Jaguars are historic
If and when the projected V12 Jaguar engine ever appears and ultimately replaces the 21-year-old six-cylinder XK engine, the twin .o.h.c. six must surely go down in the annals of automobile engineering history as one of the classics of all time. Its competition history is equally impressive, culminating in its use in the very advanced and beautiful-looking D-type models which were conceived for the sole purpose of winning the Le Mans 24-hour race. The D-type Jaguar first appeared in 1954 and, apart from the works racing team cars, was built in considerable numbers for sale to the public, something like sixty cars being built and sold all over the world, from Mexico to Australia.
Recently, while motoring in the North of England in our 1970 E-type roadster, we called on Neil Corner to visit one of the E-type's ancestors, for Corner owns, and races in Historic Sports Car Club events, a well known and famous D-type Jaguar. As the D-type was phased out of production it was due to be replaced by the XKSS, which was a direct descendant, being a fully equipped touring version of the D-type, intended to replace the XK150 sports car. The great fire at Jaguars in 1957 caused the XKSS to be still-born, apart from sixteen pre-production models, and during the following years the D-type and XKSS design was improved into the now classic E-type which appeared in 1961. Corner's D-type was a 1955 works team car, XKD 504, with extended nose cowling and built-in tail fin on the headrest and originally had a fuel-injection engine. In 1957, it passed to Ecurie Ecosse. who registered it RSF 302, the number it still carries, and it is now back in Jaguar dark racing green colour.
Putting the E-type roadster and the D-type racer side-by-side the parentage was clear to see, not only in the general shape but also in the engine and chassis layout and construction, the square-section tubular framework extending forward from the cockpit bulkhead of the monocoque centre-section being almost identical, while parts like front suspension wishbones looked almost interchangeable. The D-type has a dry-sump lubrication system, with a large aluminium oil tank on the left-hand side of the engine, against the E-type's normal wet-sump system, and being 3.8-litres to the E-types 4.2-litres it can rev to 6,000 r.p.m. against the production car's 5,500 r.p.m. As well as the D-type Corner owns a Lightweight E-type, these being competition versions of the production car built around a standard E-type roadster, with a fixed hard-top, Lucas fuel-injection in place of the triple carburetters, a ZF five-speed gearbox, Dunlop alloy wheels and aluminium body panels. Both of Corner's cars were ready to run at a touch of the starter-button, so a very enjoyable afternoon was spent progressing backwards in Jaguar history. Familiarisation of the roads of County Durham was first made in the 1970 E-type, in the smooth effortless silence and comfort that is one of the features of the modern Jaguar, and then a run was made in the Lightweight E-type. There was no doubt that one was in an E-type, but the controllability and performance were vastly superior, though everything seemed rather harsh and noisy in comparison with the standard car. The ZF gearbox was rather horrid, the ratios being good, but the gear-changing mechanism being rather vague and unpleasant and it was easy to understand why Jaguars designed and built their own all-synchromesh four-speed for the 4.2-litre car, to replace the dreary old Jaguar box that dragged on so long from the original XK 120 models. The smoothness and liveliness of the competition engine was very impressive and obviously a lot of care had been taken in balancing and lightening all the moving parts, a time-consuming business that could not be applied to the production E-type engine. At 5,000 r.p.m. on the production engine you are conscious of a great lump of machinery whirling round in front of you, but at the same figure in the competition car it was incredibly smooth and well on its way up into the next 1,000 r.p.m.
The overall feeling on the Lightweight E-type was that here was a vastly superior version of the normal car, meant for serious motoring rather than "promenading" and that we might as well leave Corner our 4.2-litre roadster and set off south in the Lightweight, and be home in two-thirds of the time it had taken to travel to the North. The next step backwards, into the D-type, was another matter altogether, for immediately you were in a racing car and the only similarity was the smooth way the six-cylinder engine ran up to 6,000 r.p.m., with the most shattering noise from the two long tail-pipes, devoid of any silencing. This was another world altogether, completely enclosed in the tiny cockpit with very little point in looking anywhere except straight-ahead or down at the huge tachometer, trying to keep the r.p.m. down to 5,500. The D-type has the old agricultural Jaguar 4-speed gearbox, but with racing close-ratios so that it was quite acceptable compared to an XKI20 gearbox, and 3rd to 4th at near-peak revs was very satisfying. Being used for Historic racing this D-type is geared for 150 m.p.h. at peak r.p.m., but in its heyday at Le Mans it could approach 180 m.p.h. The lower ratio gave the car shattering acceleration and it went up to 125 m.p.h, in a manner that was very exciting. Compared to the E-type and the Lightweight E-type it felt decidedly twitchy on its road-holding for the D-type was built before Jaguar discovered independent rear suspension. It has a one-piece axle located in all directions by rods and levers and sprung on transverse torsion bars, a set up that was adequate for the billiard-table Le Mans surface in 1954-55, but archaic compared to sports-racing cars such as Lancia, Ferrari, Maserati and Mercedes-Benz of the same era. This was very obvious when anyone tried to race a D-type at the Nurburgring and the performance by Hawthorn when he nearly beat the Mercedes-Benz 300SLR team at Dundrod in the Tourist Trophy was heroic beyond belief. Even on the open road at speeds of 100-120 m.p.h. the rear end of the D-type felt awful compared to the later E-types with their i.r.s. but it was gratifying to have first-hand experience of the progress Jaguars have made in ride and road-holding even if they haven't made much progress in engines. On a seemingly smooth dual-carriageway at 100 m.p.h. the D-type was desperately trying to shake its rear axle off, but could not do so because it was so well anchored to the chassis, with the result that the rear axle shook the whole car. In spite of this the D-type was the most fun of the three Jaguars and there was no feeling that you wanted to set off on a long journey or do any serious motoring, you just wanted to blast about freely on any inviting road that appeared. The whole car exuded a feeling of "racing car", from the conveniently placed rest for the clutch foot and the strategically placed sponge rubber for the knees to the shattering exhaust note. The low Perspex screen wraps round alongside. the right ear, to join the headrest, and the passenger's side of the cockpit is firmly covered over by a metal panel and the driving seat is really tailored for a long-distance race, the cockpit interior being matt black, SO that you are in a different world.
It was with great reluctance that the D-type was returned to its owner, but it was needed for a race at the Crystal Palace, which incidentally it won from another ex-works D-type, number 3CPF. Quite by chance this second D-type was encountered a short while later when it was changing owners and the chance for a ride in the passenger seat was accepted without hesitation. We were involved in a little private dicing on a large country estate in the Midlands and were following a Formula 5000 McLaren on rather damp and greasy roads and at once it was very noticeable what great advances have been made in rear suspension and traction, even leaving out the wide-tyre factor. 3CPF started life as a 1954 works car being chassis number 406, the sixth to be built, and is devoid of tail fin on the headrest and has the short stumpy nose cowling, which gives the car a remarkably small overall appearance.
Another D-type to appear recently in Historic racing is number 554, brought back from America by the Hon. Patrick Lindsay, this car having been exported to a customer in Mexico when it was new.
D-type Jaguars seem to be turning into "collectors items" so it is worth noting the following facts in case anyone tries to sell "the actual Le Mans winner, old boy".
In 1954 six cars were built for the factory team, these being XKD 401 to 406, and Ferrari won Le Mans.
In 1955 XKD 501 to 575 were laid down on the assembly line, some being works team cars, a great number being sold as "production racers", five being destroyed in the 1957 fire, four being dismantled for spares and sixteen being made into XKSS models.
in 1956 six cars were built for the factory team. Two of these passed to the Ecurie Ecosse the following year.
In 1955 Hawthorn/Bueb won with XKD 505 running on Coventry Trade Plates.
In 1956 Flockhart/Sanderson won with XKD 501, now in Scotland registered MWS 301, and in 1957 Flockhart/Bueb won with XKD 606 registered RSF 301, though it ran the race on Scottish Trade Plates. D. S. J.