International Harvester IDI
Manufacturer International Harvester (1982–1986)
Navistar International (1987–1994)
Production 1982–1987 (6.9 L)
1986–1994 (7.3 L)
Successor Navistar T444E
Ford Power Stroke V8
Configuration V8
Displacement 420 cubic inches (6.9 L)
444 cubic inches (7.3 L)
Cylinder bore 4.0 inches (6.9 L)
4.11 inches (7.3 L)
Piston stroke 4.18 inches (6.9 L)
4.18 inches (7.3 L)
Compression ratio 21.5:1
Turbocharger Optional Single turbocharger (1993–1994.5 only)
Fuel system Indirect injection
Fuel type Diesel
Specific power 170 @ 3,300 RPM (6.9 L)
185 @ 3,300 RPM (7.3 L)
190 @ 3,300 RPM (7.3 L turbo)
Torque output 318 ft·lb @ 1,800 RPM (6.9 L)
338 ft·lb @ 1,800 RPM (7.3 L)
388 @ 1,400 RPM (7.3 L turbo)

The International Harvester IDI (from Indirect Injection) engine is a 4-stroke 8-cylinder Diesel engine used in International Harvester trucks and Ford F-Series pickups from 1982 to 1994. The engine had two displacements: 420 cubic inches (6.9 litres), which was used in Ford trucks from 1983 until 1987, and 444 cubic inches (7.3 litres), which was used in Ford trucks from 1987 until 1993 (naturally aspirated) and in 1993 and 1994 (turbocharged). These engines were replaced in 1995 by the Navistar T444E (7.3 L) engine, which was also marketed under the Ford Power Stroke name.


In 1981 Ford signed an agreement with International Harvester to produce diesel engines for their light truck line. This led directly to the production of the 6.9 liter IDI diesel. The engine was developed as a low cost, light weight diesel that fit where a V8 gas engine would, to try to convert their gas engine customers to diesel and to sell to Ford for use in F-Series light duty trucks and E-Series/Econoline vans. Before it could be sold to Ford however, Tenneco Inc. purchased in the "Harvester" division of International Harvester which was moved within their Case heavy equipment line. The remainder of what was International Harvester was renamed Navistar, which concentrated on engine and medium/heavy truck development. Consequently, these are actually International-Navistar IDI engines.


In 1987, the 6.9 liter engine was supplanted by the 7.3 liter upgrade, with over 300,000 6.9s shipped to Ford and countless numbers installed into medium-duty trucks, school buses, and the like. This engine features numerous improvements over the 6.9 liter, with most of the changes located in the heads; the block received an increase bore and select-fit pistons, while the heads received an enlarged prechamber, enlarged valve stem shields, harder valves, and other minor upgrades. The front cover was revised to reduce seepage.

Finally, in 1993 Ford made available a turbocharged edition of the 7.3L. An internally wastegated, AR.82 Garrett T3 series turbo was used as the OEM for the factory turbocharger system.[1] The systems was tuned to minimize performance loss at high elevation, rather than to improve peak performance. A primary limiting factor to the performance potential of the engine is an incredibly restrictive stock down-pipe. It is commonly believed, but not officially verified, that this is deliberate and due to Ford's impending release of the T444E (Powerstroke) engine. Factory turbo vehicles received numerous additional improvements. Pistons had an enlarged primary compression ring, added intermediate ring, an enlarged ring land and wrist pin, as well as an anodized piston face. Other improvements included tweaks to the injection pump, larger injectors, and an upgraded oil-coolant heat exchanger.[2]

Valve cover sticker from International-Navistar AT190 7.3 liter turbo-diesel engine as installed in 1994 Ford F-350 Turbo Diesel

Turbo-Diesel Identification Sticker

Fuel system Edit

These engines are unusual today in that the fuel system is entirely mechanical, though this was the standard for diesels of the day and indeed for the earliest fuel-injected gasoline vehicles. The fuel system also utilizes indirect injection which made it quieter than its predecessor. The indirect injection fuel system makes this popular among drivers who choose to run vegetable oil rather than petroleum fuel (the dual fuel tanks that some Ford trucks are equipped with further makes running vegetable oil easier). Both 6.9 and 7.3 liter engines use the Stanadyne DB-2 injection pump fed by a cam-driven lift pump.

See alsoEdit

References Edit

Smallwikipedialogo This page uses some content from Wikipedia. The original article was at International Harvester IDI. The list of authors can be seen in the page history. As with Tractor & Construction Plant Wiki, the text of Wikipedia is available under the Creative Commons by Attribution License and/or GNU Free Documentation License. Please check page history for when the original article was copied to Wikia

Community content is available under CC-BY-SA unless otherwise noted.