The Kubota Z851 is a 867 cc (52.9 cu·in) natural aspirated two-cylinders four-stroke liquid-cooled internal combustion vertical diesel engine, manufactured by Kubota Corporation for general-purpose applications.
The cylinder bore and piston stroke are 76.0 mm (2.99 in) and 82.0 mm (3.23 in), respectively.
This engine produced 18.2 PS (13.4 kW; 18.0 HP) at 3,000 rpm of horsepower.
The Kubota Z851 features:
- Fuel injection pump
- Centrifugal ball mechanical governor
- Forced lubrication by pump
- Liquid cooling system
- Electric starter
- Charging alternator
General information
Engine Specifications | |
Engine model | Z851 |
Engine type | 4-stroke, vertical, two-cylinders |
Displacement | 867 cm3, (52.9 cu·in) |
Max. horsepower | 18.2 PS (13.4 kW; 18.0 HP) at 3,000 rpm |
Max. torque | – |
Cooling system | Liquid-cooled |
Lubricating system | Forced lubrication by pump |
Combustion chamber | – |
Fuel system | Fuel injection pump |
Injection type | Indirect injection |
Fuel used | Diesel fuel No.2-D |
Starting system | Electric starter |
Governor | Centrifugal ball mechanical governor |
PTO shaft rotation | Counterclockwise (from PTO shaft side) |
Dimensions (L x W X H) | – |
Dry weight | – |
Cylinder Block and Head
Cylinder block | |
Compression ratio: | – |
Cylinder bore: | 82.0 mm (3.23 in) |
Piston stroke: | 82.0 mm (3.23 in) |
Cylinder internal diameter (standard): | 82.000-82.022 mm (3.2283-3.2292 in) |
Piston skirt diameter (standard): | – |
Number of piston rings (compression / oil): | 2/1 |
Piston pin diameter: | 23.002-23.011 mm (0.9056-0.9059 in) |
Side clearance (Second): | 0.090-0.120 mm (0.0040-0.0050 in) |
Side clearance (Oil): | 0.020-0.050 mm (0.0008-0.0020 in) |
Ring end gap (Top): | 0.300-0.450 mm (0.0118-0.0177 in) |
Ring end gap (Second): | 0.300-0.450 mm (0.0118-0.0177 in) |
Ring end gap (Oil): | 0.250-0.400 mm (0.0098-0.0157 in) |
Number of main bearings: | 3 |
Crankshaft main journal diameter: | 51.921-51.940 mm (2.0441-2.0449 in) |
Crankpin journal diameter: | 43.959-43.975 mm (1.7307-1.7313 in) |
Cylinder head | |
Valves: | 2, (4 valves in total) |
Valve seat width (INTAKE): | 2.100 mm (0.080 in) |
Valve seat width (EXHAUST): | 2.100 mm (0.080 in) |
Value seat angle (INTAKE): | 45° |
Value seat angle (EXHAUST): | 45° |
Valveface angle (INTAKE): | 45° |
Valveface angle (EXHAUST): | 45° |
Valve steam diameter (INTAKE): | 7.960-7.975 mm (0.3134-0.3140 in) |
Valve steam diameter (EXHAUST): | 7.960-7.975 mm (0.3134-0.3140 in) |
Valve spring free length (INTAKE): | 42.0 mm (1.6535 in) |
Valve spring free length (EXHAUST): | 42.0 mm (1.6535 in) |
Camshaft journal diameter : | 39.935-39.950 mm (1.5722-1.5728 in) |
Tightening torque
Tightening torque specs | |
Cylinder head screw: | 75.0-78.0 Nm (7.65-7.80 kgf·m, 55.3-58.0 lb·ft) |
Connecting rod screw: | 37.0-41.0 Nm (3.8-4.2 kgf·m; 27.3-30.3 lb·ft) |
Flywheel screw: | 54.0-58.0 Nm (5.5-5.9 kgf·m; 39.9-42.8 lb·ft) |
Idle gear shaft screws: | 32.4-37.3 Nm (3.3-3.8 kgf·m; 23.9-27.5 lb·ft) |
Bearing case cover mounting screw: | 30.0-34.0 Nm (3.0-3.4 kgf·m; 22.0-25.0 lb·ft) |
Service Data
Engine | |
Maximum speed: | 2,950 rpm |
Idle speed: | 600-650 rpm |
Valve clearance | |
Intake valve clearance: | 0.18-0.22 mm (0.0071-0.0087 in) |
Exhaust valve clearance: | 0.18-0.22 mm (0.0071-0.0087 in) |
Oil system | |
Lubrication system: | Forced lubrication |
Oil type: | DS or DM |
Recommended oil: | SAE 80 |
Oil capacity: | 3.8 liters (4.02 US.qts, 3.34 Imp. qts) |
Fuel system | |
Injection timing: | 25° B.T.D.C. |
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 |
Coolant capacity: | 5.3 liters (5.6 US.qts, 4.7 Imp. qts) |
Electrical system | |
Battery: | 12V, 65AH or equivalent |
Applications
Manufacturer or Brand | Models |
Tractors | |
Kubota | L1801 |
We try to use official documentation and verify the published data, but errors may occur. In addition, specifications of machinery and equipment may vary depending on markets and modifications. We do not recommend the use of this data for spare parts or repairs. Use official service manuals or parts catalogs for your product.
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