| Manufacturer | International Harvester |
| Price | 11,875(USD) |
| Model | 666 |
| Equipment Type | - |
| Factory |
NEBRASKA TRACTOR TEST 1151 2
| Description | 312 diesel Torque Amplifier 2WD November 3 - 14, 1973 Link: Nebraska Tractor Test 1151 file PTO performance Drawbar performance Gear 3-Direct used for power test Gear 2-TA used for pull test |
| Power at rated engine speed | 66.29hp / 49.4kW |
| Fuel use | 4.6gal/hour / 17.4l/hour |
| Max power | 58.01hp / 43.3kW |
| Max pull | 8,012lbs / 3634kg |
NEBRASKA TRACTOR TEST 1152 2
| Description | Gasoline Torque Amplifier 2WD November 5 - December 3, 1973 Link: Nebraska Tractor Test 1152 file PTO performance Drawbar performance Gear 3-Direct used for power test Gear 2-TA used for pull test |
| Power at rated engine speed | 66.30hp / 49.4kW |
| Fuel use | 5.7gal/hour / 21.6l/hour |
| Max power | 57.29hp / 42.7kW |
| Max pull | 7,981lbs / 3620kg |
NEBRASKA TRACTOR TEST 1154 2
| Description | Gasoline hydrostatic 2WD November 14 - December 3, 1973 Link: Nebraska Tractor Test 1154 file PTO performance Drawbar performance |
| Power at rated engine speed | 69.61hp / 51.9kW |
| Fuel use | 7.7gal/hour / 29.1l/hour |
| Power at rated PTO speed | 64.10hp / 47.8kW |
| Max power | 53.86hp / 40.2kW |
| Max pull | 8,427lbs / 3822kg |
NEBRASKA TRACTOR TEST 1155 2
| Description | Diesel hydrostatic 2WD November 14 - December 3, 1973 Link: Nebraska Tractor Test 1155 file PTO performance Drawbar performance |
| Power at rated engine speed | 69.51hp / 51.8kW |
| Fuel use | 5.6gal/hour / 21.2l/hour |
| Power at rated PTO speed | 65.41hp / 48.8kW |
| Max power | 53.10hp / 39.6kW |
| Max pull | 8,310lbs / 3769kg |
INTERNATIONAL HARVESTER 666 POWER
| Drawbar (tested) | 58.01hp / 43.3kW |
| PTO (tested) | 69.61hp / 51.9kW |
ENGINES OVERVIEW
The International Harvester 666 tractor is powered by either a 5.1L 6-cylinder diesel or a 4.8L 6-cylinder gasoline engine, providing flexibility depending on fuel availability and operating conditions. The diesel variant offers higher torque and better fuel efficiency, making it ideal for heavy-duty applications, while the gasoline engine may provide easier starting in colder climates. However, the diesel engine's complexity and higher initial cost can be drawbacks for some users, especially in less demanding farming scenarios.
| Description | International Harvester 5.1L 6-cyl diesel/International Harvester 4.8L 6-cyl gasoline |
ENGINE DETAIL 1
The International Harvester 666 features a robust D312 diesel engine with a displacement of 5.1L, offering a balance of torque and fuel efficiency at a rated RPM of 2000. With a compression ratio of 17:1, it performs well in demanding applications, but this higher compression may require quality diesel to prevent knocking. Additionally, the dual-stage dry air cleaner enhances engine longevity by effectively filtering out particulates, making it suitable for rugged or dusty terrains.
| Description | International Harvester D312 diesel 6-cylinder liquid-cooled |
| Displacement | 312ci / 5.1L |
| Bore/Stroke | 3.875x4.410inches / 98x 112mm |
| Air cleaner | dual stage dry |
| Compression | 17:1 |
| Rated RPM | 2000 |
| Starter volts | 12 |
ENGINE DETAIL 2
The International Harvester 666 features a robust 6-cylinder, 291ci gasoline engine, delivering a reliable performance at a rated RPM of 2000, making it suitable for moderate agricultural tasks. Its 7.5:1 compression ratio and dual-stage dry air cleaner enhance efficiency and durability, although lower compression may limit power output compared to modern engines. The 12V starter provides ample starting power, but consider its fuel consumption and maintenance when evaluating for heavy-duty operations.
| Description | International Harvester C291 gasoline 6-cylinder liquid-cooled |
| Displacement | 291ci / 4.8L |
| Bore/Stroke | 3.75x4.39inches / 95x 112mm |
| Air cleaner | dual stage dry |
| Compression | 7.5:1 |
| Rated RPM | 2000 |
| Starter volts | 12 |
INTERNATIONAL HARVESTER 666 ENGINES
The International Harvester 666 offers versatility with two engine options: a robust 5.1L 6-cylinder diesel that provides better torque and fuel efficiency, ideal for heavy-duty applications, and a 4.8L 6-cylinder gasoline variant, which offers smoother operation and easier starting in colder climates. The use of a 6-cylinder configuration ensures balanced power delivery and improved longevity, but potential challenges include higher maintenance costs for the diesel model due to complex fuel systems. Ultimately, the choice between diesel and gasoline depends on the specific farming scenarios, such as load requirements and operational conditions.
| Description | International Harvester 5.1L 6-cyl diesel/International Harvester 4.8L 6-cyl gasoline |
TRANSMISSIONS OVERVIEW
The International Harvester 666 tractor features a 5-speed hydrostatic transmission coupled with a 10-speed partial power shift, enabling smooth transitions and enhanced control over various terrain and workload conditions. The hydrostatic drive allows for infinite speed adjustments, ideal for precise applications like tilling and planting, while the power shift enhances productivity during transport operations. However, users may face challenges in maintenance complexity and potential repair costs associated with the power-shift mechanism, making operator training essential for optimal performance.
| Description | 5-speed hydrostatic 10-speed partial power shift |
TRANSMISSION 1
The International Harvester 666 tractor features a sliding gear transmission, enabling straightforward power management between the five forward and one reverse gears. This transmission type offers simplicity in operation, making it suitable for various agricultural tasks but may require more driver skill to manage gear engagement smoothly. Users should be aware that while it provides reliability, the lack of synchronized shifting can lead to increased wear in demanding operations or when frequently changing speeds.
| Transmission | sliding gear |
| Gears | 5 forward and 1 reverse |
TRANSMISSION 2
The International Harvester 666 features a hydrostatic transmission providing smooth and infinitely adjustable speed control in both forward and reverse, enhancing maneuverability in confined spaces. This design excels in applications requiring precision, such as landscaping or towing, where rapid direction changes are necessary. However, hydrostatic systems may require more maintenance and could be less efficient in heavy-duty applications compared to traditional gear transmissions.
| Type | hydrostatic |
| Gears | infinite forward and reverse |
TRANSMISSION 3
The International Harvester 666 tractor features a partial power shift transmission with 10 forward and 2 reverse gears, allowing for smooth gear transitions and efficient torque management during operation. The incorporation of a torque amplifier enhances pulling power, particularly in challenging field conditions, though it may increase complexity in maintenance. The dry disc clutch provides durability but can lead to increased wear if not properly managed, impacting long-term reliability.
| Transmission | Torque-Amplifier |
| Type | partial power shift |
| Gears | 10 forward and 2 reverse |
| Clutch | dry disc |
MECHANICAL
The International Harvester 666 features a 4x2 2WD chassis, which offers simplicity and reduced weight for light to moderate field tasks but may limit traction on uneven terrain. The hydrostatic power steering enhances operator comfort and maneuverability, although it may not be as robust as mechanical systems in heavy-duty applications. Its 5-speed hydrostatic transmission allows for smooth speed adjustments, while the optional 10-speed partial power shift provides flexibility for various operational scenarios, making it suitable for diverse agricultural tasks.
| Chassis | 4x2 2WD |
| Steering | hydrostatic power |
| Brakes | dry disc |
| Cab | Open operator station. Two-post ROPS or canpoy optional |
| Transmissions | 5-speed hydrostatic 10-speed partial power shift |
TRACTOR HITCH
| Rear Type | II |
| Type | IH Fast Hitch |
POWER TAKE-OFF (PTO)
| Rear PTO | independent |
| Rear RPM | 540 |
INTERNATIONAL HARVESTER 666 TIRES
The International Harvester 666 features a lightweight Ag front tire size of 7.50-16, enhancing maneuverability in tight spaces, while the robust Ag rear tires at 15.5-38 provide excellent traction and stability for heavier tasks such as tilling and plowing. A key advantage of this tire combination is the effective weight distribution, which can improve soil conservation and reduce compaction. However, the tractor's performance may be hindered on overly soft or muddy terrain due to the front tire's narrower width, necessitating careful operation in such conditions.
| Ag front | 7.50-16 |
| Ag rear | 15.5-38 |
DIMENSIONS
| Wheelbase | 103inches / 261cm |
| Weight | 7053lbs / 3199kg |
DIMENSIONS & TIRES
The International Harvester 666 tractor features a 103-inch wheelbase that contributes to stable maneuverability on uneven terrain, making it suitable for various agricultural applications. Weighing 7,053 lbs, it offers a substantial footprint for traction and can efficiently handle heavier loads, though this weight may limit mobility in softer ground conditions. Its tire sizes—7.50-16 at the front and 15.5-38 at the rear—provide a good balance of flotation and ground penetration, enhancing performance in both plowing and cultivating tasks.
| Wheelbase | 103inches / 261cm |
| Weight | 7053lbs / 3199kg |
| Front tire | 7.50-16 |
| Rear tire | 15.5-38 |
666 SERIAL NUMBERS
| Location | Clutch housing, right side |
| 1972 | 7500 |
| 1973 | 8200 |
| 1974 | 11585 |
| 1975 | 13131 |
| 1976 | 15739 |