1981: Performance and Efficiency

January

Tom Walkinshaw of Tom Walkinshaw Racing (TWR) approached Jaguar with a proposal for them to join forces for the European Touring Car Championship (ETCC) for the 1982 season. The new FIA Group A regulations meant that the Jaguar XJ-S would be suitable for this championship, and the resemblance to the road cars from which they derived would mean a potential sales opportunity to enthusiasts. There were a number of changes to the regulations which included wheel arches and fuel tank capacity. There were no restrictions on the transmission and braking systems. Initially, TWR chose to use Jaguar’s tough four-speed gearbox then opted for an AP clutch and a five-speed Getrag gearbox. Modifications to the engine were permitted, but there were restrictions on valve lift, and the fuel feed had to be the “original system” which meant Lucas fuel injection.

John Egan knew of Tom Walkinshaw’s past victories, he was cautious when it came to putting the name of Jaguar Cars to something that might fall at the first hurdle. Egan agreed to provide the Jaguar facilities and technical assistance, but Jaguar kept at arm's length until TWR proved themselves. Tom Walkinshaw proved a savvy businessman when he obtained a lucrative sponsorship deal with the Motul Oil company. He became the UK distributor for the products of this French oil company and although very little was sold in the UK, this was a European championship and the promotional opportunities for sales across the EU was immense. Jaguar remained a “sleeping partner” and continued to supply cars and components for this venture.

During the early collaboration, Tom Walkinshaw worked closely with Ron Beaty of Forward Engineering and used their engine testing facilities, until TWR could establish their own. The rules governing the Group A cars could have been viewed by some as restrictive, however this wasn’t the case for TWR and the Jaguar XJ-S. For homologation the annual production figure had to be at least 5000 cars, which in fact was not achieved during the early days and was only exceeded in 1984, TWR's final season in European racing. 

May

For Group 44, the 1981 CRC Chemicals Trans-Am Championship was based around nine events and the season started on 17 May 1981. The new XJ-S attended every race and instead of “British Leyland” across the top of the windscreen, it now had “Jaguar” proudly displayed. Although 1981 was not as rewarding as 1978, Bob Tullius won three races. Over the three years that Bob Tullius had driven Jaguars XJ-S cars, he won 15 out of the 29 races that he competed in. 

Sir William Lyons awarded Bob Tullius with the first International Jaguar Trophy, an award that was conceived by John Steen of Atlanta and a group of Jaguar’s dedicated enthusiasts to honour outstanding contributions towards the evolution or the success of the Jaguar brand. Although this award was conceived outside Jaguar, it was later adopted by the company at a time when the employees and enthusiasts needed the morale boost.

July

After an initial period of success for the XJ-S, demand had reduced dramatically, and the market doubt and uncertainty had reduced sales to a mere trickle. A reputation for high fuel consumption, indifferent quality and poor residual value threatened the very existence of the future model range. As a result of an organisation management re-structuring within the marketing functions, demand exploded when the company introduced the HE  (high efficiency) engine on the 15th July. This gave the XJ-S an increase in performance but more importantly, there was a dramatic improvement in fuel economy, which had always been the car’s downfall. It was deemed as a revolutionary new economy development of the renowned V12 5.3 litre fuel-injected engine. The new cylinder head design potentially improved fuel consumption to more than 20mpg in out-of-town driving. 

The XJ-S HE was officially recognised as the world’s fastest production car with automatic gearbox, as apart from its improved fuel efficiency, it had a higher top speed of 155mph (249.5km/h).

The fuel consumption benefits were a result of the introduction of the “Fireball” combustion chamber. It was invented by the Swiss engineer Michael May and this was the first time the design had been used on a production engine. Jaguar’s engineers spent five years perfecting May’s principles to suit the demand of a production engine; the development was overseen by Jim Randle (Director of Vehicle Engineering) and Trevor Crisp (Group Chief Engineer – Power Units and Transmissions).

John Egan, Chairman and Chief Executive, commented: 

“While the performance and smoothness of the Jaguar V12 engine has always been regarded as nothing short of astonishing, we were aware that the unit’s fuel consumption, although gradually being improved, needed a major economy advance to reflect the world’s increasing energy consciousness."

The secrets of the “Fireball” lay in the split level combustion chamber arrangement, with the inlet valve set into a shallow collecting zone and the exhaust valve set higher up within the “bath tub” type combustion chamber, which also housed the spark plugs and a ramped channel connecting the two areas. As the piston rose during the compression stroke, the mixture charge was pushed out of the inlet valve pocket and swirled rapidly round into the main chamber. These characteristics ensured a rapid and complete burning of the very lean fuel mixtures. The compression ratio was increased from 9.0:1 to no less than 12.5:1. Power was now 299bhp at 5000rpm, with torque of 318 lb/ft at 3000rpm (European specification).

A decision was made to re-develop what was already a very reliable constant energy module. Initial thoughts centred on the idea of a separate ignition system for each bank of six cylinders with a double-deck distributor. It was discovered that the module could be made with a more powerful amplifier moving from 5 to a maximum of 8 amps, this would provide enough power for all 12 cylinders. After an extensive search, Lucas developed the novel solution of using a twin coil system, where the secondary coil was used solely as a large inductor. To keep the system cool, the coil was mounted in front of the radiator. The new ignition system incorporated a magnetic pick-up within the distributor and proved to be 100 per cent reliable throughout its development.

August

To accommodate manufacture of the new cylinder head, it was decided that investment should be made at the Radford Engine plant. The Company invested £½ million at Radford and most of the money was spent on four new transfer machines for the revised spark plug locations, together with a numerically controlled triple-head milling machine which finished machining the new combustion chambers. 

The objective of the Jaguar engineers was to ensure everything adhered to Jaguar’s high standards for consistent quality and reliability, and improved efficiency. With this in mind, they investigated means of removing potential areas where operator error may occur. The company introduced Programmable Logic Control (PLC) on the machine tools; a system of diagnostic fault finding on both the block and head which ensured consistent high levels of accuracy on all machining operations. It was reinforced by an electronic link-up of all the machine tool storage boards in the lines, this system signalled when the pre-determined tool life had expired which maintained the tools maximum efficiency.

Additional sophisticated electronic gauging systems were introduced in all areas where a high level of accuracy was essential. The machine accurately measured 26 separate ordinates (centre distance) in one single operation. The first machine of its kind to be installed at Jaguar meant the operation would be reduced from many hours of manual labour to just a few minutes. Arrangements were also made for machining the locations of the valve seat inserts, for shrink fitting the inserts and to take into account the differing depths of the new valve positions from the head joint face.

The Daimler site at Motor Mills was close to full capacity so Daimler bought the land and started building on what would become the Radford factory in 1906. When Jaguar took over Daimler in 1960 they transferred engine and powertrain components from Browns Lane to be built at Radford. The Radford factory continued to produce the commercial vehicles which ended 1973 when BL had a reshuffle of the business. By the time the XJ-S was launched Radford was assembling axles, building the XK and V12 engines as well as mating the gearboxes to the engine and then in 1983 the AJ6 engine was added. At the end of XJS production and moving to a V8 engine in the XK8 it was decided to move engine manufacture to the Ford plant in Bridgend, Wales. Radford closed in 1997.

The Lucas/Bosch P-digital electronic fuel injection system that was introduced in 1979 had some minor adjustments made. The improved power and torque characteristics allowed the use of a higher ratio (2.88:1) rear axle which in turn also aided the economy, cruising refinement and maximum speed.

September

Along with the new engine there were some external changes: New badges: The boot badge was changed from XJ-S to XJ.S and moved to the right-hand side; H.E. letters were added to the left-hand side of the boot panel; a round “growler” badge was added on the bonnet; and a silver on black Jaguar script badge was placed above the rear number plate lamp. On the side of the car, indicators were added to the front wings in front of the wheel

• A wider range of paint colours was offered
• Tapering twin coach lines were introduced in a contrasting colour
• Starfish alloy wheels
• New bumpers were introduced for the XJ-S that were similar to those previously used on the Series 3 saloon. The bumpers had the addition of chrome at the top
• Twin rear fog lamps were incorporated into the rear bumper and direction indicators were recessed into the front bumper

There were also differences made internally:

• Elm burr veneer was introduced for the first time on this model and was extensively used throughout the car
• The saloon style steering wheel was used, with thicker built-in horn push
• The introduction of all-leather upholstery and trim, including door trims, rear quarter castings, centre console, armrest and stowage locker supplied by Connolly
• A thick pile carpet was colour-keyed to the new range of interior trim and headlining colours

December

Jaguar worked extremely hard with regards to the quality and reliability of the cars produced, and it paid off. The new XJ-S HE lifted the sales for Jaguar and the volumes rose from 1533 in 1981 to 3458 in 1982. The upturn brought sales figures back to the levels achieved in 1976-78, and went on from there. The H.E. also benefited from Jaguar’s new methods of quality control. The company was beginning to experience the phenomenon of demand far exceeding the ability to produce, and customers had to wait for their cars.