Kubota Z602

Kubota Z602The Kubota Z602 is a 0.6 L (599 cc, 36.5 cu·in) straight-two, water-cooled naturally aspirated vertical diesel engine manufactured by Kubota.

The Kubota Z602 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. It has a 72.0 mm (2.83 in) cylinder bore and a 73.6 mm (2.9 in) piston stroke. The Z602 diesel engine produced 17 PS (12.5 kW; 16.8 HP) at 3,600 rpm of gross (intermittent) horsepower and 37.8 Nm (3.86 kg·m; 27.9 ft·lb) at 2,600 rpm of torque.

The breakdown of the engine code is as follows:

  • Z – 2-cylinders
  • 60 – Approximate displacement 600 cc

General information

Engine Specifications
Engine code Z602-E, -E2B, -E3B
Layout Straight-2, vertical diesel engine
Fuel type Diesel fuel No.2-D
Displacement 0.6 L, 599 cm3 (36.5 cu in)
Fuel injection pump Bosch MD type mini fuel injection pump
Fuel nozzle Bosch throttle type
Starting system Electric starting with 12V (1.0 kW) starter
Starting support device Glow plug in combustion chamber
Governor Centrifugal ball mechanical governor
Power adder None
Max. Horsepower 17 PS (12.5 kW; 16.8 HP) at 3,600 rpm
Torque output 37.8 Nm (3.86 kg·m; 27.9 ft·lb) at 2,600 rpm
Firing order 1-2
Dimensions (L x W x H): 384 x 404 x 544 mm (15.1 x 15.9 x 21.4 in)
Weight 57.0 kg (125.7 lbs)

Cylinder block

Cylinder block
Compression ratio: 24.0:1
Cylinder bore: 72.0 mm (2.83 in)
Piston stroke: 73.6 mm (2.9 in)
Number of piston rings (compression / oil): 2 / 1
Cylinder inner diameter: 72.000-72.019 mm (2.8346-2.8354 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 0.200-0.350 mm (0.0079-0.0138 in)
Second 0.350-0.500 mm (0.0138-0.0197 in)
Oil 0.200-0.350 mm (0.0079-0.0138 in)
Piston pin outer diameter 20.002-20.011 mm (0.7875-0.7878 in)
Crankshaft main journal diameter: 43.934-43.950 mm (1.72969-1.73032 in)
Crankpin diameter: 33.959-33.975 mm (1.337-1.3376 in)

Cylinder head

Cylinder head
Valve Arrangement: OHV, gear drive
Valves: 4 (2 valves per cylinder)
Valve timing: INTAKE Open: 20° B.T.D.C.
Close: 45° B.T.D.C.
EXHAUST Open: 50° B.T.D.C.
Close: 15° B.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)
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 36.0-41.0 kgf/cm2 (3.53-4.02 MPa, 512-583 psi)
Oil system
Recommended engine oil CD or CE
SAE Viscosity Number SAE 10W-30, 10W-40
Engine oil capacity 2.5 L (2.6 US. qt, 2.21 Imp. qt.)
Fuel system
Injection timing: 17-21° B.T.D.C. (depending on model)
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, 36Ah or equivalent
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)
Author: Sergei Wers
About: Co-founder and CEO of a multi-brand auto repair shop (engine repair, chassis repair, body repair and painting) for over 15 years. I have been developing internet sites with technical specifications for more than seven years.

ATTENTION! Dear visitors, this site is not a trading platform, an official dealer or a spare parts supplier, so we do not have any price lists or spare parts catalogs. We are an information portal and provide the technical specifications of gasoline and diesel engines.

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.

1 Comment

Leave a Reply

Your email address will not be published.