The Jeep 6-230 Tornado engine was a postwar U.S. designed mass-produced overhead cam (OHC) automobile engine. It was introduced in mid-year 1962 and replaced the flathead 6-226 Super Hurricane, which had been in use since 1954. It is still the only engine designed, developed, and built by Jeep and used exclusively in Jeeps in North America. It was also manufactured in Argentina by Industrias Kaiser Argentina (IKA).
The Jeep Tornado engine debuted in the 1962 Jeep Wagoneer station wagons (today called SUV) and Jeep Gladiator pickup trucks. It was the only U.S.-built overhead-cam engine in production at that time. The engine was designed for robust, heavy-duty performance with maximum efficiency. Its excellent fuel economy was proven in tests with the Tornado-OHC engine having the lowest specific fuel consumption of all production gasoline engines on the market.
The Tornado, like most Jeep engines, was undersquare for better low-speed torque. It had a 3.34375 in (84.931 mm) bore with a 4.375 in (111.1 mm) stroke. The standard version had an 8.5:1 compression ratio. Output was 140 hp (100 kW) at 4000 rpm and 210 ft·lbf (280 N·m) of torque at 1750 rpm. A low-compression (7.5:1) version was also available, with 133 hp (99 kW) at 4000 rpm and 199 ft·lbf (270 N·m) of torque at 2400 rpm.
The Tornado was a good engine; unfortunately, it was complex (by 1960s standards) and was discontinued in civilian vehicles in the U.S.A. in 1965. It continued to be used in military versions of the Jeep pickup, the M-715 and M-725, until 1969. One unique feature of the design was that the camshaft only had six lobes. One lobe operated both the intake and exhaust valve for each cylinder. This made engineering cam profiles a bit more difficult than conventional two lobe per cylinder (one per valve) designs, but allowed the valves to be better arranged for the cross-flow head. Valves were directly opposite their respective ports, and ports were short with wide radius turns.
Production of this engine continued in Argentina by Industrias Kaiser Argentina (IKA) after 1965. The engine was used in Jeeps and in the IKA-Renault Torino, a local version of the American Motors (AMC) Rambler American/Rambler Classic hybrid that was built in Argentina from 1966 to 1982. IKA was eventually bought out by Renault, but the Torino and the Tornado engine continued to receive upgrades over the years.
The engine name was changed to "Torino" to match the car in 1973. It also received a major block and crankshaft refinement that year — seven main bearings instead of the original four. In 1975 "IKA" was dropped from the company name and it became simply "Renault Argentina". The Torino (car and engine) continued production through 1982. From 1976 to 1982 it was the only non-Renault designed car made by the company. It was used in the following vehicles:
- Willys Jeep Truck 1962-65
- Willys Jeep Wagon 1962-65
- Jeep Gladiator 1963-64
- Jeep Wagoneer 1963-64
- Kaiser Jeep M-715 1963-69 (military only)
- Kaiser Jeep M-725 1963-69 (military only)
- Renault Torino, also known as IKA Torino, 1966–82
- Industrias Kaiser Argentina (IKA) produced Jeep vehicles from 1956–78