APR 01st 2015

Magnesium vs Aluminium, The Jaguar XJR Meets Its Racing Grandfather

Racing a Mk VII Jaguar in the early 1950s must have seemed as logical trying to water-ski behind the Queen Mary. They looked like cars more suited to carrying coffins than racing drivers, at least until you saw one in action. Then it would blunder up to any given corner and appear to attempt a Western Roll all the way into the apex. The unintended consequence of this is that Mk VIIs looked so spectacularly inept they became the darlings of the local sports photographer, so their unique approach to describing a curve has been preserved for all time.


And, were Mk VIIs actually as bad as they looked, I’d never be writing this now. But, with the possible exception of the Citroen 2CV, there has never been another car with a greater gulf between the way it appears to handle to the outside world, and how the car actually feels inside the cabin. Sir Stirling Moss, who raced it in the ’50s, described his feelings for the car thus: ‘I have the warmest affection for the old Mk VII for, although it looked like a great waddling dumpling and made such a business of going round corners, it was actually very well balanced and light to drive.’

He first raced one at the Daily Express International Trophy meeting at Silverstone in 1952, took pole position, fastest lap and won the race. At the same meeting the following year he repeated his hat-trick and would doubtless have done the same in 1954 had the starter not jammed on the line of the Le Mans-style start, which meant he could only come third. Still, he did get pole and fastest lap and the race was won by another Mk VII, which just goes to show how much more competitive they were than their maiden aunt appearance might suggest. Mike Hawthorn won the race in ’55, claiming the Mk VII’s fourth straight victory in the event and most improbably of all; a Mk VII even won the 1956 Monte Carlo Rally.


But, even by 1954 the Mk VII was becoming something of an old girl, for a car that had never been designed to race and, despite now concealing D-type power under her skirts, what was needed more than anything else was a diet. Which is where the story of the car you see begins. Or at least the chapter that is relevant to us. For the record ‘KRW 621’ is a very old Mk VII, the sixth right hand drive car ever built and the one used by the works for all sorts of gruelling durability testing in 1951, before being given both a new chassis and, for our purposes rather more importantly, a new body too.

‘I have the warmest affection for the old Mk VII for although it looked like a great waddling dumpling, it was actually very well balanced and light to drive’

Chris Keith-Lucas of CKL Developments, who looks after the car today, reckons that as many as three lightweight Mk VII bodies were ordered, but if the others even got built, it seems this is the only one that has survived and that makes it a very special car. Clad in panels made from magnesium no less, it would be fascinating to see how much less than a standard 1700kg, steel-bodied MkVII it weighed: I imagine it would be measurable in the hundreds of kilos.


The car was sold to the famous Jaguar test driver Bob Berry and, while never raced in period, has found fame late in life being raced at the Goodwood Revival by former owner Rowan Atkinson and none other than Sir Stirling himself before being passed to its current keeper who continues to allow it to be raced, most recently by CKL’s managing director Ben Shuckburgh at 73rd Members Meeting. Boasting a healthy 3.8-litre engine, with perhaps double the 160bhp of a standard 1951 Mk VII, Dunlop disc brakes, lightweight E-type wheels and, of course, that magnesium body, if ever there were a tiger in elephant’s clothing, you’re looking right at it.


Charmingly, the Mk VII retains all its original interior trim, including the flat front seats across which Stirling would slide ‘like the carriage on a typewriter’. It smells musty and old and every second of the over half a century that separates it from the new Jaguar parked next to it. It’s there for a reason: KRW 621 was Jaguar’s very first lightweight full sized saloon, and the XJR is the latest. Indeed Jaguar has clasped the kind of lightweight construction espoused by the Mk VII so closely to its heart in recent years that that it remains the only manufacturer making full sized saloons with aluminium bodies and monocoques. And here the saving in mass is rather easier to quantify; the XJR weighs 1870kg, which may sound a lot until you compare it to a largely steel rival like the BMW 760iL M Sport, which tips the scales at 2250kg, making it fully 380kg fatter than the Jag. There are entire cars that don’t weigh much more than that.

Click here to read about driving the MkVII and XJR…

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