Jeep Tornado engine

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Jeep Tornado
Also called6-230
Typestraight six
PredecessorWillys Super Hurricane
SuccessorAMC Straight-6 engine
Bore3.34375 in (85 mm)
Stroke4.375 in (111 mm)
Displacement230.5 in³ (3.78 L)
Block alloyIron
Head alloyIron
Power output140 hp (100 kW) at 4000 rpm
133 hp at 4000 rpm
Specific power0.61 hp/in³
0.58 hp/in³
Torque output210 ft·lbf (280 N·m) at 1750 rpm
199 ft·lbf at 2400 rpm
Compression ratio8.5:1

The Jeep 6-230 Tornado engine was the first 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 only in Jeeps.

The Tornado, like most Jeep engines, was undersquare for better low speed torque. It had a 3.34-inch (85 mm) bore with a 4.38-inch (111 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 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: