 519 mm (13.8 x 15.7 x 20.4 in) |
| Weight | 53.1 kg (117.1 lbs) |
Cylinder block
The Kubota Z482-B(E) diesel engine has a high durability tunnel-type cylinder block in which the crank bearing component is a constructed body.
The crankshaft is made of tough special alloy steel, and the journals, pins and oil seal sliding portions are induction hardened. The front journal is supported by a solid type bearing, the intermediate journal by a split type, and the rear journal by a split type with thrust bearings. The crankshaft is provided with an oil gallery, through which engine oil i s fed t o the crankpin portion, and lubricate it.
The piston is made of aluminum alloy. Three rings are installed in grooves in the piston. The top ring is a keystone type, which can stand against heavy loads, and the barrel face on the ring fits well to the cylinder wall. The second ring is an undercut type, which effectively prevents the oil from being carried up. The oil ring has chamfered contact faces and anexpander ring, which increase the pressure of the oil ring against the cylinder wall.
| Cylinder block | ||
| Compression ratio: | 23.0:1 | |
| Cylinder bore: | 67.0 mm (2.64 in) | |
| Piston stroke: | 68.0 mm (2.68 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
The cross-flow type intake and exhaust ports in the Kubota Z482-B(E) engine have their openings at both sides of the cylinder head. Because overlaps of intake and exhaust ports are smaller than in ports of other types which have openings on one side, the suction air can be protected from being heated and expanded by heated exhaust air.
| Cylinder head | ||
| Valve Arrangement: | OHV, gear drive | |
| Valves: | 4 (2 valves per cylinder) | |
| Valve timing: | INTAKE | Open: 20° B.T.D.C. Close: 45° A.B.D.C. |
| EXHAUST | Open: 50° B.B.D.C. Close: 15° A.T.D.C. | |
| 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) | |
| Rocker arm shaft outer diameter: | 10.473-10.484 mm (0.4123-0.4127 in) | |
| Rocker arm shaft hole inner diameter: | 10.500-10.518 mm (0.4134-0.4141 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 |
| Allowable limit | 2.26 MPa, 23 kgf/cm2, 327 psi |
| Oil system | |
| Recommended engine oil | CD or CE |
| SAE Viscosity Number | SAE 10W-30, 10W-40 |
| Engine oil capacity | Oil pan depth 101 mm (3.98 in): 2.1 L (2.2 US. qt, 1.85 Imp. qt.) Oil pan depth 121 mm (4.76 in): 2.5 L (2.6 US. qt, 2.21 Imp. qt.) |
| Fuel system | |
| Injection timing: | 20-22° B.T.D.C. |
| Fuel injection pressure | 13.73-14.71 MPa (140-150 kgf/cm2, 1991-2133 psi) |
| Cooling system | |
| Coolant capacity: | 2.8 liters (3.0 US.qts, 2.5 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 |
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