Speedmonkey: The First New Jaguar E-Type Lightweight In Fifty Years

Jaguar Land Rover's Special Operations division has built a brand new E-Type Lightweight, which will be the first of six.

2014 Jaguar E-Type Lightweight

In 1963 eighteen Special GT (aka Lightweight) E-Types were intended and allocated chassis numbers but only twelve were constructed. Now, in 2014, Jaguar has assembled a team of engineers to hand build the remaining six.

Working from the Browns Lane factory but utilising engineers from across the JLR group the first prototype has been finished and will revealed at Pebble Beach, California on 14 August.

The car weighs 1,000kg and is powered by a 3.8 litre 6-cylinder engine which produces 340bhp.

Here's some info, including full tech specs, from the press release plus a full gallery of the new E-Type Lightweight.

2014 Jaguar E-Type Lightweight

The bodyshell

The core component of the Lightweight E-type is its aluminium bodyshell. This material replaced the steel of the production E-type in the quest to shed weight – some 250lb (114kg) were saved compared with the standard car.

Despite the 50-year gap, the aluminium build of the six new Lightweights gives them an immediate affinity with the current Jaguar range, the F-TYPE and XJ models being built to exacting standards with aluminium bodies for exactly the same reason. In fact, Jaguar is now the world's leading manufacturer of aluminium-bodied cars and the company has unrivalled experience in the relatively new field of applying aluminium technology to volume production cars.

So when tasked with the job of recreating the Lightweight E-type's aluminium body, today's Jaguar engineers could relate at once to what their predecessors had achieved 50 years before. However, despite the enormous advances in technology since the early 1960s, the decision was taken not to incorporate modern materials or fixing methods. While high-strength aluminium alloys and bonded structures would have been invisible, they would not have been true to the original design – and nor would they have conformed to the FIA’s homologation requirements for historic racing.

Instead, today's advanced technology was deployed to ensure the highest quality and most faithful rendition of the Lightweight E-type's open two-seater body components. Using state-of-the-art scanning technology, the inner and outer surfaces of a Lightweight bodyshell were digitally mapped.

The resulting massively detailed scan, which recorded dimensions and shape down to a fraction of a millimetre, was then assessed by Jaguar's technicians to validate how the body was assembled back in the 1960s, how consistent the structure was side-to-side, and how it could be engineered today to produce the highest quality result for the Lightweight E-type project.

As this digital capturing process gave Jaguar's engineers complete control over the Lightweight E-type body's 230 individual components, their shapes could then be optimised before the data was sent to the tool room at Jaguar's Whitley engineering centre. Even panels which are unseen within the structure have been faithfully reproduced. To ensure absolute symmetry, one side of the scanned body was used as the datum, this being 'flipped' to produce an identical condition on the opposite side.

Additionally, before being signed-off, the outer ‘A-surface’ CAD scan was transferred to Jaguar's design department where the surface geometry was finalised. All this work ensured that the tooling from which the majority of the new body parts are produced is as accurate as possible.

Approximately 75 per cent of the panels are made in-house at Whitley, just a few very large pressings being supplied by external specialists using Jaguar-designed tooling. The grades of aluminium used for both the under-structure and surface panels are almost identical in mechanical properties to those used for the original 1963 Lightweight E-types. The body is completed to original Lightweight E-type Chassis no. 12 condition, by which time Jaguar had added some additional strengthening in key areas of the shell. The aluminium body is then completed by the addition of an aluminium bonnet, doors and trunk lid. As with the original cars, an aluminium hard top is standard.

The development of the body-in-white tooling was undertaken by the same department that builds all Jaguar Land Rover prototype vehicles, so the expertise applied to the project was world-class. The build process and assembly procedures were initially proved out on Car Zero; this is effectively an engineering prototype and will not carry one of the six Lightweight chassis numbers.

For the Lightweight E-type project, Jaguar's engineers created a 'grey book' of the type used during the development of new production Jaguars. This internal document sets out the required quality standards in terms of bodyshell fit-and-finish and ensures a consistency of build quality for all six new Lightweight E-types.

A roll-over cage is fitted as standard, and the body includes mounting points for a detachable front extension which is available as an extra. The cars are built in a form suitable for FIA homologation for historic motorsport purposes (see full specification).

The engine and drivetrain

The Lightweight E-type was powered by a highly developed version of Jaguar's straight-six XK engine which, with its chain-driven twin overhead camshafts and aluminium head with hemispherical combustion chambers, remained highly advanced in 1963 even though it had first been seen in the XK 120 as far back as 1948.

It was this engine that had powered the C- and D-types to five Le Mans victories in the 1950s, and the unit developed for the Lightweight E-type is based on the 3,868cc (236 cu in) engine which, in the D-type, had won Le Mans in 1957. A similar big valve 'wide angle' cylinder head is used, but in place of the D-type's cast iron block, Jaguar introduced an aluminium block for the Lightweight E-type which substantially reduced the amount of weight over the front wheels. This also features in the present-day car, with pressed-in steel liners.

Another major feature transferred from the D-type is the dry sump lubrication system. This uses a scavenge pump to collect oil from the sump and return it to a separate oil tank in the underbonnet area. This eliminates oil surge during fast cornering and consequent risk of damage to the engine's bearings, and also allows a greater quantity of oil to be carried.

The compression ratio is 10:1 and today's car is supplied with three 45DCO3 Weber carburettors. These were homologated by Jaguar for the Lightweight E-type in addition to a Lucas mechanical fuel injection system – which is being offered to customers as a cost-option (and which is fitted to Car Zero). The exhaust manifold is a steel fabrication and leads the exhaust gasses into twin pipes which take them through a centre silencer box to the rear of the car, where the exhaust system ends in twin polished tail pipes.

Whether carburettors or fuel injection is specified, brake horsepower is well over 300, and with torque in the region of 280lb ft at 4500 rpm, the car is endowed with rapid acceleration from comparatively low engine revs – a traditional feature of Jaguar racing engines.

A 12 volt negative earth electrical system is used, and the engine benefits from a modern inertia-type starter motor. The water and oil radiators are in aluminium alloy, there is an aluminium expansion tank for the coolant, and the fuel tank is mesh-filled for safety.

The power is transferred to the road via a lightweight, low inertia flywheel, a single-plate clutch and a Jaguar close-ratio, manual four-speed all-synchromesh gearbox as used by the Lightweight E-type in period. A variety of final drive ratios are available, all with the Powr-Lok limited-slip differential, but a 3.31:1 ratio is supplied as standard.

Suspension, steering and brakes

The twin wishbone front suspension and independent wide-based wishbone rear suspension (where the drive-shaft serves as the upper link) are set-up according to period racing practice, with uprated shock absorbers controlling the torsion bar springs (front) and the four coil springs (rear).

The steering is the excellent standard E-type rack-and-pinion, with a traditional wood-rim wheel for the driver. Larger (12.25in) brake discs are fitted at the front, with the rear brakes being standard E-type. No servo is fitted.

The 15in diameter wheels are period type in the correct 'perforated' style, and like the originals are cast in magnesium alloy. Rim width is 7in front, 8in rear. Dunlop racing tyres are fitted, 6.00 section front, 6.50 section rear, both in CR65 compound.

Final assembly

The monocoque bodyshell is built at Whitley where it is mated to its tubular engine sub-frame – which is stiffened with gussets as for the original Lightweight – and then shipped to Jaguar's Gaydon facility for painting. From there it is then taken to Jaguar Heritage at Browns Lane where the car is built up with powertrain, suspension, brakes, steering, electrical items, instrument panel and soft trim.

This process takes place in a dedicated area close to where the original Lightweight E-types were assembled in 1963/64, and the work is undertaken by highly skilled technicians used to assembling extremely complex JLR prototypes.

It is at this stage that personal consultation with the customer dictates the final specification for each individual car – no two of which are expected to be identical.

Car Zero underwent a 15-day shake-down period at Jaguar Land Rover's test facility at Gaydon to prove out the car's dynamics and establish optimum suspension settings. This involved Mike Cross, Jaguar's Chief Engineer, Vehicle Integrity. Jaguar's engineers even established a 'design verification plan' for the car, just as they would do for an entirely new model. Each of the six new Lightweights will go through shake-down tests to ensure that they meet the required standards in terms of braking, handling and steering.

2014 Jaguar E-Type Lightweight

LIGHTWEIGHT E-TYPE SPECIFICATION

Engine System

Engine: Aluminium six-cylinder block, wide-angle cylinder head, dry sumplubrication, lightweight low-inertia flywheel

Displacement: 236.0 cu in (3,868cc)

Bore/Stroke: 3.46in/4.17in (88.0mm/106.0mm)

Valvetrain: 2 valves per cylinder, DOHC

Compression ratio: 10:1

Carburettors: Triple 45DCO3 Weber

Injection (optional): Lucas mechanical, 6.25in (158.7mm) butterfly trumpets

Crankshaft: Steel with steel H-section con rods

Power: 340hp/253.5kW @ 6500rpm

Torque: 280lbs ft/380Nm @ 4500rpm

Fuel tank: Mesh-filled 14-gallon (64-litre) capacity

Fuel pump: Standard E-type

Transmission and Driveline

Transmission: Jaguar 4-speed all-synchro close-ratio gearbox

Final drive casing: Cast iron, Powr-Lok limited slip differential, axle ratio 3.31:1

Gearbox oil: Castrol

Clutch: Single dry plate

Suspension and Steering

Front: Double wishbone, LWE torsion bars, uprated anti-roll bar

Rear: Jaguar independent rear suspension lower wishbones/driveshaft links, radius arms, anti-roll bar (C/O Standard E-type rear springs with uprated damper assemblies)

Steering: Standard E-type rack-and-pinion, adjustable steering column

Brakes

Brake discs (front): 12in Dia (305mm)

Brake discs (rear): 11.25in Dia (286mm)

Handbrake: Production E-type

Wheels and Tyres

Magnesium disc
wheels: Front: 15in x 7.0J, Rear 15in x 8.0J

Tyres: Dunlop (Front - 6.00L15 CR65, Rear – 6.50L15 CR65)

Electrical

Battery: 12v - 62 amp / hour

System: 12v negative-earth

Lighting: Tungsten headlamps and standard rear tail-lamps

Ignition: Electronic

Instruments: Smiths Industries

Generator: Production E-type

Starter: Production E-type

Control Box: Production E-type

Wiper motor and blades: Production E-type

Exhaust and Cooling

Exhaust: Fabricated steel manifold, steel exhaust system with centre silencer box and twin polished tail pipes

Cooling: Aluminium E-type radiator, aluminium expansion header tank, engine oil cooler, oil sump tank

Overview

Length: 175.3in (4,453mm)

Width: 66.9in (1,700mm)

Height: 46.5in (1,181mm)

Weight: 2204.6lbs (1,000kg)

Wheelbase: 96.1in (2,440mm)

Front Track: 50.0in (1,270mm)

Rear Track: 55.0in (1,397mm)

BODY TRIM & HARDWARE

Body in white & closures

Aluminium monocoque with stiffened front sub-frame for race engines above 300bhp

Riveted and welded aluminium construction

Aluminium body closures (bonnet/doors/trunk-lid)

Aluminium detachable hard top roof

21 louvre bonnet air intakes

Black powder-coated roll cage

Front brake cooling ducts integrated with bonnet structure

Exterior trim

Side bonnet-release handles

‘Long range’ aluminium quick release fuel cap

Body colour cabin ventilation air intakes

Protective car cover (non-waterproof)

Centre bonnet catch

Oval door mirror upgrade

Interior Trim

Aluminium bucket seats with increased backrest angle and padded cushions

Rear-view mirror

Leather selection from Connolly palette

Wood-rimmed steering wheel

Aluminium gear knob and standard hand brake

Machined metal toggle and push button starter

Five-point seat belt

Black instrument panel with glove box

Bonnet and boot stands

Glass house

Clear laminated front screen

Perspex side windows and rear screen

Manual slide side windows