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Jaguar model numbering

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Graham Lyons

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Numbering of models of English cars is a mysterious thing at the best of times but there is usually a reason for model numbers. Does anyone know why the numbering of the big Jags started at Mark V? Where did XK come from (120 and 120C I know about)? And while we're at it, what about the XJ in XJ6? Is it just the next one on from XK?
 
Graham,

I just read the history of the XJ on the all-new XJ model page on jag-lovers.org. Under the heading of "XJ Heritage Milestones" you will find the answers to the model name mystery for the XJ line. Apparently, the "XJ" stood for "eXperimental Jaguar" initially. Here is a quote from that section:

"The car that became the first XJ was originally known by its internal project number, XJ4. The XJ stood for 'eXperimental Jaguar'; there was no particular significance to the number 4."

The link to the XJ350 page is https://www.jag-lovers.org/x350.html .

It is an interesting read and answers many more questions regarding the naming and numbering of the cars. I hope you find this helpful.

Regards,

Brian
 
Scurrilous thought, I know, but in 1939 Bentley had introduced a MkV too, and the Jaguar wasn't too dissimilar in appearance, though of course a few years later.
 
I will attempt an extemporaneous and rambling note about where the various Jaguar model designation came from. The Mark series began before WW2 with models Mk II and Mk III that were sedans based on an Austin chassis and running gear. The Mark IV came after the war as a similar Austin engined sedan and was updated in style by a MK V. Inexplicably the V was followed by a VII, VIII, IX and X; the VI designation was not used.
The sports models of pre war Jaguars were designated by SS followed by a number such as 100 relating to a technical feature. Since after the war the "SS" was universally rememberd ignominously as the Nazi elite, the term was dropped for PR reasons and replaced by Jaguar. SS probably was derived from Standard Swallow. The Standard comes from the Austin Standard supplied chassis and engines and the Swallow comes from Lyons first and successful manufacturing endeavor of motorcycle side cars termed Swallows in the 1920s and 30s. All of the SS cars had Austin supplied running gear complemented by a custom and sporty-for-the-times coach work.
During the war and between air raids on Coventry, the gentlemen from SS in England designed the historic XK dual overhead cam straight six while acting as German bomber spotters. (This was in the midst of aircraft wing production). After the war the XK engine set the world land speed record in Belgium circa 1948 in a hand made aluminum XK120 prototype. Thus the run of XK120, XK140, XK150 and XKSS. The SS was sneaked in meaning super sports.
The racing model C types and D types was followed by the production E types. Some of the designations were followed by "C" or "M" meaning C type or modified. The XJ designation probably meant experimental Jaguar and came from XJ40 meaning the engineering effort to design the second generation Jaguar 6. The current XK8 draws directly from the venerable XK straight six.
If the above is confusing, then just wait until Ford gets into the Jaguar model name designations. You havent seen anything yet. I sincerely hope that this somewhat responds to your question. Best regards, Jack.
 
Sorry, Jack, but you've got yourself a bit muxed ip!
Swallow Sidecars was the first Lyons company, and though there were Swallow bodies on Austins, most notably the Seven, later pre-Jaguar creations were on Standard engine and chassis bases, not Austin. There's no such animal as an Austin Standard - Austin were Austin and Standard were Standard. Austin went on to become part of BMC, and Standard became part of Standard-Triumph. When the great merger under Deadly Stokes took place, it all became BL.
The Mk V was a Jaguar-designed chassis with Standard engine - a shortened version of the chassis formed the basis of the XK120.
The XK120 did not set the world land speed record - at the time it stood to John Cobb's Napier Railton at close to 400mph. Great car it might have been, but the XK was never that quick!
 
Roger, I stand corrected (but it still made a good story). The Belgium event did not set the world speed record as I stated but served to clock the prototype XK120 at 132 MPH. Production models easily achieved 120MPH. I have heard of some talk that it was a record for production cars but I am not sure of that. Also the prewar designations all tended to be based on displacement in liters and had the SS in front. The immediate period after the war produced a pre war design of a one and a half liter sedan that is now called the Mark IV. Jaguar literature did not use the Mk IV. The first car to be a Mark officially was the V which was a total redesign with a 3.5 liter engine of push rod valve design. With the event of the XK engine in the sedan the designation became Mark VII with extensive styling changes. I dont know why VI was passed over. It is now late afternoon and I tend to be more accurate than when my last submission was written late at night. /ubbthreads/images/graemlins/cheers.gif Thanks for your correction. Jack
 
Absolutely - which is what I was hinting at in my first post! Rumour had it they were upset about the Mark V, which looked very Bentley-ish.
 
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