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Kubota Z602 Engine

General Technical Data

Kubota Z602 Engine Specifications

Engine Model .......... Kubota Z602
Engine Type .......... Vertical, water-cooled, 4-stroke diesel
Number of cylinders .......... Two
Bore, mm (in.) .......... 72.0 (2.83)
Stroke, mm (in.) .......... 73.6 (2.90)
Total displacement, cm3 (cu. in.) .......... 599 (36.6)
Gross power, kw (hp) .......... 12.5 (16.8)
Net power, kw (hp) .......... 11.6 (15.5)
Maximum speed, rpm .......... 3800
Idling speed, rpm .......... 900-1000
Combustion Chamber .......... Spherical type (E-TVCS)
Direction of rotation .......... Counter-clockwise
Compression ratio .......... 24:1
Firing order .......... 1-2

Fuel System

Fuel injection pump .......... Bosch MD type mini pump
Injection nozzle .......... Bosch "Throttle" type
Injection timing, deg (rad) .......... 20 (0.35) before T.D.C.
Injection pressure, MPa (psi) .......... 13.73 (1991)
Governor .......... All speed mechanical governor

Lubricating System

Lubricating system .......... Forced lubrication by trochoid pump
Oil pressure indicating .......... Electrical type switch
Oil filter .......... Full flow paper filter (cartridge type)

Electrical System

Starting system .......... Electric starting with starter
Starting Motor .......... 12V, 1.0 kW
Starting support device .......... By glow plug in combustion chamber
Battery .......... 12V, 36 AH
Charging Alternator .......... 12V, 480W

Dimensions

Length, mm (in.) .......... 385.0 (15.2)
Width, mm (in.) .......... 421.0 (16.6)
Height, mm (in.) .......... 544.0 (21.4)
Dry weight, kg (lbs.) .......... 60.0 (132)

Kubota Z602 Maintenance Data

Fuel type .......... Diesel fuel No. 2-D
Engine oil type .......... SAE 10W-30/15W-40
Engine oil capacity, L (qts) .......... 2.5 (2.6)
Coolant capacity, L (qts) .......... 2.8 (3.0)
Oil filter change interval .......... Every 200 hours
Oil change interval .......... Every 200 hours
Fuel filter change interval .......... Every 400 hours

Kubota Z602 Service Specifications

Cylinder Block

Cylinder Liner I.D. .......... 72.000-72.019 mm (2.8347-2.8353 in.)
Cylinder Liner (Oversize 0.25 mm) I.D. .......... 72.250-72.269 mm (2.8445-2.8452 in.)
Cam Height (Intake and Exhaust) .......... 26.88 mm (1.058 in.)
Camshaft Journal to Cylinder Block Bore, Oil Clearance .......... 0.050-0.091 mm (0.0020-0.0035 in.)
Piston Pin Bore I.D. .......... 20.000-20.013 mm (0.78741-0.78791 in.)
Piston Pin to Small End Bushing, Oil Clearance .......... 0.014-0.038 mm (0.00056-0.0014 in.)
Piston Pin O.D. .......... 20.002-20.011 mm (0.78748-0.78783 in.)
Crankshaft Journal to Crankshaft Bearing 1, Oil Clearance .......... 0.0340-0.106 mm (0.00134-0.00417 in.)
Crankshaft Journal O.D. .......... 43.934-43.950 mm (1.7297-1.7303 in.)
Crankshaft Bearing 1 I.D. .......... 43.984-44.040 mm (1.7317-1.7338 in.)
Crankshaft Journal to Crankshaft Bearing 2 (Flywheel Side), Clearance ........ 0.028-0.059 mm (0.0011-0.002 in)
Crankshaft Journal O.D. .......... 43.934-43.950 mm (1.7297-1.7303 in.)
Crankshaft Bearing 2 I.D. .......... 43.978-43.993 mm (1.7315-1.7320 in.)
Crankshaft Journal to Crankshaft Bearing 3 (Intermediate), Clearance ........ 0.028-0.059 mm (0.0011-0.002 in)
Crankshaft Journal O.D. .......... 43.934-43.950 mm (1.7297-1.7303 in.)
Crankshaft Bearing 3 I.D. .......... 43.978-43.993 mm (1.7315-1.7320 in.)

Cylinder Head

Valve Clearance (Cold) .......... 0.145-0.185 mm (0.00571-0.00728 in.)
Compression Pressure .......... 3.53-4.02 MPa (512-583 psi)
Top Clearance .......... 0.50-0.70 mm (0.020-0.027 in.)
Cylinder Head Surface, Flatness .......... 0.05 mm (0.002 in.)
Valve Recessing (Intake and Exhaust) .......... 0.10-0.10 mm (0.0039-0.0039 in.)
Valve Stem to Valve Guide (Intake and Exhaust), Clearance .......... 0.030-0.057 mm (0.0012-0.0022 in.)
Valve Stem O.D. .......... 5.968-5.980 mm (0.2350-0.2354 in.)
Valve Guide I.D. .......... 6.010-6.025 mm (0.2367-0.2372 in.)
Rocker Arm Shaft to Rocker Arm, Oil Clearance .......... 0.016-0.045 mm (0.00063-0.0017 in.)
Rocker Arm Shaft O.D. .......... 10.473-10.484 mm (0.41233-0.41275 in.)
Rocker Arm I.D. .......... 10.500-10.518 mm (0.41339-0.41409 in.)
Push Rod Alignment – 0.25 mm (0.0098 in.)

Idle Gear

Idle Gear Shaft to Idle Gear Bushing, Oil Clearance .......... 0.020-0.084 mm (0.00079-0.0033 in.)
Idle Gear Shaft O.D. .......... 19.967-19.980 mm (0.78611-0.78661 in.)
Idle Gear Bushing I.D. .......... 20.000-20.051 mm (0.78740-0.78940 in.)

Lubricating System

Engine Oil Pressure At Idle Speed .......... More than 49 kPa (7.1 psi)
Engine Oil Pressure At Rated Speed .......... 197-441 kPa (28.5-64.0 psi)
Inner Rotor to Outer Rotor, Clearance .......... 0.030-0.14 mm (0.0012-0.0055 in.)
Outer Rotor to Pump Body, Clearance .......... 0.070-0.15 mm (0.0028-0.0059 in.)
Inner Rotor to Cover, Clearance .......... 0.0750-0.135 mm (0.00296-0.00531 in.)

Tightening Torque Specs

Cylinder head cover screw (M6 x 1), Nm (lb.-ft.) .......... 9.81-11.2 (7.24-8.31)
Cylinder head screw (M8 x 1.25), Nm (lb.-ft.) .......... 38-42 (28-31)
Flywheel screw (M10 x 1.25), Nm (lb.-ft.) .......... 54-58 (40-43)
Rocker arm bracket nut (M6 x 1), Nm (lb.-ft.) .......... 9.81-11.2 (7.24-8.31)
Fan drive pulley screw (M12 x 1.5), Nm (lb.-ft.) .......... 118-127 (86.8-94.0)
Idle gear shaft mounting screw (M6 x 1), Nm (lb.-ft.) .......... 9.81-11.2 (7.24-8.31)
Oil pump mounting screw (M8 x 1.25), Nm (lb.-ft.) .......... 17.7-21.5 (13.1-15.9)
Connecting rod screw (M7 x 0.75), Nm (lb.-ft.) .......... 27-30 (20-22)

KUBOTA TRACTORS TROUBLESHOOTING
L235	L2501	L2550	L275	L3110
L3301	L35	L3710	L3901	L4310
L5030	M4700	M5700	M6040	M6800
M8200	M8540	M9000	MX5100	MX5200