Vintage Diesel Light Trucks: Part One

A chronology of diesel-powered light trucks in America

Diesel-powered land vehicles go back a long way in U.S. history, but diesel light trucks are a relatively new part of the scene. Why? A combination of technology and finances. In the early days of diesel engines, downsizing them was a huge challenge. Given enough capital, engineers can work through almost any technical challenge. But investors want a return on investment so there needs to be market incentive. It’s very clear the engineers and inventors could have shortened the timeframe for the development of diesel-powered light vehicles but market demand always dictated the pace of development.

Diesels started as monstrous things in the 1890s suitable only for ships and stationary powerplants. By the 1930s engineers had them worked down to fit in the largest of trucks, smaller watercraft, tractors and construction equipment. By the end of the ’40s diesel technology was knocking at the door of offering practical diesel power for light vehicles but market factors still got in the way.

Among the biggest technical challenges were batteries. In a cost-effective sense, they hadn’t progressed enough to direct-start a diesel on a cold day without needing to make space for a lot of batteries. From the consumer standpoint diesel engines were noisy, smelly, rough as a cob and had very limited rpm ranges. The onerous startup process for a diesel engine in ’40s and ’50s America was more than most of the public would bear. On top of that, they delivered low power from what was still a large package. Even the base six-cylinder gassers on the market could outperform diesels small enough to fit in a light vehicle, not to mention the endlessly popular big American gas V8s. Not much infrastructure was available either, with diesel fuel stations few and far between, and service people were not on every corner.

United States market demand for light-duty diesels was at least 20 years behind Europe and didn’t reach any significant level until the 1973 gas crunch. After that, diesel power became one element in the car and light duty truck manufacturers’ frantic effort to supply high-economy vehicles. Those few who had been driving the sparsely available light-duty diesel products available here were suddenly transformed from nerdy geeks into forward-thinking role models. Every aspect of the infrastructure responded and by then the technology existed to make a diesel-powered car or light truck reasonably practical, if still a bit more onerous to run than your dad’s Oldsmobile.

Oldsmobile! Saying “Oldsmobile” in conjunction with “diesel” still prompts uncontrollable weeping in some circles. There are current and former General Motors executives in that crowd, not to mention GM customers of the ’78-81 period. Forty years down the road, the Olds Diesel is still near the top of many people’s list for GM’s “Days of Infamy” and is generally regarded as having single-handedly soured the American public on diesel cars and trucks. The diesel light-truck market recovered quickly with good products from many manufacturers, including General Motors, but the diesel car market has never bounced back nor realized its potential.

What you see here is a chronology of diesel-powered light trucks and SUVs available in the United States in significant numbers to about 1990. We’ve left out most of the oddballs and one-offs. Some will be familiar, some not so familiar. Good or bad, each had a part to play in where we are now.

Check back next month for the second half of our history of diesel discussion.

1957-73: Land Rover Series I and II Diesel SUVs and Pickups

In 1957, Land Rover introduced a 2.0L diesel as an option for its short- and long-wheelbase 4x4s. It was a modern IDI design that featured roller tappets and its base architecture was also used for the OHV gas engines that replaced an aging line of low-power F-head gassers. The diesel evolved from a dry-sleeved 2.0L into a parent bore 2.25L. Land Rover diesels were available in the USA on and off (mostly off) into 1973, when importation of all Land Rovers stopped. When Land Rover resumed importing vehicles in 1987, diesels were not on the American menu but LR diesels were still popular throughout the rest of the world.

Displacement: 2.0L (125.2ci)/2.25L (139.5ci)
Power: 52 hp @ 3,500 rpm/67 hp @ 4,000 rpm
Torque: 87 lb-ft @ 2,000 rpm/103 lb-ft @ 1,800 rpm
Compression Ratio: 19.5:1/23:1
Aspiration: Natural

1961-69: Jeep CJ-5 and CJ-6

Kaiser Jeep added the British-made Perkins 4.192 four-cylinder diesel to the CJ-5 and CJ-6 options list for 1961. The option ended in ’68 but Jeeps so-equipped were sold into ’69. Over the years of production just under 2,000 were sold. The 3.15L engine reputedly offered 30 mpg, with acceleration performance equal to the standard four-cylinder gas engine. The lower rpm redline tended to limit the upper end, so they pretty much fell over at about 50 mph with the standard Jeep 5.38:1 gearing. The Perkins 4.192 was one of the last of Perkins’s old-school, 3-main bearing designs and had appeared in 1958. Production of the 4.192 stopped in ’72. Jeep toyed with the idea offering this engine in other platforms but never took that leap. Until the ’80s Jeep’s many diesel offerings were limited to overseas markets.

Displacement: 3.15L (192.2ci)
Power: 62 hp @ 3,000 rpm
Torque: 143 lb-ft @ 1,350 rpm
Compression Ratio: 16.5:1
Aspiration: Natural

1964: Jeep M-676, M-677, M-678, M-679

The Jeep Forward Control pickups debuted for 1957 in a short-wheelbase half-ton FC-150 and a long-wheelbase one-ton FC-170, both four-wheel-drive. They were innovative cab-over trucks but didn’t set the light truck market afire. Sales were never better than adequate and had begun to taper off in the early ’60s. About that time, while trying to land a big contract for a new light tactical military vehicle, Jeep learned the Marine Corps was looking for a non-tactical all-wheel-drive rig with diesel power. They proposed a militarized version of the Forward Control, designed and built it, and got a contract. Starting in 1963 they began building the M-Series FCs powered by Cerlist 3-cylinder, 2-stroke, loop-scavenged diesels that made 85 hp from 170 cubic inches. They were built in four configurations, the M676 pickup, M677 four-door pickup, M678 and M679 Ambulance, and around 400 units of all types were known to have been built.

Displacement: 170 ci
Power: 85 hp @ 3,000 rpm
Torque: 170 lb-ft @ 1,900 rpm
Compression Ratio: 22:1
Aspiration: Natural (blower)

1963-68: International Harvester C-Line Trucks

In 1958 International began debuting a new line of six-cylinder diesels in several displacements, among them the D301. Displacing 301 cubic inches, it was the parent bore version of the sleeved D282 (282 ci) used in tractors and it was intended to be a lighter-duty variant for automotive use, among other applications. The engine was planned for the lower GVW end of the IH medium-duty truck and bus line but eventually it was developed into a special-order option for the IH light-truck line. The earliest known light trucks with D301s appeared in 1963 and the last in 1968. Though a relatively short and limited run, these are the first diesels available in a production American light truck.

Displacement: 301 ci
Power: 112 hp @ 3,000 rpm
Torque: 228 lb-ft @ 1,600 rpm
Compression Ratio: 18.2:1
Aspiration: Natural

 1976-80: International Scout II, Traveler and Terra

For 1976 International introduced a diesel option to the Scout lineup. The Nissan CN6-33 6-cylinder diesel debuted at the same time as two long-wheelbase Scouts, the Traveler SUV and the Terra pickup. The engine came from Chrysler-Nissan, which was a joint distribution venture between Nissan Motors of Japan and Chrysler Corporation. This agreement lapsed soon after the IH agreement and distribution reverted to Nissan. The Nissan designation for the 198ci NA six was SD33 and it was one of a family of four- and six-cylinder diesels used in a variety of applications. From its introduction in Scouts through the 1979 model year the SD-33 was naturally aspirated and rated at 81 horsepower. For 1980, the last year of the Scout, an uprated 6-33T turbocharged version was offered and rated at 101 horsepower. The diesel was a relatively popular option in Scouts and the engine created a stellar reputation for reliability, even if it wasn’t a powerhouse.

Displacement: 3.3L (198 ci)
Power: 81 hp @ 4,000 rpm/101 hp @ 3,800 rpm
Torque: 137.5 lb-ft @ 2,000 rpm/175 lb-ft @ 2,200 rpm
Compression Ratio: 22:1/20.7:1
Aspiration: Natural/Turbocharged

 1978-81: Chevrolet and GMC C10 Pickup

This is the truck side of the 1978 Olds 350 diesel debacle. That same year it was added as an option for the very lightest-duty half-ton, two-wheel-drive Chevrolet and GMC pickups under the Ordering Code LF9. This engine was less problematic in trucks than in the cars because truck owners were a little more diesel-savvy and didn’t do some of the silly things that got car owners in trouble. Still, the trucks had their trouble and ’78 and ’79 were the worst years. Most of the issues were fixed by 1980 and the engine was available through 1981 in full-size trucks, replaced for ’82 by the all-new 6.2L diesel.

Displacement: 5.7L (350 ci)
Power: 125 hp @ 3,600 rpm
Torque: 225 lb-ft @ 1,600 rpm
Compression Ratio: 22.5:1
Aspiration: Natural

1978-79: Dodge D and W100, D and W200 Pickups

Dodge also jumped on the full-size diesel truck bandwagon in 1978. Their D and W150 (half-ton) and D and W200 (three-quarter ton) models of that year featured a six-cylinder diesel option, namely a superb 3.98L Mitsubishi inline six (6DR5). Available only in ’78 and ’79, it shared general design architecture with the 2.6L diesel four that would come later to the Ram 50 imports. This was an extremely good engine, but being naturally aspirated with only 100 hp on tap it was outclassed in light trucks with up to an 8,400-pound GVW. With the optional automatic performance was even less inspirational. Yeah, it was another diesel victim of bean counting that failed to inspire the truck-buying public to go diesel. Had Dodge opted for the turbocharged 6DS5 variant, at about 130 hp and over 200 lb-ft, the diesel engine could have at least matched six-gasser performance.

Displacement: 3.98L (243 ci)
Power: 103 hp @ 3,700 rpm
Torque: 168 lb-ft @ 2,200 rpm
Compression Ratio: 20:1
Aspiration: Natural

1979-85: Toyota Pickup

The first Toyota pickups came to the U.S. Market in ’64 and were first offered with a diesel here for 1979. Until 1983 the diesel option was for two-wheel drive only but was added to the four-wheel-drive line for ’83. The ’79 diesel was the 2.2L Model L and came only in naturally aspirated form. For ’84 the naturally aspirated 2.4L (Model 2L) engine replaced it. For ’85 both the 2L and the turbocharged 2L-T were offered. These engines were available in the U.S. through 1985. The L-Series Toyota diesels originated in 1977 and continue in production today. Toyota has long offered diesels elsewhere in the world but didn’t focus much on marketing them here.

Displacement: 2.2L/2.4L (146ci)
Power: 62 hp @ 4,200 rpm / 75 hp @ 4,000 rpm/84 hp @ 4,000 rpm
Torque: 93 lb-ft @ 2,400 rpm/114 lb-ft @ 2,400 rpm/ 137 lb-ft @ 2,400 rpm
Compression Ratio: 21.5:1/20:1
Aspiration: Natural/Turbocharger

1980-82: Volkswagen Rabbit Diesel Pickup

Built in VW’s Pennsylvania factory and introduced in 1979 as a 1980 model, the Rabbit pickup was billed as a stylish light-duty hauler. The design originated in the American market but soon emigrated overseas and became known as the Volkswagen Caddy. With only 48 hp, the early 1.5L pickup ran a whopping 17 seconds to 60 mph. For 1981 the pickup got an updated 1.6L diesel that made 52 hp and the unit could make 60 mph in about 15.5 seconds. Slow, yes, but you got 40-50 mpg. The Euro market got a turbocharged Caddy later on. While these cool little trucks were only offered here through ’82 they were built in PA through ’84 for other markets and continued to be built in various VW factories around the world until 1996. While a gas engine was offered in these cute little rigs the diesel was the most common variant here.

Displacement: 1.5L (90 ci)/1.6L (97 ci)
Power: 48 hp @ 5,000 rpm/52 hp @ 4,800 rpm
Torque: 56.5 lb-ft @ 3,000 rpm/72 lb-ft @ 3,000 rpm
Compression Ratio: 23.5:1 /23:1
Aspiration: Natural

1981-86: Datsun/Nissan Pickups

Datsun, a brand of Nissan Motors, began the importation of cars and trucks to the U.S. in 1958. The first diesels didn’t come until mid-year 1981 as an option in the two-wheel-drive 720 Series trucks, some of which were built in a new Tennessee plant starting in 1983. They were badged “Datsun” into 1983 and “Nissan” thereafter, with a smaller “Datsun” badge for a transition period. From ’81-83 the diesel was the Nissan SD22, which was a 2.2L NA engine related to the SD33 six-cylinder that had appeared in the Scout and other vehicles in the 1970s and after. In ’84 the SD25 was introduced and carried the Nissan diesel option to its American conclusion in ’86.

Displacement: 2.2L (132 ci)/2.5L (152 ci)
Power: 61 hp @ 4,000 rpm/70 hp @ 4,000 rpm
Torque: 102 lb-ft @ 1,800 rpm/115 lb-ft @ 2,000 rpm
Compression Ratio: 21.6:1/21.4:1
Aspiration: Natural

1981-87: Isuzu P’up and Trooper II

In 1981, after nearly a decade building the LUV for GM, Isuzu decided to market its mini-truck under the Isuzu banner and, unlike the LUV of the same era, that included a diesel option. The P’up was the familiar LUV now finally bearing its own badges. For 1984 the Trooper II SUV was introduced and a diesel was on the options list. Both had the same C223 2.2L NA diesels as the LUV and the S-10 to 1986 and the C223T turbo diesel was an option in both for ’86 and ’87. The Isuzu diesels were gone from the United States after that but soldiered on elsewhere in the world for some years.

Displacement: 2.2L (136.6ci)
Power: 62 hp @ 4,300 rpm/80 hp @ 4,000 rpm
Torque: 93 lb-ft @ 2,200 rpm/128 lb-ft @ 2,200 rpm
Compression Ratio: 21:1
Aspiration: Natural/Turbocharger

1982-93: Chevrolet and GMC Light Trucks and SUVs

GM introduced the 6.2L V8 diesel into 1982 model year Chevrolet and GMC trucks and SUVs. Developed by Detroit Diesel, then still a GM subsidiary, the light-duty, indirect-injected (IDI) diesel engine was a ground-up development for trucks with no more than a 10,000 GCVWR. The 6.2L had no direct roots to the ill-fated 5.7L/350 Olds V8 diesel offered in earlier GM products. The GCVWR would be bumped a little later. The early emissions engines were generally seen at 130 hp with 240 lb-ft. Non-emissions versions for higher GVW trucks could go a fair bit higher. These were great engines in the half-ton pickups and added a lot to the Blazer and Suburban. In the three-quarter and one-tons, not so much. Being NA meant they had to be flogged mercilessly with a heavy load. Reliability suffered and they delivered disappointing performance. In lighter applications they were well-liked as being economical and proved more durable. Again, cost cutting was the root of whatever evil existed in the 6.2L. GM later learned that the engines with aftermarket turbo kits actually held up as well or better than the NA in hard use and offered much better performance. The 6.2L evolved into the 6.5L, most of which were turbocharged. While the 6.5L turbo diesel never equaled the competitors from Ford and Dodge in the ’93-2000 era, it settled in to be a good offering, especially in the half-ton lines. The 6.5L engine is still in production, though not by GM.

Displacement: 6.2L (379 ci)
Power: 135 hp @ 3,600 rpm
Torque: 240 lb-ft @ 2,000 rpm
Compression Ratio: 21.5:1
Aspiration: Natural