Jaguar XK140 restoration

31 October, 2021

This is a 66-year-old 3.4 Jaguar XK140 Fixed Head Coupe (FHC) powered by the XK double-overhead-camshaft six-cylinder petrol engine fed by a twin SU carburettor with a four-speed manual transmission.

It was produced at the Jaguar Browns Lane Plant in Coventry and first registered on 13th October 1955.

The Browns Lane plant was built by Daimler as one of the many British government shadow factories.

The shadow factories were built alongside existing motor industry factories in the build-up to WW2.
The idea was to accelerate the transfer of technology from high production motor industries to the new factories that would be building military vehicles and aircraft should war break out.

The factories were actually shown as an example of Britain's wartime readiness and capability. In the event, both the shadow factories and car production plants were all devoted to wartime production.

However, it was the XK140’s predecessor, the XK120, so-called for its top speed, an open two-seater concept car unveiled alongside the new luxury 4 door saloon Jaguar MK V  at the 1948 International London Motor Show that caused a sensation that reverberated worldwide.

The Jaguar XK120 (1948 - 1954)

The Jaguar XK120 (1948 - 1954)Jaguar XK120 OTS with a 3.4 litre 6-cylinder engine, this model built in 1954

The Catalyst

The Jaguar XK120 was pivotal in setting the Jaguar marque on the path to international renown not only as a prestige manufacturer of luxury saloons and sports cars but also of innovative engineering, as demonstrated by the longevity of the XK engine.

With versions ranging from 2.4 to 4.2 litre the XK engine would still be in production forty-four years later and power, perhaps the most iconic car of all time, the E-Type Jaguar, along the way.

But in 1948, times were challenging for manufacturers.


Jaguar E-Type 4.2 Litre Engine - The E-Type was produced 1961-1975Jaguar E-Type 4.2 Litre Engine - The E-Type was produced 1961-1975

The Debut at the 1948 International London Motor Show in October was a big deal and not just for Jaguar Cars.

Before the war the Jaguar name was associated with the model of the car, first used in 1935 as a model name on an SS 2½-litre sports saloon.

The company at that time was called SS Cars Ltd as listed in the 1938 motor show catalogue.

In 1945 the name was changed to Jaguar Cars Ltd to avoid any connotations or as William Lyons, the chairman of the company put it;

"Unlike S. S. the name Jaguar is distinctive and cannot be connected or confused with any similar foreign name”


It was the first opportunity to showcase in the UK in 10 years

Held annually since 1903 it was the 33rd International London Motor show, with interruptions by the first and second World Wars of 4 and then most recently 10 years.

In 1946 and 1947 the Paris motor show had been held, but until 1948 there had been a virtual ban on private motoring in France as well as Britain.

In 1948, three years after the end of the war, not only was petrol rationing (90 mile allowance per month) still in place, but would continue to be so until May 26th 1950.

As recently as the June of 1948, Parliament had passed the Motor Spirit (Regulation) Act, adding red dye to commercial petrol with closure being the consequence for vendors who abused it and a 12-month license suspension for private drivers who knowingly purchased it.  

Britain had emerged from the war with an empty treasury and had borrowed heavily to get back on its feet. 

The Ministry of Supply controlled the allocation of steel with a core focus on reducing the national debt by driving exports. 

A 1947 review of the British Motor Industry as part of a World Trade in Commodities report by M. A Colebrook of the United States Embassy in London, stated that "steel was the greatest raw material shortage facing the British motor Industry getting some 520,000 tonnes annually compared to 800,000 pre-war".

In the same year however that steel quota allocation by the Ministry of Supply was cut by 23 percent for a three month period.

A parliamentary exchange in February of 1948 included "that small quantities of steel strapping are being exported in order to maintain our imports of foodstuffs and raw materials." such was the parlous state of postwar Britain.

Manufacturers could not meet demand at home nor the all-important demand in the export field vital in creating foreign exchange.


Record Attendance

Held at Earls Court, London between 27 October – 6 November 1948 the show attracted 562,954 visitors.

Up by nearly a quarter of a million visitors on the previous highest attendance.


1948 Jaguar Mark V available as a 2½ and 3½ Litre.  Photo credit Jaguar Mark V available as a 2½ and 3½ Litre. Photo credit

Jaguar Mark V Luxury Saloon

The 4-speed Jaguar Mk V  had 5 seats available as a four-door saloon and a two-door convertible powered by the 1946-48 driveline including the overhead-valve pushrod straight 6, 2½L and 3½L engines.

It was specifically designed to be manufactured with left or right-hand drive for the export market and though a first for a Jaguar, was playing catchup with the competition by adopting hydraulic brakes. It introduced independent front suspension to the Jaguar range as well as flashing indicator lights, sealed headlamps, disc-type wheels and spats.


Jaguar XK120 Open Two Seater (OTS) first produced in 1948 Jaguar XK120 Open Two Seater (OTS) first produced in 1948

Jaguar XK120 - 3.4 litre 6 Cylinder

The XK120 was a prototype designed to promote the unveiling of Jaguar's brand new feat of engineering that was the twin-cam 3.4 litre 6-cylinder engine.

Originally planned to be launched in Jaguar's new range of saloons, the engine was ready, but luckily (as it turned out) the saloons were not.
Bill Lyons and his team decided to build a limited production sports car using a modified MK V saloon chassis fitted with the XK 3.4 engine.
The resulting XK120 prototype, ready in time for the London Motor show, consisted of a wooden ash frame with aluminium panels.


Competition for Home and Export Markets, as well as for Steel

There were 49 car production companies exhibiting their cars at the show and the Jaguar Mark V and the XK120 were competing for the home and American export market, but the event was also being used as a platform to launch the following 16 cars for the first time to the public:

  • Aston Martin 2-Litre Sports - the DB1 went on to sell 15 in total
  • Austin A70 Hampshire
  • Austin A90 Atlantic - targeting the American market
  • Hillman Minx Mark IV
  • Humber Hawk Mark III - production 10,040 from 1948-1954
  • Lagonda 2.6 -  With the new straight-6 engine 
  • Morris Minor - Between 1948 and 1972 1.6 million would be manufactured
  • Morris Oxford MO - 159,960 produced 1948 - 54, the Oxford Traveller appeared in 1952.
  • Morris Six MS
  • Singer SM1500
  • Sunbeam-Talbot 80
  • Sunbeam-Talbot 90
  • Vauxhall Velox
  • Vauxhall Wyvern
  • Wolseley 4/50
  • Wolseley 6/80


Motor Industry Suppliers

In addition to the 49 car companies, there were:

21 Carriage Work companies
243 Accessories and Components companies
50 motorboat companies
75 Transport Equipment Companies
20 Caravan and Light Trailer companies
11 associations ranging from the “Motor and Cycle Trades Benevolent Fund” to the “Junior Car Club” to the “Royal Automobile Club.


Jaguar XK120 3.4 Litre FHC next to a Jaguar E-Type 4.2 Jaguar XK120 3.4 Litre FHC next to a Jaguar E-Type 4.2

The Fastest Car In The World

In the early 30s, SS Cars Ltd had been producing beautiful looking sports cars, the  SS1and SS2 and the SS 90 in 1934 that looked the part but were described by some as “more show than go”

The company's response to its critics was the Jaguar SS100 launched in 1936.

SS Cars Ltd replaced the SS90 70bhp 2½-litre side-valve engine with a 2½-litre overhead-valve design that produced 102 bhp.
The Jaguar SS 100 was considered to be one of the most attractive cars of its era and is much sought after by collectors today.

The 2½-litre engine showed a top speed of 95mph, but a 3½-litre crossed the all important 100 threshold delivering 101mph.

Twelve years later the XK120 OTS stole the show and had plenty of go.

Twelve years later the XK120 Open Two Seater would not be found wanting. Not only was it stylish and an instant hit with celebrities (Clark Gable took delivery of the very first production car), it was also the fastest production car in the world, demonstrating innovative engineering and delivering a performance normally associated with cars costing twice as much

The "120" in the name referred to the wood-framed aluminium panelled car's 120 mph top speed.

With the combined assets of two brand new models on display, an open-topped sports car and a luxury saloon with a hint of Bentley about it, Jaguar covered a lot of ground in respect of design, carriage work, mechanical engineering and the introduction of a brand new engine.

The XK120’s rapturous reception prompted William Lyons, the Jaguar founder and chairman to put it into production without delay.

The initial XK120 production run consisted of aluminium panels over an ash frame.

In May 1950 the much-needed moulds for the non-opening body panels arrived allowing production to switch to pressed-steel bodies and rapidly increasing the monthly output.

The doors, boot lid and the top continued to be produced in aluminium, but the adoption of pressed steel body added 51kg (112Lbs) to the weight of the car.


The Jaguar Mark V - Outshone But Not Outsold

Though the XK120 was the star of the motor show and production went on until 1954 the Jaguar Mark 5 was no slouch in the sales department.

Offered as a four-door Saloon and a two-door convertible (Drop Head Coupe) it had a three-year production run of 10,495 vehicles from 1948 to 1951 until it was succeeded by the Jaguar Mark VII.

The Jaguar Mark 5 production of Left Hand Drive (LHD) to Right Hand Drive (RHD) split was 2680 / 7815,  just over 25% produced for export.

By contrast, the Jaguar XK120 had a six-year production run from 1948 to 1954 of 12,055 vehicles until it was succeeded by the Jaguar XK140.

The LHD to RHD split was 10392 / 1663

Of note is that over 86% of Jaguar XK120 were LHD and destined for export (mainly the American market).

The Flying Mile

The international standard for attempting to set a speed record is by entering the measured mile after attaining the highest speed possible.

In 1949 on a closed stretch of road In Belgium between Jabbeke and Aalter the press witnessed a left-hand drive XK120, only the second one produced in fact, achieve 126.448 mph.

After reducing the drag on the car by removing the hood, side screens, and windscreen and fitting a metal airflow deflector in front of the driver, and a tonneau cover on the passenger side the speed timed by the Royal Automobile Club of Belgium improved to 132.596 mph.

The car went on to record not only top speeds but endurance records including a 1952 XK120 fixed-head coupe being driven for a week averaging 100 mph.


A 1948 Jaguar XK120 with a 3.4 litre 6-cylinder engineA 1948 Jaguar XK120 with a 3.4 litre 6-cylinder engine

Competitive Sporting Accolades

The first competitive win for the XK20 was at a One-Hour Production Car Race at Silverstone in 1949.

1950 saw the Xk120 winning the 1950 production class in a race at Palm Beach Shores, Florida and a victory in the Pebble Beach Cup, followed by positive performances at the 24hrs Le Mans, Targa Florio, and outright wins and the team prize trophies at Silverstone production car race and the TT at Dundrod with Stirling Moss taking the chequered flag the day before his 21st birthday.

The coveted “Coup des Alpes” made the 1950 Alpine Rally win all the sweeter followed up with a win at the 51" rally as well.

The XK 120 C (known as C-type) designed by aeronautics engineer Malcolm Sayer went on to win at Le Mans in 1951 and 1953 and his sleeker D-type design running the same engine won the 24 hr Le Mans in 1955, 1956, and 1957.


Jaguar XK140 with "Winner Le Mans 1951–3" Badge Jaguar XK140 with "Winner Le Mans 1951–3" Badge

The XK120 was succeeded in 1954 by the XK140 which had big shoes to fill.

For the uninitiated the boot prominently sported a “Winner Le Mans 1951–3” badge and the marketing literature accentuating the pedigree with:

“All the accumulated wealth of knowledge and experience gained in the hard school of racing have been built into the new XK140 models which are powered by the famous 3½ litre twin overhead camshaft XK engine.”

The XK140 was a commercial success drawing on the 120’s sporting pedigree, whilst not actually racing. The C-type engine was flying the flag and the D type beckoned on the horizon, but it had nothing to apologise for.

The standard XK140 3.4 litre engine was more powerful, inheriting the Special Equipment “SE”  modifications applied to the XK120 which increased the bhp from 160 to 180. You could also opt for the C-Type cylinder head that would produce 210bhp.


The Jaguar XK140

The Jaguar XK140 The Jaguar XK140 produced 1954–1957 and then succeeded by the XK150

When compared to the XK120, the XK140 exterior changes were subtle but identifiable.
It had larger chrome bumpers on the front and the rear.

The grill had fewer bars flowing down from the embedded XK140 Coventry England Jaguar badge.

Front turn signals featured on top of the fenders and amber driving lights were positioned just above the bumpers. 

Available once again as an Open Two Seater (OTS), a Drop Head Coupe (DHC), and a Fixed Head Coupe (FHC), the XK140 also featured a Laycock de Normanville overdrive.

If you didn't want to go to all the trouble of changing gears you could opt for the Borg-Warner automatic gearbox on the DHC or FHC models.

A new rack and pinion system improved steering, and passengers experienced a smoother ride helped by introducing rear telescopic shock absorbers.

Extra Legroom in Jaguar's XK140 luxury sports car

Extra Legroom in Jaguar's XK140 luxury sports carExtra Legroom

The engine and dashboard were moved forward by 3 inches allowing that extra legroom.

This allowed more space for the occasional seats in the Hardtop and Drophead Coupe convertible models and allowing occupants of over 6 feet in height, something impossible for the XK120.

A modest change, but a big difference.

Time for a proper examination of our XK140 restoration project

Time for a proper examination of our XK140 restoration project

Jaguar XK140 - Restoration Tasks

When we got the XK140 back to the workshop, as is to be expected, several years of inactivity had not been kind. 

The paintwork had received unwanted storage damage, moths had eaten the carpets, the tyres perished, the brakes had seized up and the car was not running.

So there was quite a bit of work to do.

We cleaned the fuel tank and replaced the petrol pump and pipework that was not resistant to ethanol ( E5 has 5% ethanol and E10 - 10% Ethanol )

A whole box of brake parts were fitted including the rear brake shoes that had to be relined.

The clutch cylinders were also seized and needed to be replaced.

We changed the gearbox and rear axle oil, new ignition system, and rebuilt the carburettor including the linkage.


All the interior was removed, a new carpet set fitted and correct moquette material was used on the back of the seats and inside the boot.

The paintwork was addressed by a Jaguar marque specialist.
Following weeks of detailing including the engine bay and the underside of the car, it was back to factory fresh.

A rewarding restoration of an Iconic British Classic Car

Following weeks of detailing including the engine bay and the underside of the car, it was back indeed back to factory fresh, the smell of new carpet, a throaty engine, and an absolute delight to drive an iconic luxury sports classic with an unparalleled pedigree.

The XK140 was the second car of a successful and uninterrupted run, which also spawned the XK150 (1954–57), XK150 (1957–61), and the E-Type (1961-75) and the ongoing use of the XK engine through to 1992.