The Motor YEAR BOOK, 1951 JAGUAR MARK VII
Few cars have been so well established in their own particular niche as the Jaguar Mark V, which combined a 3½-litre pushrod engine with bodywork having traditional and highly attractive lines. The chassis of this car is a wholly post-war design incorporating independent front suspension with torsion-bar springs and Girling brakes, with two leading shoes on the front wheels. The engine, however, was introduced in 1937 and ever since the production of the twin overhead camshaft power unit of the same capacity for the XK 120 two-seater there has been speculation on the prospect of the new 3½-litre engine replacing the old for the saloon cars.
What probably no one expected was that there would be a new body and sundry other mechanical changes coupled with the foreshadowed switch of engines. The success of the Jaguar Company has, however, been built up on a series of attacking manoeuvres which have often seemed hazardous at the time they were effected and, true to form, the Earls Court Show of 1950 was dominated by the Jaguar Mark VII, which may be considered an entirely new car both in respect of appearance and performance.
The engine has been in no way de-tuned as compared with the XK. 120 and the 160 h.p. under the bonnet thus not only gives 28 per cent more than was available for the previous engine, but is the equal of any engine in quantity production irrespective of country of origin. Theoretically, this power output should raise the maximum speed to between 98 and 99 m.p.h., and would bring the car within the fastest half-dozen of its kind. The new body shape, however, in addition to offering obvious advantages in respect of appearance and accommodation, should have a substantially lower drag than the Mark V with its separate mudguards, and with an estimated top speed of over 100 m.p.h. Jaguars may well be able to claim that they have not only the fastest production car in the world, the XK 120, but also the fastest 4-5-seater saloon car on the market, the Mark VII.
Although the new styling improves the aerodynamic efficiency, respect is still paid to convention in the shape of a significant outline to the radiator cowling, whilst the sides of the body panels are cleverly moulded so that the car is wholly free from the drab, slab-sidedness which has been one of the weaknesses of post-war styling. Under the bonnet a useful change has been made by bringing the engine forward 5 in. along the frame and although the XK engine is 3 in. longer than its predecessor this move has improved passenger accommodation as well as increasing somewhat the weight borne by the front wheels which has in turn promoted an even softer ride.
Quite the most interesting technical change in the chassis is, however, to be found in the adoption of the new Girling auto-static hydraulic brakes. These have two trailing shoes in the front drums - an arrangement which entirely eliminates the servo-shoe effect characteristic of the two-leading shoe system. The advantage of the latter lies in greater braking effort for the given pedal pressure, but this is bought at the price of a considerable change in braking characteristics with rise in temperature. By using trailing shoes the influence of temperature change is much mitigated, and the performance of the brakes under really arduous conditions greatly improved. This scheme, however, would normally involve very much higher pedal pressures, and for this reason the driver's effort is supplemented on the Jaguar by a Clayton Dewandre vacuum servo unit.
The trailing shoes are self-adjusting so that apart from maintaining the fluid level the only attention needed is an occasional check on the hand brake, which takes effect in the rear drums where the conventional one-leading and one-trailing shoe arrangement is retained.
As a consequence of the forward mounting of the engine it has been possible to bring the rear seats sufficiently ahead of the rear axle as to eliminate entirely the encroachment of the wheel arches. The door openings thus coincide with the rear squab, and to make entry and exit even more easy the seat cushion corners are markedly rounded off.
The rear seat is divided by a 9½ in. wide folding armrest, the total overall width being 58 in. or comfortable accommodation for three persons. The width over the front seats is now no less than 57 in., but the seats are separate - a thing for which many buyers will be devoutly thankful. They are particularly well shaped and have both a sliding and vertical adjustment and, as at the rear the doors, are forward hinged and incorporate neat let-down fitted tool cases in the place normally occupied by pockets.
This housing for the small tools is bound up with the careful consideration which has been given to luggage accommodation. It is an unique feature of the Mark VII that the fuel is carried in two separate tanks situated in the rear-wheel fairings. Each tank has its own pump and supply line and this not only gives complete reliability in this important matter but also frees the luggage locker proper and, in conjunction with the vertically mounted spare wheel, provides an unrivalled cubic content. The rear-locker door has also been most carefully designed, with large handles which form the frame for the rear number plate.
The driving position of the car gives a view of both the front-wing contours through a wide vee screen which is matched by an unusual area of glass in the rear window. The glass in the rear doors is also carried unusually far backwards, and very great attention has been given to the ventilation problem. There are adjustable glass panels on all four doors, and the opening ventilators on each side of the wing fairings and in the centre of the scuttle, the last named admitting fresh air to the built-in heating and de-misting systems. Additionally, a sliding roof is retained.
The minor details of the beautifully schemed and finished interior include flushfitting sun visors, a map-reading light in the front compartment and reading lamps in the rear quarters, and an interior light worked by the doors. Instruments are illuminated by ultra-violet light, and there are large ashtrays accessible to every passenger.
Pierwsze (Moss) i drugie (Whitehead) miejsce w Tourist Trophy (GB).
Zwycięstwo (Appleyard) w Rajdzie Alpejskim (XK 120).
BRITISH AND BEST: lan Appleyard's Jaguar XK 120 which made the best performance in the French International Alpine Rally, irrespective of category, and lost no marks in this gruelling competition.