The Legend

The International/Navistar DT466

- Jim Allen

Legend! That’s a powerful word that might be used a little too often these days. When it comes to the DT466 diesel, though, it fits. Especially, when you consider it came from users in the field before International’s marketing department got hold of it. The DT466 legend crosses into the industrial, agricultural and truck realms, but it was the medium-duty truck world where it made the biggest impact.

Early Days

Development of the International Harvester 300 and 400 series engines started in 1967. The prime mover for the project was the VP of the Construction Equipment Division of International Harvester, Bill Wallace, who saw a need for a new line of in-house designed and built engines. The Construction Equipment Division had its own engine section and that put them a little at odds with International’s main engine plant in Indianapolis. Reportedly, Wallace had an uphill struggle to get money allocated for the program but lobbied hard and eventually succeeded by expanding the idea to cover the other IH divisions, many of which needed a diesel upgrade.

The 300 and 400 lines are inexorably locked together, since they shared the same basic architecture, many parts and were built on the same tooling. The 300 line was more compact than the 400’s and shared a common bore of 3.875. It included the D312 (4.410-in stroke) and the D (Diesel, naturally aspirated) and DT (Diesel, Turbo) 360 (5.085-in stroke) diesels. The 400 line shared a 4.30-in bore and included the D and DT414 (4.75-in stroke), D and DT436 (5.00-in stroke) and the D and DT466 (5.35-in stroke). While the DT360 is a legend in its own right, we’ll save the details for another time.

Engineering