1959 Jaguar MK IX

Jaguar Cars, Limited introduced the Mark V four-door sedan in 1948 featuring a new chassis with independent double-wishbone front suspension. It made its debut alongside the XK120 at the London Motor Show and came equipped with the pre-war pushrod inline six-cylinder in lieu of the new XK engine. The Mark VI was replaced in 1951 with the Mark VII and was the first sedan to be endowed with the race-proven dual-overhead-cam inline-6 XK engine. (The Mark VI was omitted to avoid confusion with the Bentley Mark VI).

The Mark IX was announced on October 8th of 1958 and was the final evolution of the styling and chassis introduced with the Mark V. The 3.8-liter version of the XK engine delivered 220 horsepower and Dunlop disc brakes were added to all four wheels, the first for a production Jaguar. In the event of an engine stall, the brake system would rely on a vacuum reserve tank.

For the United States market, the Mark IX came with an automatic transmission and power steering. Otherwise, a four-speed manual transmission was standard while the overdrive and a Borg Waner three-speed automotive were optional. Cars equipped with the automatic received a hill-holding 'anti-creep' feature, that when the vehicle was at rest and the brake pedal was released, an electromagnetic valve maintained brake pressure, preventing the car from rolling. The Borg-Warner DG automatic gearbox system would shift from first to second when a dash-mounted switch was toggled and could remain in second gear indefinitely. The third gear operated via a series of clutches that allowed direct drive rather than through the torque converter. The standard final drive was 4.27:1 except when the overdrive was installed, which used a 4.55:1 ratio.

The DOHC straight-6 XK engine retained the B-type head of the Mark VIII, but with an enlarged bore and a 3.8-liter displacement size. A chamber at the bottom of the combustion chamber made it possible for the larger bore size. Twin HD6 1.75-inch SU carburetors were installed, and a smaller electromagnetically controlled auxiliary carburetor was positioned between the two SU carbs to act as a choke. This arrangement proved troublesome and many were eventually converted to manual switching.

The steering of the Mark VII and VIII models had 4.5 turns lock-to-lock, but the powering steering system of the XI, with its Hobourn-Eaton pump attached to the back of the generator, was geared at a more responsive 3.5 turns lock-to-lock.

The Jaguar Mark VII chassis had a 120-inch wheelbase, an overall length of 196.5 inches, and was 75-inches wide. Its suspension was similar to the Mark VIII (which used a setup similar to the Mark V of 1949) with a torsion bar independent front setup with a live rear axle with leaf springs.

The appearance was similar to the VIII, except for the 'Mk IX' emblem on the trunk lid. Pricing for the four-door sedan began at just over $6,000. From 1959 through 1961, a total of 10,009 examples of the Mark IX sedan were produced, including 4,647 built for export.

Along with four-wheel servo-assisted Dunlop disc brakes, the Mark IX was the first Jaguar to employ recirculating ball power steering as standard equipment. A sunshine roof was also standard equipment for the U.K. market Jaguars. The bodies could be painted in either single or twin-tone paint schemes, and the interiors were given luxurious accouterments such as deep pile carpeting, burled walnut, and leather. The styling was very similar to its predecessor, the Mark VIII, distinguished by the addition of a chrome 'MK IX' badge on the trunk (boot lid). The later version of the Jaguar Mk IX had a larger tail-lamp assembly with the addition of an amber section housing the direction indicators.

During the production of the Jaguar MK IX, it would be joined briefly by the sporty XKSS and the Mark 1, both were produced through 1959. The two-door XK150 had been introduced in 1958 and remained in production through 1961 when it was replaced by the E-Type. Along with the four-door MK IX saloon, Jaguar buyers could also purchase the Mark 1 (produced from 1955 through 1960) followed by the Mark 2 (1960 through 1967). The Mark I was smaller than the IX with a wheelbase size of 107.5-inches and powered by a 2.5 and 3.4-liter XK inline-6. Production of the Mark I far exceeded that of its larger and more luxurious sibling, the MK IX, with 37,397 examples sold. Nearly 84,000 examples of the Mark 2 were built between 1959 and 1967.

In 1961, the Mk IX was replaced by the Mark X (Mark Ten), later renamed the Jaguar 420G. It took over the duties of its predecessor, being the top-of-the-line, luxurious, exclusive saloon car during its decade-long production lifespan.

by Daniel Vaughan | May 2019