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How Mitsubishi Diesels Got Into mid-1970s Dodge D100 trucks

Mitsubishi dieselThe players:

  • Industrial Irrigation Engines built Chrysler industrial engines for irrigation from 1955 to 1995; they also used Mitsubishi diesels.
  • Pettit Automotive, local repair garage and tinker, used to work for Industrial Irrigation, before he retired and opened his own repair shop.
  • Spitz & Blauvelt Inc (SBI), a local aluminum foundry and the area’s largest job machine shop with welding and repair; it moved to Juniata, Nebraska in 1984 and became Phoenix Casting.

In 1977, Industrial Irrigation’s sales force got the bright idea that, to promote their newly-acquired Mitsubishi diesel line, they would convert some of their service trucks to diesel, and offer it as a conversion kit for farmers.

John C. (Jack) Osborne, Industrial Irrigation’s president (and the younger brother of retired Nebraska Cornhusker coach Tom), talked the idea over with Mr. Pettit and both felt this could be done, so a diesel engine and 1977 Dodge D100 truck were taken down to Pettit, where he started by pulling the gas and figuring what he needed to make to connect them back together. The D100 had a 360 and A727 automatic in it; later ones were done with manual transmissions.

We at SBI had just finished our first adapter to put a John Deere 4219 in a ¾ ton Chevy service truck for the John Deere dealer, Valley Engines in Wayne, Nebraska; this may have been where Industrial Irrigation got the idea!. We also did one for their 1 ton GMC to a JD 4239T; these engines are a bit heavy, at 950 lbs. for a 239 cubic inch diesel, but they do last forever.

We were two blocks south of Mr. Peditt’s shop, and he came down for help with the aluminum casting he needed for the adapter. We helped him design the adapter, made the wood pattern, cast the parts, machined them, and also made a steel part that went from the flywheel to the Chrysler flex plate. [Phoenix Casting still does this type of work for small runs.]

The Mitsubishi had one problem that showed up as soon as it was in the truck and running: the RPM was limited to 2400, which made for a great go-for in town, but a low top end of 48 mph. They dropped the rear gear from 3.56 to 3.07, and found the power curve now needed a turbo to help go over 45 mph.

They had the local injector wizards, the Fobin Brothers, work on the injector pumps to speed up the diesel. I seem to remember Zigy game up with a different injector pump that would run it up to 3500 rpm, but the conversion cost on that was more than the cost of the diesel! The John Deeres, on the other hand, could easily be cranked up to 3600 rpm (the valves float around 4200). Both of these trucks were still being used a few years back when I stopped by to check on them.

mitsubishi diesel

The Deere version was the forefathers of the adapter we make to day to convert SAE engines over to use Chrysler, GM, or Ford automotive style transmissions. You would be surprised at some of the requests we get today for adapters that people think should be in stock. As for the Dodge diesel adapter, we did four to six castings, and this adapter faded away. Still, having your own aluminum foundry has its advantages when it comes to making adapters.

Phoenix Casting & Machining of Juniata, Nebraska, makes small special one-off kids, adapting everything from small Snow Cats to Land Rovers to various engines. The shop is around four miles west of Hastings; Bill is the design engineer of SAE engine adapters for Phoenix castings, and is open to inquiries for special projects.

Postscript (from the Allpar staff)

When the fuel crisis hit, Dodge was not prepared, but perhaps someone heard of Industrial Irrigation’s work. In 1978 and into the 1980s, Dodge sold, as a factory option, the Mitsubishi diesels in D150s, D250s, and Power Wagons; the Mitsubishi 6DR5, was a straight six sized at 3950 cc, with 105 hp at 3500 rpm. It came without a turbocharger, providing good mileage (reportedly over 20 mpg) but limiting top speeds; the turbocharger was added by many buyers afterwards.

Mitsubishi diesel engine

CIS Auto Web wrote (in a wonderfully detailed article) that the Mitsubishi diesel was nearly identical to the Toyota Land Cruiser’s 2H diesel in every respect -- it had an almost identical Nippon Denso injection pump, and was approximately the same size and weight, with a similar power band. The 6DR5 was a factory option from the late 70s and early 80s Dodge trucks and came naturally aspirated from the factory; it had the Land Cruiser’s bolt pattern.

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