Complete specifications for the International Harvester 766, 966, 1066 and 1466 tractors, transcribed from the specifications section of the factory operator's manual. These were IH's "66 series" row-crop tractors, introduced in 1971. One book covers the whole range, from the 291 cu. in. gasoline 766 up to the 436 cu. in. turbocharged 1466, plus All-Wheel Drive and Hi-Clear versions, so most tables below have a column for each tractor.
A note on engine speeds. The diesels are rated at 2600 rpm (the gasoline 766 at 2400 rpm), but the standard PTO speeds of 540 and 1000 rpm arrive at a reduced engine speed of 2300 rpm. That is why the manual prints ground speeds at both the rated speed and 2300 rpm.
Engine
| Specification | 766 Gasoline | 766 Diesel | 966 | 1066 | 1466 |
|---|---|---|---|---|---|
| Make and Model | IH C-291 | IH D-360 | IH D-414 | IH DT-414 | IH DT-436 |
| Cylinders | 6 | ||||
| Bore | 3.750 in. | 3.875 in. | 4.300 in. | 4.300 in. | 4.300 in. |
| Stroke | 4.390 in. | 5.085 in. | 4.750 in. | 4.750 in. | 5.000 in. |
| Displacement | 291 cu. in. | 360 cu. in. | 414 cu. in. | 414 cu. in. | 436 cu. in. |
| Rated Full Load Speed | 2400 rpm | 2600 rpm | 2600 rpm | 2600 rpm | 2600 rpm |
| High Idle (Approx.) | 2640 rpm | 2800 rpm | 2800 rpm | 2800 rpm | 2800 rpm |
| Low Idle (Approx.) | 425 rpm | 700 rpm | 700 rpm | 700 rpm | 700 rpm |
| Engine Speed for Standard PTO Speed | 2300 rpm | ||||
| Firing Order | 1-5-3-6-2-4 | ||||
| Valve Clearance, Intake (Engine Warm) | 0.027 in. | 0.012 in. | 0.020 in. | 0.020 in. | 0.020 in. |
| Valve Clearance, Exhaust (Engine Warm) | 0.027 in. | 0.021 in. | 0.025 in. | 0.025 in. | 0.025 in. |
| Ignition and fuel | |||||
| Distributor Breaker Point Gap | 0.020 in. | — | — | — | — |
| Spark Timing at High Idle | 18° advance | — | — | — | — |
| Spark Plug Gap | 0.023 in. | — | — | — | — |
| Carburetor | IH, 1-3/8 in. | — | — | — | — |
| Injection Pump | — | American Bosch Model 100 | American Bosch Model 100 | American Bosch Model 100 | American Bosch Model 100 |
| Injection Nozzles | — | American Bosch multi-hole | American Bosch multi-hole | American Bosch multi-hole | American Bosch multi-hole |
Capacities
U.S. measure, approximate.
| Specification | 766 Gasoline | 766 Diesel | 966 | 1066 | 1466 |
|---|---|---|---|---|---|
| Belt Pulley Housing (Initial Fill Only) | 2 qt. | ||||
| Cooling System | 20-1/2 qt. | 24 qt. | 26 qt. | 25 qt. | 26 qt. |
| Crankcase with Filter | 9 qt. | 12 qt. | 12 qt. | 20 qt. | 20 qt. |
| Differential Housing (All-Wheel Drive) | — | — | 10 qt. | 10 qt. | 10 qt. |
| Fuel Tank | 37 gal. | 37 gal. | 37 gal. | 42 gal. | 42 gal. |
| Hi-Clear Housing (Each) | 4-1/2 qt.1 | 4-1/2 qt. | 4-1/2 qt. | 4-1/2 qt. | — |
| Transmission, Differential Case and Rear Axle Carrier | 23 gal. | 23 gal. | 24 gal. | 24 gal. | 24 gal. |
PTO Shaft Speeds
Shaft rpm.
| Specification | 766 Gasoline | 766 Diesel | 966 | 1066 | 1466 |
|---|---|---|---|---|---|
| 540 rpm PTO | |||||
| At Rated Engine Speed | 562 | 609 | 609 | 609 | — |
| At High Idle | 618 | 655 | 655 | 655 | — |
| At Low Idle | 99 | 164 | 164 | 164 | — |
| At 2300 rpm Engine Speed | 539 | 539 | 539 | 539 | — |
| 1000 rpm PTO | |||||
| At Rated Engine Speed | 1058 | 1146 | 1146 | 1146 | 1146 |
| At High Idle | 1163 | 1234 | 1234 | 1234 | 1234 |
| At Low Idle | 187 | 308 | 308 | 308 | 308 |
| At 2300 rpm Engine Speed | 1014 | ||||
No 540 rpm PTO is listed for the 1466.
Belt Pulley
| Specification | 766 Gasoline | 766 Diesel and 966 |
|---|---|---|
| At Rated Engine Speed | 1101 rpm | 1089 rpm |
| At High Idle | 1211 rpm | 1172 rpm |
| At Low Idle | 195 rpm | 293 rpm |
| Belt Speed at Rated Engine Speed | 3170 ft./min. | 3136 ft./min. |
| Pulley Diameter | 11 in. | |
| Pulley Face | 7-1/2 in. | |
No belt pulley figures are listed for the 1066 or 1466.
Electrical
| System | 12 volt negative ground (all models) |
|---|---|
| Battery, 766 Gasoline | One 12 volt, 45 amp. hr. |
| Battery, 766 Diesel and 966 | Two 6 volt, 145 amp. hr. |
| Battery, 1066 and 1466 | Two 6 volt, 172 amp. hr. |
| Alternator-Generator, Delco Remy | 72 amp. with cab; 37 amp. without cab |
| Cranking Motor | Delco Remy, positive engagement |
| Light Switch | 4 position |
| Lamps | All glass sealed beam units, 12 volt |
| Fuse (Cartridge, 20 amp.) | SFE-20 or 3AG-20 |
Lamps & Bulbs
| Item | Lamp or Bulb No. | IH Part No. | Assembly No. |
|---|---|---|---|
| Sealed beam lamps | |||
| Headlights | #4411 | 373 662 R91 | 387 730 R91 |
| Floodlights (Deluxe Fenders) | #4406 | 390 756 R91 | 388 946 R91 |
| Rear Light (Combination Rear Light and Taillight) | #4603 | 371 461 R91 | 387 729 R91 |
| Bulbs | |||
| Taillight (Combination) | #1003 | 455 490 | 387 729 R91 |
| Warning Light | #1156 | 9 417 866 | 394 129 R91 |
| Tellites | #257 | 9 412 348 | — |
| Instrument Lights | #1895 | 9 417 863 | — |
| Shift Quadrant Control Light | #1155 | 9 417 865 | 397 946 R1 |
| Cab Dome Light | #1003 | 455 490 | 539 050 R1 |
Clutch, Brakes & Tires
| Specification | 766 Gasoline | 766 Diesel | 966 | 1066 | 1466 |
|---|---|---|---|---|---|
| Clutch, Single-Plate Dyna-Life Dry-Disc, Spring-Loaded2 | 12 in. | 12 in. | 12 in. | 14 in. | 14 in. |
| Foot Brakes, Hydraulic Power Disc Type3 | 8 in. | 8 in. | 8 in. | 8 in. | 11 in. |
| Standard tires (other sizes available) | |||||
| Front | 9.5L-15 F-2 | 9.5L-15 F-2 | 9.5L-15 F-2 | 11L-15 F-2 | 11L-15 F-2 |
| Front, All-Wheel Drive | — | — | 11.2-24 | 11.2-24 | 12.4-24 R-114 |
| Rear | 18.4-34 R1 | 18.4-34 R1 | 18.4-34 R1 | 18.4-38 R1 | 18.4-38 R1 |
| Hi-Clear Front | — | 7.50-20 F-2 | 7.50-20 F-2 | 7.50-20 F-2 | — |
| Hi-Clear Rear | — | 18.4-38 R-2 | 18.4-38 R-2 | 18.4-38 R-2 | — |
General Dimensions
Inches, with three-point hitch and swinging drawbar.
| Specification | 766 Gasoline | 766 Diesel | 966 | 1066 | 1466 |
|---|---|---|---|---|---|
| Wheelbase, Wide Tread | 105 | ||||
| Wheelbase, Tricycle | 101 | 101 | 101 | 101 | — |
| Wheelbase, All-Wheel Drive | — | — | 995 | —5 | —5 |
| Length | 165 | 165 | 165 | 166 | 168 |
| Length, All-Wheel Drive | — | — | 163 | 165 | 167 |
| Width Overall, Minimum | 102 | 102 | 102 | 102 | 98 |
| Height to Steering Wheel | 84 | 84 | 84 | 86 | 86 |
| Height to Top of Cab | 114 | 114 | 114 | 116 | 116 |
| Height to Top of 2-Post ROPS | 110 | 110 | 110 | 110 | 112 |
| Height to Top of 4-Post ROPS | 1126 | 1126 | 1126 | 1156 | 1156 |
| Tread | |||||
| Front, Adjustable Wide Axle | 54 to 78 or 60 to 84 | 54 to 78 or 60 to 84 | 54 to 78 or 60 to 84 | 56 to 80 or 62 to 86 | 56 to 80 or 62 to 86 |
| Front, Tricycle | 8 or 16 | 8 or 16 | 8 or 16 | 8 or 16 | — |
| Front, All-Wheel Drive | — | — | Concave in 67; out 75 | Concave in 67; out 75 | Concave in 67; out 75 |
| Rear, Regular Axles | Concave in 60 to 96; out 62 to 104 | ||||
| Clearance and drawbar | |||||
| Ground Clearance, Front Axle | 20 | 20 | 21 | 21 | 21 |
| Ground Clearance, Front Axle, All-Wheel Drive | — | — | 13 | 13 | 14 |
| Ground Clearance Under Drawbar | 13 | 13 | 14 | 16 | 16 |
| Drawbar Height | 17 | 17 | 17 | 19 | 19 |
| Drawbar Lateral Swing | 19 | ||||
| Drawbar Hitch Hole to End of PTO, Horizontal, 540 | 14 | 14 | 14 | 14 | — |
| Drawbar Hitch Hole to End of PTO, Horizontal, 1000 | 16 | ||||
| Drawbar Hitch to PTO, Vertical, 540 | 7 | 7 | 7 | 7 | — |
| Drawbar Hitch to PTO, Vertical, 1000 | 12 | 12 | 317 | 12 | 12 |
| PTO Shaft Above Ground, 540 | 24 | 24 | 26 | 26 | — |
| PTO Shaft Above Ground, 1000 | 29 | 29 | 31 | 31 | 31 |
| Minimum turning radius, brake applied | |||||
| Wide Axle | 11.4 ft. | 11.4 ft. | 11 ft. | 11.4 ft. | 11.5 ft. |
| All-Wheel Drive | — | — | 17 ft. | 17 ft. | 17 ft. |
Hi-Clear Dimensions
Inches. The 766 Gasoline and 1466 were not listed in Hi-Clear form.
| Dimension | 766 Diesel Hi-Clear | 966 Hi-Clear | 1066 Hi-Clear |
|---|---|---|---|
| Wheelbase | 107 | 106 | 106 |
| Length | 167 | 169 | 169 |
| Width, Minimum | 98 | ||
| Height to Steering Wheel | 97 | ||
| Height to Top of Cab | 129 | 129 | 131 |
| Height to Top of 2-Post ROPS | 125 | ||
| Height to Top of 4-Post ROPS | 123 | 125 | 125 |
| Front Tread | 64 to 84 | ||
| Rear Tread | Concave in 76 to 93; out 82 to 96 | ||
| Ground Clearance, Front Axle | 36 | ||
| Ground Clearance, Drawbar | 26 | 27 | 27 |
| Drawbar Height | 30 | ||
| Drawbar Hitch Hole to End of PTO, Horizontal, 5408 | 2 | 2-1/8 | 2-1/8 |
| Drawbar Hitch Hole to End of PTO, Horizontal, 10008 | 4 | 4-1/8 | 4-1/8 |
| Drawbar Hitch to PTO, Vertical8 | 540: 7; 1000: 12 | ||
| PTO Shaft Above Ground8 | 540: 37; 1000: 42 | ||
| Minimum Turning Radius | 13 ft. | ||
Shipping Weights
Approximate.9
| Specification | 766 Gasoline | 766 Diesel | 966 | 1066 | 1466 |
|---|---|---|---|---|---|
| Tractor | 9,760 lbs. | 10,300 lbs. | 10,730 lbs. | 11,620 lbs. | 11,810 lbs. |
| Hi-Clear | — | 12,200 lbs.10 | 11,610 lbs. | 11,790 lbs. | — |
Ground Speeds
Miles per hour, with no allowance for tire slippage. "Direct" and "T.A." are the Torque Amplifier ranges.
766 and 966 (18.4-34 R-1 tires)
| Gear | Rated, Forward Low | Rated, Forward High | Rated, Reverse | 2300 rpm Gas, Low | 2300 rpm Gas, High | 2300 rpm Diesel, Low | 2300 rpm Diesel, High |
|---|---|---|---|---|---|---|---|
| 1st Direct | 1.8 | 6.4 | 3.2 | 1.8 | 6.2 | 1.6 | 5.7 |
| 1st T.A. | 1.4 | 5.0 | 2.5 | 1.4 | 4.8 | 1.3 | 4.4 |
| 2nd Direct | 2.5 | 8.6 | 4.2 | 2.3 | 8.2 | 2.2 | 7.6 |
| 2nd T.A. | 1.9 | 6.7 | 3.3 | 1.8 | 6.4 | 1.7 | 5.9 |
| 3rd Direct | 4.3 | 14.9 | 7.3 | 4.1 | 14.3 | 3.8 | 13.2 |
| 3rd T.A. | 3.3 | 11.6 | 5.7 | 3.2 | 11.1 | 2.9 | 10.3 |
| 4th Direct | 5.7 | 19.8 | 9.8 | 5.4 | 19.0 | 5.0 | 17.6 |
| 4th T.A. | 4.4 | 15.5 | 7.6 | 4.2 | 14.8 | 3.9 | 13.7 |
Rated engine speed is 2400 rpm for the gasoline 766 and 2600 rpm for the diesels.
1066 and 1466 (18.4-38 R-1 tires)
| Gear | 2600 rpm, Forward Low | 2600 rpm, Forward High | 2600 rpm, Reverse | 2300 rpm, Low | 2300 rpm, High |
|---|---|---|---|---|---|
| 1st Direct | 2.1 | 7.2 | 3.5 | 1.8 | 6.4 |
| 1st T.A. | 1.6 | 5.6 | 2.8 | 1.4 | 5.0 |
| 2nd Direct | 2.7 | 9.6 | 4.7 | 2.4 | 8.5 |
| 2nd T.A. | 2.1 | 7.5 | 3.7 | 1.9 | 6.6 |
| 3rd Direct | 4.8 | 16.6 | 8.2 | 4.2 | 14.7 |
| 3rd T.A. | 3.7 | 13.0 | 6.4 | 3.3 | 11.5 |
| 4th Direct | 6.4 | 12.211 | 10.9 | 5.6 | 19.6 |
| 4th T.A. | 5.0 | 17.3 | 8.5 | 4.4 | 15.3 |
Hi-Clear 766, 966 and 1066 (18.4-38 R-2 tires)
| Gear | 2600 rpm, Forward Low | 2600 rpm, Forward High | 2600 rpm, Reverse | 2300 rpm, Low | 2300 rpm, High |
|---|---|---|---|---|---|
| 1st Direct | 1.7 | 5.8 | 2.8 | 1.8 | 6.2 |
| 1st T.A. | 1.3 | 4.5 | 2.2 | 1.4 | 4.8 |
| 2nd Direct | 2.2 | 7.7 | 3.8 | 2.4 | 8.3 |
| 2nd T.A. | 1.7 | 6.0 | 2.9 | 1.8 | 6.4 |
| 3rd Direct | 3.8 | 13.3 | 6.5 | 4.1 | 14.3 |
| 3rd T.A. | 3.0 | 10.4 | 5.1 | 3.2 | 11.2 |
| 4th Direct | 5.1 | 17.7 | 8.7 | 5.5 | 19.1 |
| 4th T.A. | 4.0 | 13.8 | 6.8 | 4.3 | 15.0 |
As printed, the Hi-Clear speeds at 2300 rpm are higher than at 2600 rpm.12
Notes:
1 The manual prints this figure across the 766 Gasoline to 1066 columns. The 766 Gasoline is not otherwise listed in Hi-Clear form.
2 Maintain 9/16 in. free pedal travel.
3 Operated individually or interlocked.
4 As printed. The note on page 108 of the manual describes the 1466 All-Wheel Drive tire as 12.4-24 R1, so "R-11" is likely a misprint.
5 The manual prints 99 in. in the 966 column with no dividers to the 1066 and 1466 columns. It may apply to all three All-Wheel Drive tractors. TODO: confirm.
6 No divider is printed in this row. The split between 112 and 115 in. is read from the position of the figures. TODO: confirm.
7 As printed. Every other tractor shows 12 in. here, so "31" is likely a misprint.
8 The manual notes that Farmall Hi-Clear tractors have standard PTO shafts but do not conform fully to ASAE standards, because of their high-clearance construction.
9 With standard tires, three-point hitch, wide front axle, swinging drawbar, independent PTO, Torque Amplifier, one auxiliary valve, deluxe seat, deluxe fenders and liquid in the cooling system, without fuel, weights or ballast. All-Wheel Drive with 11.2-24 R1 tires adds about 900 lbs. (966) or 700 lbs. (1066); the 1466 All-Wheel Drive with 12.4-24 R1 tires adds about 1,100 lbs.
10 As printed. The 766 Diesel Hi-Clear is listed heavier than the 966 and 1066 Hi-Clear.
11 As printed. It is lower than the 4th T.A. high-range figure of 17.3 mph. In every other row Direct is about 1.28 times T.A., which points to roughly 22.2 mph. TODO: confirm against the scan.
12 Analytical: on the other tables, speeds at 2300 rpm are lower than at the rated speed. The Hi-Clear column headings may be transposed in the manual. Reproduced as printed. TODO: confirm.
All specifications transcribed from the specifications section of the International 766, 966, 1066 and 1466 Tractors operator's manual, originally published by International Harvester Company. The manual states that specifications are subject to change without notice; verify against your tractor's serial number before ordering parts or setting clearances.
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