International Harvester 686

The International Harvester 686 is a tractor produced by International Harvester. It is equipped with a 291 ci 4.8 L engine. The listed engine power is 66.36 hp 49.5 kW. Transmission: Torque Amplifier. Operating weight: 7770 lbs 3524 kg.

Engine Power

66.36 hp 49.5 kW

Fuel & Capacities

31 gal 117.3 L

Transmission

Torque Amplifier

Operating Weight

7770 lbs 3524 kg

Overview

	1976 - 1980

Production
Manufacturer	International Harvester
Total built	6,000
Original price was $14,700 in 1980
The International Harvester 686 is nearly identical to the IH 666, it was simply renamed when the 86 series arrived in 1976. One major change did occur in 1979, when the 310 diesel replaced the 312.

International Harvester 686 Transmission
10-speed two-speed power shift
Transmission details ...

International Harvester 686 Power
Drawbar (tested)	58.01 hp 43.3 kW
PTO (tested)	66.36 hp 49.5 kW
Performance test details ...

Mechanical
Two-wheel drive
Power steering
Disc brakes
Two-post fixed ROPS.

Capacity
Fuel	31 gal 117.3 L
Hydraulic system	16 gal 60.6 L

Hydraulics
Type	open center
Capacity	16 gal 60.6 L
Total flow	12 gpm 45.4 lpm

Tractor hitch
Rear Type	II

Power Take-off (PTO)
Rear PTO	independent
Rear PTO Type	540 (1.375)

Dimensions & Tires
Wheelbase	103 inches 261 cm
Weight	7770 lbs 3524 kg
Front tire	7.50-16
Rear tire	15.5-38
Full dimensions and tires ...

References

1979 Buyer's Guide published by International Harvester
Agricultural Equipment Reference Catalog published in 1980, by International Harvester

Engine

Engine options
International Harvester 5.1L 6-cyl diesel
International Harvester 4.8L 6-cyl gasoline

Engine Detail — 310 ci / 5.1 L Diesel

Manufacturer	International Harvester D310
Fuel Type	Diesel
Configuration	6-cylinder, liquid-cooled
German (Nuess) built diesel that replaced the 312 diesel in 1979.
Displacement	310 ci 5.1 L
Bore/Stroke	3.875x4.375 inches 98 x 111 mm
Rated RPM	2000
Starter volts	12

Engine Detail — 312 ci / 5.1 L Diesel

Manufacturer	International Harvester D-312
Fuel Type	Diesel
Configuration	6-cylinder, liquid-cooled
Displacement	312 ci 5.1 L
Bore/Stroke	3.875x4.410 inches 98 x 112 mm
Air cleaner	dry
Rated RPM	2000
Idle RPM	900-2000
Oil capacity	12 qts 11.4 L
Coolant capacity	21 qts 19.9 L

Engine Detail — 291 ci / 4.8 L Gasoline

Manufacturer	International Harvester C291
Fuel Type	Gasoline
Configuration	6-cylinder, liquid-cooled
Displacement	291 ci 4.8 L
Bore/Stroke	3.75x4.39 inches 95 x 112 mm
Rated RPM	2000

Transmission

Transmission — Torque Amplifier

Transmission	Torque Amplifier
Type	two-speed power shift
Gears	10 forward and 2 reverse
Oil capacity	64 qts 60.6 L
With 15.5-38 rear tires.

Dimensions

International Harvester 686 Tires
Ag front	7.50-16
Ag rear	15.5-38

Dimensions
Wheelbase	103 inches 261 cm
Length	162 inches*Overall length with 3-point hitch 411 cm
Width	89.4 inches*Minimum width 227 cm
Height (exhaust)	105 inches 266 cm
Diesel Shipping weight	7770 lbs 3524 kg
Ballasted weight	10340 lbs 4690 kg
Front tread	58 to 82 inches 147 to 208 cm
Rear tread	56 to 96 inches 142 to 243 cm

Tests

Tractor Tests
NTTL 1151: 312 diesel Torque Amplifier 2WD
NTTL 1152: gasoline Torque Amplifier 2WD
NTTL 1336: 310 diesel Torque Amplifier 2WD

Nebraska Tractor Test 1151
312 diesel Torque Amplifier 2WD November 3 - 14, 1973 Link: Nebraska Tractor Test 1151 file
PTO performance
Power at rated engine speed	66.29 hp 49.4 kW
Fuel use	4.7 gal/hour 17.8 l/hour
Drawbar performance
Max power	58.01 hp 43.3 kW
Fuel use	4.6 gal/hour 17.4 l/hour
Gear 3-Direct used for power test.
Max pull	8,012 lbs 3634 kg
Gear 2-TA used for pull test.

Nebraska Tractor Test 1152
Gasoline Torque Amplifier 2WD November 5 - December 3, 1973 Link: Nebraska Tractor Test 1152 file
PTO performance
Power at rated engine speed	66.30 hp 49.4 kW
Fuel use	12.0 gal/hour 45.4 l/hour
Drawbar performance
Max power	57.29 hp 42.7 kW
Fuel use	5.7 gal/hour 21.6 l/hour
Gear 3-Direct used for power test.
Max pull	7,981 lbs 3620 kg
Gear 2-TA used for pull test.

Nebraska Tractor Test 1336
310 diesel Torque Amplifier 2WD March 26 - April 16, 1980 Link: Nebraska Tractor Test 1336 file
PTO performance
Power at rated engine speed	66.36 hp 49.5 kW
Fuel use	4.1 gal/hour 15.5 l/hour
Drawbar performance
Max power	57.71 hp 43.0 kW
Fuel use	4.1 gal/hour 15.5 l/hour
Gear 3-Direct used for power test.
Max pull	8,013 lbs 3634 kg
Gear 1-Direct used for pull test.

Photos

International 686, right side.

International 686, left side.

Recommended Implements & Sizing Guide

Engineering recommendations for International Harvester 686 based on its 66.36 HP power envelope and ASAE agricultural standards.

Implement & Operation	Recommended Size	Workload Rating	Engineering Notes
Moldboard PlowPrimary Tillage	3 to 4 Bottom (16")3 - 4 铧 (40 cm)	Heavy Duty	Suitable for medium loam and stubble turnover.
Rotary Cutter / MowerMowing & Clearing	7 to 8 ft (84-96 in)2.1 - 2.4 m	Heavy Duty	Heavy-duty twin spindle cutter for overgrown acreage.
Rotary TillerSeedbed Prep	78 to 84 in200 - 215 cm	Heavy Duty	Heavy commercial tiller with multi-speed gearbox.
Disc HarrowSecondary Tillage	7 to 8 ft Tandem Disc2.1 - 2.4 m 对开双排耙	Medium Duty	Field leveling and clod breaking behind plows.
Hay BalerHay & Forage	4x4 to 4x5 Round Baler1.2x1.5 m 紧凑圆捆机	Heavy Duty	Silage and dry hay; 540 RPM PTO with slip-clutch.

Sizing & Soil Condition NoteActual implement sizing varies depending on local soil conditions (heavy clay vs sandy loam), field slope, and operating speed. Heavy tillage implements may require front ballast weights and wheel weights.

Fluids, Capacities & Working Autonomy

Standard fluid requirements, service intervals, and continuous runtime estimates for International Harvester 686.

Estimated Continuous Field Runtime: 9 hrs

Approximately 9 hours of continuous field operation at ~75% rated power on a full tank (31 gal / 117.3 L).

Estimated 75% Load Fuel Burn~3.5 gal/hr (13.1 L/hr)

Engine Crankcase Oil

SAE 15W-40 (Heavy Duty Diesel)

Standard Spec: API CK-4 / CJ-4 Heavy Duty

Service Interval: 150 – 250 Hours

Transmission & Hydraulic System

UTTO (Universal Tractor Transmission Oil)

Standard Spec: ISO VG 46 / 68 (Wet Brake & Trans Compatible)

Service Interval: 600 – 1000 Hours

Engine Cooling System

50/50 Ethylene Glycol Pre-mix

Standard Spec: ASTM D6210 / Heavy-Duty OAT Antifreeze

Service Interval: 2 Years / 1500 Hours