Ready for paint ….

Perhaps a good time to reflect back 50 years ago to early 1965 when Bob Blake had already made a start on the original’s monocoque.

At the time, it was believed that it was still possible to have the car up and running in time for Le Mans – time was very, very tight but the skilled team working behind closed doors were used to working to such tight deadlines.

From the perspective of the Competition Department Engineers, as described by Peter Wilson in his definitive book on the XJ13 (“XJ13 – The definitive story of the Jaguar Le Mans car and the V12 engine that powered it” – available from the publisher Paul Skilleter and the JCNA website )

… “That the Competition Department had the capability to build XJ13 to a similar schedule was in no doubt, especially as by 1965 there were three more people working in the department. One thing was missing, however – the final directive, which could only come from the top. To build E2A had required the entire CompetitionDepartment workforce, working seven days a week, together with similar levels of effort from the Experimental Engine Department to build and develop the 3.0 litre all aluminium racing engine. This total commitment from top management in respect of the XJ13 was not forthcoming probably due to other top level priorities which we couldn’t have been aware of …

… But it was becoming obvious that there was no way the car would be ready for Le Mans in 1965.”

The Competition in 1965

In January of 1965 the annual Racing Car Show was held at Olympia in London where the latest designs were being showcased by designers such as Lotus, McLaren, Lola & Brabham. Derrick White (Jaguar’s pre-eminent chassis designer) and Malcolm Sayer attended the show. They produced a report on their return in which Derrick made the following significant points:

  • None of the racing cars at the show adopted the practice of using the rear driveshaft to locate the rear wheels. Those of you familiar with Jaguar will know this had become standard practice at Jaguar. Companies such as Lotus and Lola had tried solid driveshafts as upper locating links but had quickly moved to upper/lower links and plunging driveshafts. This fell on deaf ears as far as Jaguar’s William Heynes was concerned and he insisted the XJ13 should retain Jaguar’s “production” setup. Jaguar’s bad experiences with the De Dion independent systems tried on the D-Types in the 1950s may have also influenced his decision. This difference of opinion festered between White and Heynes over the next two years eventually culminating in White leaving Jaguar and pursuing a very successful career designing race-winning chassis for Cooper and the Honda/Lola/Surtees consortium. There is no doubt the XJ13 would have ended up an even more competent car had Derrick been allowed to apply his solutions.
  • Derrick also made a request for more design resource – needed to keep pace with the competition. This request was refused by William Heynes who insisted a pair of hands should be recruited from within Jaguar’s existing complement.

Fast-forward …..

Fast-forward 50 years and to my efforts to reproduce the XJ13 rear suspension geometry.

I was already in possession of all critical suspension points in 3D space so I was well on my way to being able to reproduce the precise handling characteristics of the original car in my recreation. I had already sourced an original ZF 5DS 25-1 transaxle as used in the XJ13 – complete with identical ratios. As predicted by Derrick White, Jaguar did initially have problems with their use of the driveshaft as upper link and the transaxle output shafts had to be modified very early in development. I made the same modifications to the transaxle output shafts to cope with the lateral stresses applied by the use of the solid drive shafts.

Essentially, this consisted of replacing the ZF driveshaft circlips with nuts. The drive shafts were threaded and were held in place by nuts.

Driving the Rear Wheels

Incidentally, I have acquired a pair of drive shafts which had been originally installed in the XJ13. Indeed, it is possible they were in place during XJ13 Test & Development driver David Hobbs’ XJ13 record-breaking run – more than 161 mph on the closed track at MIRA in 1967 – a record which was to stand for 32 years and only beaten in 1992 by the McLaren F1 road car. This record did show the potential of the XJ13 “straight out of the box” and before serious race-development.

nsaxle output shafts before modification – showing circlip attachment
© Neville Swales
Original XJ13 modified transaxle output shafts installed in Neville’s recreation. These items are believed to have been in place in the original XJ13 during its record-breaking run.
© Neville Swales
Original XJ13 rear suspension. “Solid” drive shafts used as upper-links. Note custom cast alloy hub carrier and use of Dunlop brake piston.  
© Reproduced with permission

These output shafts are used to connect the cast rear hub-carriers to the transaxle via a pair of “solid” drive shafts. Again, those of you familiar with your Jaguars will recognise the basic architecture of this setup. The following picture shows the arrangement in the original XJ13:

I recreated the original setup – even going to the extent of recreating custom rear hub carriers, vented discs and custom Dunlop calipers. Although Jaguar later adopted Girling brakes, the car started its life with Dunlop brakes. A handbrake caliper was added but never used.

Sitting on all four feet

Original XJ13 front suspension (left). Based on 1964 Lightweight E-Type with peg-drive hub, vented discs, coil-over shocks in place of torsion bars, Dunlop caliper & removable pistons. Original XJ13 rear suspension (right). Custom hub carrier, peg-drive hub, Dunlop caliper, fabricated lower wishbone, vented disc and handbrake caliper (not used).
© Reproduced with permission
CAD drawing of XJ13 rear hub carrier. Jaguar used a similar process in 1965 but substituted pen & paper for the design and a wooden pattern for the 3D-Printed items! I chose to design his hub carrier so that larger bearings could be used. I also designed it such that wider wheels could be installed without the necessity to add rear wheel-arch flares. A hidden “drum-type” handbrake is incorporated into the design.
© Neville Swales

The following pictures show steps in recreating these custom items:

Heat-treated hubs arrive from the foundry in Coventry for my recreation.
© Neville Swales
Machining the hubs.
© Neville Swales

Batch of machined front hub carriers (left). These are cast using modern materials/treatment giving a strength approaching that of forgings. They are exact replicas of Lightweight E-Type items albeit modified to accept later sealed-for-life bottom bearings.

Front hub assembly (right). Lightweight E-Type hubs and custom vented disc.
© Neville Swales

With the rear hubs installed in the car, the front suspension could be completed.

Left (near-side) front suspension. Adjustable custom anti-roll bar is ¾” EN27 spring steel as original.
© Neville Swales
Left (near-side) front suspension. Note removable Dunlop brake piston fitted to custom cast replica caliper.
© Neville Swales

Oil

My car can now sit on all four feet. Dunlop racing tyres were fitted as original and attention could turn to final details as the recreated car was made ready for the paintshop. One of these details was the addition of a dry-sump oil tank as original. Wheras practically all modern tanks use round tanks where the oil is returned tangentially to remove entrapped air, Jaguar chose a different solution where returned oil passed over a series of baffle-plates in a rectangular tank. The following picture shows the original car’s dry-sump tank:

Original XJ13 dry-sump oil tank. Oil is returned to the top of the tank and passes through a number of perforated baffles for de-aeration before being stored in a lower rubber bag-tank in the sill.
© Neville Swales

The following pictures show the recreated tank. My tank does differ slightly from the original in that the de-aerated oil is stored within the sill in a solid aluminium tank rather than a rubber bag-tank. Much head-scratching was called for during the car’s build at Jaguar for a suitable rubber capable of withstanding hot oil at up to 150 C. I decided to take a more secure option! The tank is capable of holding more than 6 gallons of oil.

Recreated dry-sump oil tank. This picture shows the tank location on the rear left-hand sill. The tank base extends into the sill where de-aerated oil is stored.
© Neville Swales
Recreated dry-sump oil tank. This shot shows one of the sill stiffeners inside the sill. This helps give the structure immense strength as evidenced by Norman Dewis’ unintentional “crash-test” in 1971. The car’s underlying structure survived almost intact.
© Neville Swales
Beginning assembly of the replica oil tank components. The original tank was fabricated by Bob Blake himself. Whilst beautifully-executed, he did seem to favour the use of 3/16” screws which were used extensively. © Neville Swales 
This shot shows the first of the internal downward-sloping baffles being installed. 
© Neville Swales
Lots of 3/16” screws!
© Neville Swales
Final tank.
© Neville Swales

Just in case Malcolm is looking …

I have previously extolled the virtues of the craftsmen working at my chosen bodyshop – North Devon Metalcraft in Devon, UK. One more detail added a few days ago exemplifies the skill of these artisans. I reckon Jaguar’s Bob Blake would have approved had he still been around today.

I needed to install the front indicators. Knowing how particular Jaguar’s Malcom Sayer was about any detail disrupting his airflow, it was very important to ensure these items fitted particularly well and recessed into the aluminium body. Peter Wilson talks of an occasion in 1965 when Bob Blake took it upon himself to install a cast Jaguar emblem on the nose of the car. He carefully traced around it and hammered out a recess so the badge would sit flush. When Malcolm saw what he had done he immediately insisted the badge was removed, the recess removed and the nose hammered flat once more. Bob Blake reluctantly did so.

Wheras Jaguar’s rebuilt car has rows of raised rivets across its nose, the 1966 original made use of flat countersunk rivets in this area to maintain a smooth profile. I am sure the late Malcolm Sayer would not have been amused had he seen what was done to “his” car during its post-crash rebuild. The following pictures show the sequence followed by the chaps at North Devon Metalcraft to properly install the side indicators. I never tire of watching these skilled metalworkers at work:

First job was to fabricate a steel tool which could be mounted in a vice and used to form the recessed aluminium panel.
© Neville Swales
The panel was then held in position using a couple of self-tappers so that a line could be scribed around its perimeter.
© Neville Swales
A hole was cut by hand so the new panel sat absolutely flush with the surrounding metal. I had to look away while John of ND Metalcraft snipped the shape out of my pristine front wing by hand.
© Neville Swales
The confidence, speed and accuracy of the hand cut was quite remarkable.
© Neville Swales
The next step was to attach the panel using a series of tacks applied using TIG.
© Neville Swales
Panel tacked in position.
© Neville Swales
The next step was gas welding. The process of obtaining a continuous weld on such thin-gauge aluminium represents the height of the body-makers art. It has been described as “being constantly a split-second away from disaster”!
© Neville Swales
The finished weld. Now to make it disappear …
© Neville Swales
John begins his painstaking work to disguise the weld. He made it look easy which is the sign of a true craftsman.
© Neville Swales
The weld begins to disappear …
© Neville Swales
The finished item. No filler used and almost impossible to see or feel any kind of join. The final result is a recessed indicator which should have satisfied Malcolm Sayer himself.
© Neville Swales

CAN YOU GUESS WHAT THIS WAS FOR?

NACA duct positioned on XJ13 bonnet.
© Reproduced with permission

The bonnet of the XJ13 has a NACA (National Advisory Committee for Aeronautics) duct. It is placed on the driver’s side and close to the leading edge of the bonnet.

If you look underneath the bonnet you will see the following:

Recreated bonnet with duct as on original.
© Neville Swales

Can any of you guess what this was meant for?

Here’s a few clues … The duct points straight down. It points towards the steering rack and is in the vicinity of the brake and clutch reservoirs. It is positioned on the driver’s side rather than centrally on the car ……….

My car is now in the paintshop. The plan is to reunite it with its engine when it returns then give it a first shakedown run.

The words Jaguar, Jaguar XJ13, XJ13 are used in a historical/descriptive context and in no way suggest our recreations/replicas are approved by Jaguar. It is widely known that there was only ever one Jaguar XJ13 and any others can only ever be replicas, facsimilies, tributes, recreations, toolroom copies or similar.

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