Jaguar Mark X

The Jaguar Mark X (Mark Ten), later renamed the Jaguar 420G, is a large, luxury saloon car manufactured by British automaker Jaguar Cars between 1961 and 1970. It succeeded the Mark IX as the top of its range, but broke radically with its predecessors in both styling and technology.

From an industrial design viewpoint, the ponton-shaped MarkTen was a hallmark car for Jaguar by introducing the upright, often slightly forward leaning front fascia and grille, flanked by prominent quad round headlights. When Jaguar replaced its entire saloon range with a more compact single new model in the late 1960s, the resulting XJ6 of 1968 used the Mark Ten as a template.

Similar front grille and quad round headlight facias defined most of Jaguar's saloons for nearly half a century, until 2009 – the final year of both the 3rd generation XJ series, and of the Jaguar X-Type. Also, Jaguar did not build another car as large as the Mark Ten & 420G for the rest of the century, until the LWB version of the 2003 XJ Jaguars.

Introduced within a year of Jaguar's E-Type sportscar, the Mark X copied much of the E-Type's technology and specifications.

Mechanical

The Mark X was the first Jaguar saloon to feature independent rear suspension[8] designed by William Heynes, who was Jaguar's Technical Director and Chief Engineer. It differed from earlier large Jaguar saloons in having 14" wheels instead of the more common 15". It used a wider-track version of Jaguar's IRS unit first seen on the E Type, which was subsequently used on Jaguar vehicles until X308 production ended in 2003. The front suspension used double wishbones with coil springs and telescopic dampers.

Power initially came from the E-type's version of Jaguar's 3781 cc XK in-line six-cylinder engine designed by W Heynes, developing either 250 bhp or 265 bhp, depending on compression ratio.[9] A 9:1 compression ratio was standard, but an alternative 8:1 compression ratio was available as an option.[10] For the London Motor Show in October 1964 the enlarged 4,235 cc unit took over, although the 3.8-litre unit could still be specified until October 1965.[10] Triple SU carburettors were fitted, fed from an AC Delco air filter mounted ahead of the right hand front wheel.

Transmission options were manual, manual with overdrive, or automatic. The arrival of the 4.2-litre power unit coincided with the introduction of a newly developed all-synchromesh four-speed gear box, replacing the venerable box inherited by the 3.8-litre Mark X from the Mark IX, which had featured synchromesh only on the top three ratios.[10] Many domestic market cars and almost all cars destined for the important North American markets left the factory with a Borg Warner automatic gear-box. The 4.2-litre engine's introduction was also marked by a transmission upgrade for buyers of the automatic cars, who saw the Borg Warner transmission system switched from a DG to a Type 8 unit.[10] The power train was completed by a Thornton Powr-Lok limited-slip differential.

Stopping power for this heavy car came from power-assisted four-wheel disc brakes, the rear units being mounted inboard alongside the differential.[10]

Power-assisted steering was standard, the later 4.2 cars receiving Marles Varamatic Bendix (Adwest) variable ratio steering boxes, designed by an Australian, Arthur Bishop.[11]

420G

For the London Motor Show in October 1966 the Mark X was renamed the Jaguar 420G[1] (not to be confused with the smaller Jaguar 420). The 420G was distinct from the Mark X only with the addition of a vertical central bar splitting the grille in two, side indicator repeaters on the front wings, and a chrome strip along the wing and door panels (two-tone paint schemes were also available with the chrome strip omitted).

Interior changes included perforations in the central sections of the leather seats, padded dashboard sections for safety, moving the clock to a central position, and the introduction of air conditioning as an option.

A limousine variant was available on the standard wheelbase; a fixed, one-piece seat back topped with a sliding glass partition replaced the separate chairs of standard cars.

Despite running for the same length of time as the Mark X (five years) the 420G sold in less than a third of the numbers. This lack of popularity and the increasing production of the smaller XJ6 resulted in the 420G being run out of production in 1970.

Eight seater

In 1968 British Leyland ended production of the Daimler limousine DR450 and the Vanden Plas Princess and chose to replace them by offering a 141 in extra-long wheelbase 420G with an eight-seater Hooper "Empress Line"-inspired (but still monocoque) body made by Vanden Plas.[12] Aside from the shape of the rear part of the coachwork there was no link with Daimler cars made before Daimler became a subsidiary.

British Leyland's "Daimler DS420" was announced in June 1968.[12] Taller than the 420G the new car was nearly nineteen feet long and six feet six inches wide with "majestic proportions". The rear compartment carried six people in comfort on the rear seats and three fold-away occasional seats. Sir William Lyons pointed out it was less than half the price of its competitors.[12]

The 420G wheelbase was extended by 21", with the mechanical underpinnings of the car being subtly reconfigured. This eight-seater car was built until 1992 and used by many countries in official capacities. It was frequently used by funeral homes for carrying mourners or in modified form as a hearse.

manufacturer	Jaguar Cars
production	1961–1970 * 3.8 Litre: 13,382 * 4.2 Litre: 5,137 * 420G: 5,763
predecessor	Jaguar Mark IX
assembly	United Kingdom: Coventry, England
layout	FR layout
body style	4-door saloon
successor	Jaguar XJ6 (smaller)
class	Full-size luxury car (F)
length	202 in
wheelbase	120 in‡R1R‡
height	54.5 in
width	76.3 in‡R2R‡
weight	4200 lb
engine	3781 cc XK I6 (until 1965) 4235 cc XK I6 (from 1964)
transmission	3-speed automatic gearbox 4-speed manual box with overdrive
related	Daimler DS420
sp	uk

Body

Mechanical

420G

Eight seater

Scale models

See also

Further reading

External links

References