Classic Engine: Jeep’s Tornado Straight-Six

Posted on 12. Jun, 2012 by in Auto News

The two faces of the tornado. The motor is out of the J-series Wagoneer or truck configuration shown with the standard paper air filter and a generator.

Story by Jim Allen

Jeep overhead cam six, known as the Tornado was one of the first mass-produced overhead-cam engines in the United States built after the Second World War. As whiz-bang as that sounds, the engine is actually very humble roots.

Willys engine engineer AC Sampietro developed a simple plan: In 1960, he took the existing low-end architecture of the Kaiser Supersonic / Continental Red Seal 226-cubic-inch L-head (or flat) six and began to draw up a new overhead cam engine around.

The 226 engine had been in the Jeep lineup as the Super Hurricane recorded in 1954, and it had an enviable reliability record. It made 105 hp, and when it was introduced, it was a welcome addition to the PS-starved Jeep engine range. Like all flatheads, it had difficulty breathing and cooling, but Continental's Source engine was almost legendary for durability in jeeps and many other applications where it served until 1973.

Sampietro engine comes to life in February 1961, when the prototypes were tested. In May, the engine had passed the 100-hour full-power certification and the first production engines came off the assembly line in April 1962. The 230-cubic-inch engine was called Tornado, and in a strange twist of fate, the first Jeeps, they do not have the new Gladiator J-Series pickups or SUVs, but the old Wagoneer Willys cars and pickups, they were replaced.

Although the basic architecture of the tornado came from the 226 blocks were significantly different, not least the use of the lack of concrete encased connections and valves on a flathead engine and the lack of a camshaft. It was also full-flow oil filter, which had not been specified L226. The tornado had. The same stroke as the Super Hurricane and only slightly larger bore The crankshaft was more or less the same used in the 226, but it was reinforced by Tufftriding. This was one of the first times the cure was used by an OEM engine manufacturers.

Here the power and torque graph for the motor is as intended. Notice the torque curve. Jeep engine rated at 210 pounds-feet at 1,750 rpm. This curve shows, reach 210 pounds-feet from 1,000 rpm and holding above the approximately 3,700. Well, that's a torque curve!

The overhead cam system was unique because a cam lobe, the intake and exhaust valves open at each cylinder. This made for a unique camshaft profile, but it allows the intake and exhaust valves, exactly in the spherical (do not call it a Hemi) combustion chamber for optimum breathing in crossflow head position. The valves were large for the shift – 1.88-inch intake and 1.62-inch exhaust system. A good number of parts on the engine were made of aluminum, including the front cover, water pump, valve covers and intake manifold. The engine weighed 575 pounds, about 40 pounds lighter than the 226 Flathead.

Despite the tornado-long-stroke configuration – a 3.34-inch bore and 4.48-inch stroke – there was a bit of a revver heart. In fact, the motor of 140 HP at 4,000 rpm and 210 pounds-feet of torque at 1,750 revolutions per minute was underestimated. If Sampietro wrote about the tornado in November 1962 was bench testing of the two-cylinder engine was 155 hp and 230 pound-feet of torque (gross) and BSFC (brake specific fuel consumption) of 0.45 £ / hp / hr 1,200 revolutions per minute up to 4,000 revolutions per minute. Sampietro also designed a 153-cubic-inch, four-cylinder version of the Tornado, which was built abroad.

On the ugly side, the problems with the oil consumption and leakage issues were mostly seen in the motor early days. They were relatively easy to fix, both in-warranty and production. Due to the oil consumption and the owners not checking the oil until it is too late, a relatively high number of engine damage was reported. Word spread, and although the problems largely solved by the next model year, followed by the bad reputation, and it holds true today firmly. The engine is relative complexity compared with the American standard motor of the day was also an issue for the less well-trained mechanics.

The tornado did not die when it dropped from the lineup in 1965. Its design and tooling was Industries Kaiser Argentina (or IKA), which had transferred compounds with AMC and Renault. The engine was used in the Torino, a Rambler American clone. With just a few upgrades, the engine with a standard 155-horsepower plane was sold and an Interceptor version with three adjacent draft DCOE Weber barrels two 176 hp. An economy that 181-cubic-inch version (3.34-inch bore and 3.44-inch stroke) was built as well. In 1973, the lower end of the seven main configuration file has been updated and has been set by the time the engine in 1982, there were 215-hp versions in circulation. It was used extensively in racing, and it has even gained some international victories.

The tornado appeared in uniform. The low-compression version was mounted a barrel of 1967-69 Gladiator-based M-715 military tactical trucks. It was mostly the same. Except for the waterproof components and the 24-volt shielded electricals Another difference was the removal of the front motor mount, one of the most important sources of oil leaks on the civilian motor. The block had bosses and the motor mounts were located there, adjusted the locations used for civilian AMC 232ci six.

The lower end of the tornado was unremarkable. Four main configuration file, long stroke, long stroke. The upper end was remarkable for the day, with a crossflow head and overhead camshaft. The high-compression (8.5:1) had a domed piston engines, while the low-compression engines flat tops. The spherical combustion chamber for optimum air circulation allows. If this head were fitted to a quadratic over seven main machine, it would have a real barn burner. In his long-stroke long-stroke configuration, it had "peakyness." Good torque, with a touch of

226ci the L-head, the basic dimensions of the lower end was the nuclear DNA of the tornado. It could be argued that a better engine for this adjustment would be chose. Engineer AC Sampietro the primary task was to develop the engine on a tight budget. This engine was originally developed by Continental Motors, a subsidiary of Kaiser Industries.