In the ’50s and ’60s, diesel-powered light trucks and SUVs were not common. The cranky diesel technology of that era didn’t translate well to the average Jane or Joe used to turning a key and driving away. Plus, the fuel delivery infrastructure wasn’t there to support it either. For all that, Jeep was among the first in America to offer a diesel in a non-commercial, large-production vehicle. Starting in 1961, a Perkins 4.192 diesel (sometimes advertised as the Four 192) was on the options list for the CJ-5 and CJ-6 through 1968.
Frank Perkins started the company in 1932, and Technical Director Charles Chapman designed a new lightweight, high-speed diesel that took the diesel engine more than a few steps farther into the mainstream. It was an immensely successful company from then on and has supplied engines to just about every industry that needs powerplants. Perkins is still in business today.
It isn’t clear what motivated Kaiser Jeep to begin offering a diesel. The most likely answer is to meet export demand and counter Land Rover and Toyota, which were stealing many of Jeep’s export markets. What is clear is that the Perkins was a great fit into the CJ and gave it diesel economy with approximately the same performance as the gas four.
The Perkins 4.192 made 192 cubic inches from a 3.5-inch bore and a 5-inch stroke. It cranked out 62hp at 3,000 rpm but 143 lb-ft of torque at 1,350 rpm. It was one of Perkins’ old-school, three-main-bearing, direct-injected engines that was in production from ’58 into ’72. It was seen in the Massey-Fergusson 65 tractor and in stationary and marine applications worldwide.
The end result of the Perkins option was a 30-mpg CJ that could almost keep up with the gas four, especially at lower speeds. And it could definitely out pull it. It used the standard T-90 three-speed and the rest of the powertrain was the same as the standard CJ according to the year of manufacture. We have not seen exactly what other features were unique to the diesel CJs, but it wasn’t a long list.
The diesel Jeeps came with a special serial number prefix. From ’61-’63, it was 57558 for the CJ-5 and 57758 for the CJ-6. From ’64-’68 (production ended in ’68 according to available documents, but there are sales numbers for ’69), the prefixes were 8310 for the CJ-5 and 8410 for the CJ-6. Exact production isn’t clear from research. Available records were spotty, but the starting CJ-5 serial number for the ’61 CJ-5 was 10,001 and the ’68 model year started at 11,156, which would indicate 1,156 CJ-5s to that point. Using the same logic with the CJ-6, there would have been 589 to that point. Unless there was a surge of production in 1968, it’s likely there were just under 2,000 of both types built.
Surprisingly, Perkins-powered CJs are seen fairly often, even if they aren’t plentiful. The diesel may bring a slight premium in the collector’s market, but overall condition always trumps the powerplant. Parts for the Perkins mill are still available and most of the rest of the Jeep is just like any other of the era. There are a few engine parts unique to the Jeep, such as the thermostat housing and bellhousing. Owners say they are fun to drive, peppy to about 50 mph, and very, very economical. We don’t know anyone who has wheeled one in a hardcore way, but the diesel would likely have more grunt than the F-head four, is immune to stalling, and could be a great crawler.
Vehicle: 1966 Jeep CJ-5 Diesel
Serial Number Range: 10,813 -11,892 (to Jan 1, 1968: calendar year not model year)
Engine: four-cylinder, DI diesel, Perkins 4.192
Power: 62hp @ 3,000 rpm
Torque: 143 lb-ft @ 1,350 rpm
Transmission: 3-speed manual, T-90
Transfer Case: 2-speed, Spicer 18
Front Axle: Dana 25
Rear Axle: Dana 44 semi-float
Axle Ratios: 5.38:1
Wheelbase: 81 inches
L x W x H: 135.5 x 71.7 x 69.5 inches
Curb Wt.: 2,550 lbs
GVW: 3,750 lbs