The Jaguar XK100 and XK120

Years 1948-54 (XK120)       
See also Jaguar XK140
Jaguar XK150
Notes The XK100 never existed as a production model, but there had been  plans to produce it, and it was to have been powered by a 2 litre 4 cylinder engine which had been developed as part of the engine development program that had taken place in the war years. Apart from the engine, the car itself was to have been much the same as the XK120. It was never produced because  the cost would have been almost the same as the XK120 due to the fact that initially the cars were largely handbuilt and this accounted for the largest percentage of the total cost. .

The XK120 itself was almost certainly never intended to be a volume production model either. At that time Jaguar had an engine - the newly developed 6 cylinder XK unit, but the large sedan for which it was intended was not ready. This car, the MK VII finally appeared in 1950. In the meantime Jaguar badly needed to stir up some excitement, as its range was still of pre-war design, so the XK Open Two Seater Super Sports as it was then known was designed as a "show car" for the 1948 Motor Show. It utilized a shortened version of the chassis designed for the MK VII, which was already in use in the post war MK V, and the brand new XK engine, the result of all the research done during the war, while Jaguar could not produce any cars. It made extensive use of aluminum for the body panels, and William Lyons had plans to market it as a fairly low volume "specialty car". Its purpose was to maintain public interest until the introduction of the MK VII, and act as a test bed for the new engine.

The rest is now history, the car was a sensation, and orders so overwhelmed the production capability that it had to be redesigned with a metal, rather than an aluminum body, so that it could be produced on a production line, rather than largely handbuilt as the prototype and the first 239 cars were. Because of the need to redesign and retool, volume production did not come onstream until 1950.  Despite all the work done to "productionize" the car, the outward appearance did not change much at all - only some hard to spot panel curvatures reveal the difference.

Initially the car was called the XK Open Two Seater Super Sports, and was quickly renamed the XK120. The name derives from the engine and the top speed.  All the engines types made during the war were "X" for experimental, and the next letter was the sequence. "K" happened to be the sequence of the engine that was up to the job.

The first model came to be known as the XK120 Roadster in retrospect, after the introduction in 1951 of the Fixed Head Coupe (FHC), and in 1953 of the Drop Head Coupe (DHC). The Roadster featured a hood and sticks approach to weather protection, along with detachable side screens, whereas the DHC had a proper stowable hood, and wind up windows, along with all the extra luxury inside that the FHC featured. This included extensive use of wood in the dashboard and door cappings. The design of the roof on the FHC showed a strong family likeness to the, then brand new, Mk VII

This split of models into two open and one closed type was to persist over all three iterations of XK series sports cars until the introduction of the E-Type in 1961. (Note however the XK150 Roadster did feature wind-up windows)

Description 2 door sports, ultimately available in three body styles
  • Roadster or "OTS"
  • Drophead or "DHC" for "Drop Head Coupe"
  • Fixed Head Coupe or "FHC"
Colors See the XK models color details page
xk1201954OTS.jpg (38595 bytes)

This photo by kind permission :  Richard R. Smith, British Museum of Transportation
It shows a 1954 OTS model fitted with racing aero wind shield and painted wire wheels

Model Engine Bore/Stroke Power
XK100 1995cc 4 cyl twin overhead camshaft   95 bhp
XK120 3442cc 6 cyl twin overhead camshaft 83 x 106 mm 160 bhp @ 5000 rpm
3442cc 6 cyl twin overhead camshaft 83 x 106 mm 180 bhp @ 5000 rpm
210 bhp @ 5000 rpm
with "C" type head
XK120 Twin SU H6 (XK120), Twin SU H8 (XK120SE)
Engine was the first use of the Jaguar XK type DOHC inline 6.
Brakes 4 wheel hydraulic drum

(Various sources differ, slightly and these numbers are most vague for the FHC. Those numbers are accurate to around 80 cars)
No details are available on the split of numbers between RHD and LHD, but some sources do break out the numbers between home and export production. It is interesting to see what a small proportion of these cars was sold in the home market. At this time of austerity after the second world war, it was of vital importance to earn export currency, and demand for this car was high in export markets.....

No statistics seem to be available on how many cars were produced in SE trim

XK120 (aluminum)
All except 5 or 6 appear to have been exported.
XK120 Roadster
Home    609
Export   6765
Total 7614 (includes 240 aluminum body cars)
XK120 Fixed Head
Home 152
Export 2528 
Total 2680
XK120 Drop Head
Home 263
Export 1504
Total 1767
Total, all models 12061  
XK120 Roadster/DHC 2856 pounds
XK120 FHC 3024 pounds
Length 14 feet 5 inches
Height 4 feet 5 1/2 inches (Roadster 4 feet 4 1/2 inches) 
Width 5 feet 2 inches 
Top speed 120 mph (120 plus for SE model)
Wheelbase 102 inches
Transmission 4-speed manual. (Overdrive fitted on SE model)
Front Independent. Coil springs, double wishbones and anti-roll bar
Rear Live axle, semi elliptic leaf springs. Lever arm dampers..
Chassis Numbers
Additional codes with number
S prefix indicates Special Equipment model
Roadster 660001 and up (RHD models)
670001 and up  (LHD models)
Fixed Head 669001 and up (RHD models)
679001 and up (LHD models)
Drop Head 667001 and up (RHD models)
677001 and up (LHD models)
Engine Numbers See the Jaguar Engine numbers page
Standard Equipment Heater (after 1951), Leather seating on all models.
Options SE Model (known as XK120M in the USA)
gave power boost to 180bhp using high lift camshafts. Wire wheels and two foglights were fitted as standard,  as was overdrive. As an addition to the SE model an even more powerful 210 bhp engine was an option by fitting the "C" type cylinder head and larger 2 inch SU carburetors.

All models except where already fitted to SE
Wire wheels available after 1951 in body color or silver or chrome, Various radios, fog lights, Heater (standard after 1951), various radios, bucket seats, to replace standard bench seat. fitted luggage for trunk (boot), Luggage Rack.  Various accessories intended for the serious competition motorist were also available, such as aero screens on the Roadster, auxiliary fuel tanks, etc.

When steel wheels were fitted, spats were fitted in the rear wheel wells. These were omitted in cars equipped with steel wheels because of the extra width of the spinner. Wheels were all 16 inch, and wire wheels had54 spokes.

Replica Kits XK120 replicas using modern Ford mechanical parts are available from Eagle Coachwork