International Harvester

International Harvester 666

The International Harvester 666 is a row-crop tractor produced from 1972 to 1976 by International Harvester in Rock Island, Illinois, USA. It was available with either a 5.1L 6-cylinder diesel or a 4.8L 6-cylinder gasoline engine, both producing 75 hp gross. The tractor featured multiple transmission options including 5-speed sliding gear, hydrostatic, and a 10-speed two-speed power shift with torque amplifier. It had a power steering system, dry disc brakes, and an open operator station with optional ROPS, canopy, or cab with air-conditioning. The 666 had a wheelbase of 103 inches and weighed between 6780 and 7420 pounds depending on configuration. It was equipped with an IH Fast Hitch and an independent 540 rpm rear PTO. A torque amplifier was optional, and the hydrostatic version was renamed the 70 Hydro in 1973. A total of 9,367 units were built.

Power75 hp

Founded1972 - 1976

Model666

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Technical Specifications

Detailed specifications and technical data for International Harvester 666

Power

PTO (tested)	69.61 hp (51.9 kW)
PTO (claimed)	65 hp (gear) (48.5 kW), 69 hp (hydro) (51.5 kW)
Engine (gross)	75 hp (55.9 kW)
Drawbar (tested)	58.01 hp (43.3 kW)
Drawbar (claimed)	57 hp (gear) (42.5 kW), 54 hp (hydro) (40.3 kW)

Engine

Diesel type	diesel
Gasoline type	gasoline
Diesel cooling	liquid-cooled
Engine options	International Harvester 5.1L 6-cyl diesel, International Harvester 4.8L 6-cyl gasoline
Diesel cylinders	6-cylinder
Diesel rated RPM	2000
Gasoline cooling	liquid-cooled
Diesel air cleaner	dual stage dry
Diesel bore/stroke	3.875x4.410 inches (98 x 112 mm)
Diesel compression	17:1
Diesel fuel system	direct injection
Gasoline cylinders	6-cylinder
Gasoline rated RPM	2000
Diesel displacement	312 ci (5.1 L)
Diesel engine model	International Harvester D312
Diesel power (gross)	75 hp (55.9 kW)
Diesel starter volts	12
Gasoline air cleaner	dual stage dry
Gasoline bore/stroke	3.75x4.39 inches (95 x 112 mm)
Gasoline compression	7.5:1
Gasoline displacement	291 ci (4.8 L)
Gasoline engine model	International Harvester C291
Gasoline power (gross)	75 hp (55.9 kW)
Gasoline starter volts	12
Diesel coolant capacity	21 qts (19.9 L)
Gasoline coolant capacity	21 qts (19.9 L)
Fuel tank capacity (diesel)	31 gal (117.3 L)
Fuel tank capacity (gasoline)	33 gal (124.9 L)

Electrical

Battery volts	12
Charging system	alternator

Hydraulics

Type	open center
Pump flow	12 gpm (45.4 lpm)

Mechanical

Drive	Two-wheel drive
Brakes	Dry disc brakes
Steering	Power steering
Operator station	Open operator station. Two-post ROPS or canopy optional. Cab available with air-conditioning.

Production

Type	Row-Crop tractor
Notes	Torque amplifier was an option. In 1973, the hydrostatic version of the 666 was renamed the 70 Hydro.
Built in	Rock Island, Illinois, USA
Total built	9,367
Original price	$11,875
Years produced	1972 - 1976

Transmission

Clutch	dry disc
Transmission options	5-speed, hydrostatic, 10-speed two-speed power shift
Hydrostatic transmission	infinite forward and reverse
Sliding gear transmission	5 forward and 1 reverse
Torque-Amplifier transmission	two-speed power shift, 10 forward and 2 reverse

Tractor hitch

Type	IH Fast Hitch
Rear Type	II

Serial Numbers

1972	7500
1973	8200
1974	11585
1975	13131
1976	15739
Location	Clutch housing, right side

Dimensions & Tires

Width	87 inches (220 cm)
Length	161 inches (408 cm)
Rear tire	15.5-38
Wheelbase	103 inches (261 cm)
Front tire	7.50-16
Rear tread	50 to 96 inches (127 to 243 cm)
Front tread	50 to 74 inches (127 to 187 cm), 56 to 80 inches (142 to 203 cm)
Shipping weight	6780 lbs (gas gear) (3075 kg), 7420 lbs (diesel hydro) (3365 kg)
Clearance (drawbar)	14 inches (35 cm)
Clearance (front axle)	21 inches (53 cm)
Height (steering wheel)	77 inches (195 cm)