BILL VANCE AUTO HISTORY
1960 Valiant introduces the ‘slant-six’ engine
By the late 1950s the big North American carmakers were becoming concerned about the rising tide of imported cars led by the German Volkswagen. To respond, General Motors, Ford and Chrysler decided to produce their own smaller cars. When introduced late in 1959 as 1960 models each of their compacts had a different character. The Chevrolet Corvair’s air-cooled, flat-six, rear engine design was so clearly influenced by the Volkswagen that it was called an “American Volkswagen.” Ford, being managed by the no-nonsense, no-frills president Robert McNamara, produced the starkly functional Falcon that brought bland styling and a conventional front engine, rear-drive configuration. Chrysler’s Valiant (it became the Plymouth Valiant in 1961) also had a conventional layout but was a little more adventurous. Although not as daring as the Corvair, it was bigger and more powerful than the others. It had a somewhat “European” styling theme with a simulated continental spare tire stamped into the trunk lid and trapezoidal grille inspired by the Chrysler 300. The Valiant’s wheelbase was slightly shorter than the Falcon’s and Corvair’s but its overall length of 4,674 mm (184 in.) was 76 mm to 102 mm in. (3 to 4 in.) longer. This provided extra overhang that gave stylists a freer rein and contributed to a slightly larger trunk than the Falcon’s (25 cu ft versus 24.5). The Corvair’s rear engine layout severely compromised trunk capacity, allowing only 9.8 cubic feet in front and 4.5 behind the rear seat. The Valiant’s 1,247 kg (2,750 lb) weight was some 136 kg (300 lb) heavier than its competitors. All three had unit construction rather than the then more conventional body-on-frame (all Chrysler products except the Imperial adopted unit construction for 1960). Suspension was by longitudinal torsion bars in front, a rather daring feature for an American car. At the rear was a conventional solid axle with leaf springs. The Valiant ran away from the other two in performance. With its 101 horsepower compared with Falcon’s 85 and Corvair’s 80 the Valiant was clearly the quicker car. Road & Track recorded zero to 97 km/h (60 mph) in 13.9 seconds for the Valiant, 17.7 seconds for the Falcon and 19.5 seconds for the Corvair, all with three-speed manual transmissions. The Valiant’s top speed was 153 km/h (95.2 mph) compared with the Falcon’s 140 km/h (87 mph) and the Corvair’s 142 (88). The Valiant’s performance superiority came from its bigger engine, the outstanding newly developed overhead-valve, inline “slant-six.” It was Chrysler’s first overhead valve six and displaced 2.8 litres compared with Falcon’s 2.4 litres and Corvair’s 2.3. The slant six would become Chrysler’s workhorse engine for 28 years powering everything from compacts to luxury cars to trucks. It replaced the venerable side-valve six that dated back to the 1930s, and the engineers gave it sturdy internals. Its four main bearings were a generous 70 mm (2.75 in.) diameter and the hefty crankshaft weighed 29.5 kg (65 lb), making the Corvair’s 11 kg (24 lb) crank look almost puny. The engine was sturdy enough to allow Chrysler to add another 25 mm (1 in.) to its 79 mm (3.1 in.) stroke. This and the 86-mm (3.4 in.) bore produced a 3.7 litre, 145 horsepower unit which was powerful enough for Chrysler to use in its large vehicles. This more powerful engine was made optional in the Valiant by 1962 and the smaller 2.8-litre version would be enlarged to 3.2 litres in 1970. The cylinder head and block were cast iron, although aluminum was tried briefly in the early 1960s. A 4.4 litre (273 cu in.) V-8 became a Valiant option in 1964. The slant six was tilted 30 degrees to the right, not for the usual purpose of achieving a lower hood line but to produce a shorter engine. Engineers placed accessories such as the water pump on the side of the block and this and a more slender cooling fan allowed the engine/transmission to be mounted farther forward for increased leg room. Slanting the engine also resulted in longer intake-manifold runners which gave a slight “ram” or “natural supercharging” effect. The Valiant also had the distinction of replacing the generator with an alternator that provided higher electrical current at lower engine rpm. The slant six was produced in Chrysler’s engine plant in Trenton, Michigan from 1960 to 1984 and was built in Windsor, Ont., for a few years. But time and circumstances eventually saw it replaced by the smaller, lighter 2.2 litre, K-Car four cylinder engine. The slant six was gradually squeezed out as demand for the 2.2 increased. Valiant was a very successful nameplate for the Chrysler Corp., introducing both the sturdy slant six and the alternator. It would outlast both Corvair and Falcon, being built until 1977 when it was replaced by the Plymouth Volare.