Guide: Jaguar XK140
Background
At the London Motor Show in October 1954, Jaguar unveiled an uprated version of the phenomenally successful XK120.
The revamped XK140 was improved in several ways. Most importantly, if offered more cockpit space compared to the somewhat cramped XK120. Jaguar also paid attention to the brakes, steering and suspension. A more powerful engine was fitted and a number of subtle body refinements were introduced as well.
The XK140 had big boots to fill as its predecessor had established itself as the most commercially successful high end sports car on the market.
The XK120 was originally unveiled at the 1948 London Motor Show. Jaguar displayed the car alongside their luxurious Mark V as a way to promote the firm’s new 3.4-litre dual overhead camshaft straight six engine. However, the XK120 stole the show and Jaguar boss, William Lyons, quickly decided to offer it to the public.
Production XK120s began to trickle out of the factory in June 1949.
Jaguar struggled to keep up with demand until May 1950, when the arrival of long-awaited moulds enabled them to switch from hand-made aluminium to pressed steel for the non-opening body panels.
By this time, the XK120 had begun to demonstrate its competition prowess. After a couple of strong early showings by production variants, Jaguar produced seven semi-works examples that were supplied to a number of privateers who were given considerable factory assistance.
Leslie Johnson finished fifth at the Mille Miglia and looked set for a potential win at Le Mans until clutch failure forced him to retire while lying third.
Elsewhere, Peter Walker won the Silverstone 1 Hour Production Car race (an event won by Leslie Johnson in 1949 on the XK120’s debut) and Ian Appleyard took victory on the Alpine Rally.
Stirling Moss won the Dundrod Tourist Trophy in Tommy Wisdom’s car. A number of international speed records were also achieved.
After the XK120’s promising display at the 1950 Le Mans 24 Hours, William Lyons sanctioned the development of a fully fledged sports racing version for 1951. The resultant XKC (better known as the C-type) made its debut at the 1951 Le Mans 24 Hours. Three works cars were entered; one retired, one finished eleventh and the example driven by Peter Walker / Peter Whitehead took a famous victory.
Thanks to the XK120 and C-type, Jaguar became a force to be reckoned with. Commercially they dramatically out-produced rival firms both domestic and foreign while, on track, they successfully took the fight to Enzo Ferrari’s burgeoning operation.
By the time XK120 production came to an end in late 1954, over 12,000 had been built. The overwhelming majority of these were manufactured for export to help with Britain’s Balance of Payments.
Like the XK120, the XK140 was offered in three body styles. The Open Two Seater (OTS or Roadster) was offered alongside the more luxuriously equipped Fixed Head Coupe (FHC) and Drop Head Coupe (DHC).
Chassis
Both the XK120 and XK140 were built on a box-type chassis which itself was a shortened, simplified and lightened version of the one used by the Mark V. The XK variants shared an identical 102-inch wheelbase, but in order to provide more legroom, the 140’s front bulkhead was moved 3-inches further forward.
To improve handling, the XK140 came with telescopic rear shock absorbers instead of lever arms. Suspension travel was also increased.
Otherwise, the layout was much the same as before. The independent front arrangement was via wishbones, torsion bars, telescopic dampers and an anti-roll bar. The live Salisbury rear axle was located with semi-elliptic leaf springs.
Rack-and-pinion steering replaced the outgoing Burmann recirculating ball arrangement.
12-inch Lockheed drum brakes were fitted all round along with 16 x 5.5-inch solid steel wheels and chromed hub caps. The rims were half-an-inch wider than those fitted to the XK120 and led to a commensurate expansion of the track dimensions.
Crossply Dunlop tyres were standard equipment while Pirelli Cinturato radials were an optional extra.
A 14 gallon (63.6-litre) fuel tank was installed over the rear axle.
The XK140 FHC adopted two 6-volt batteries in each front wing while the DHC and OTS used a single 12-volt battery in the passenger side front wing.
Engine / Gearbox
In the engine bay was the latest version of Jaguar’s William Heynes-designed straight six.
Arguably the most advanced mass produced power unit in circulation upon launch, it was still a venerable proposition six years down the line.
The engine featured a cast-iron block and aluminium alloy head with dual overhead camshafts, hemispherical combustion chambers and inclined valves. Wet-sump lubrication was employed along with single plug ignition and a Lucas coil.
Displacement was 3441cc thanks to a bore and stroke of 83mm and 106mm respectively.
Two SU H6 sidedraught carburettors were fitted and, for most markets, a compression ratio of 8.0:1 was adopted. In this configuration, peak output was 190bhp at 5500rpm and 210lb-ft at 2500rpm.
Transmission was via a Moss four-speed manual gearbox.
Special Equipment & Special Equipment with C-type Head Options
Jaguar additionally offered the Special Equipment pack and also the Special Equipment with C-type head.
The former included a crankshaft dampener, wire wheels, a dual exhaust, twin fog lamps, and windshield washers. It was known as the XK140 M in the USA.
The Special Equipment with C-type head came with two-inch sand-cast H8 carburettors, a big valve head, high lift camshafts, a 9.0:1 compression ratio, heavier torsion bars and twin exhausts. Peak output was 210bhp at 5750rpm and 213lb-ft at 4000rpm. This variant was marketed as the XK140 MC in America.
Bodywork
Cosmetically, the XK140 ushered in a number of changes compared to the outgoing XK120.
Most obviously new were bigger bumpers which now came with overriders. A full width bumper was fitted at the front and quarter bumpers were installed at the rear.
Longer doors made access to the cockpit easier and the windscreen was positioned further forward as per the new front bulkhead.
There was also new lighting: circular flashing turn signals were mounted above the front bumper and new tail lights were added out back.
The bonnet and boot lid were both given a decorative chrome trim strip down the centre. A new emblem in the middle of the boot trim strip read ‘Winner Le Mans 1951-3’.
Up front, the grille remained the same size as before, but was now cast in a single piece and the number of vertical bars was reduced from 13 to seven. It also now incorporated the Jaguar emblem whereas the XK120 had used a separate badge above the grille.
As per the XK120, three body styles were offered.
The pared down Open Two Seat Roadster came with cut-down doors, a simple canvas roof and detachable side screens. When removed, the roof and side screens could be stowed out of sight behind the seats. A tonneau cover was also supplied and the windscreen was still removable. The OTS Roadster had no exterior door handles so entry to the cockpit was by an interior pull-cord. When the weather gear was in place, the door pulls were accessed through a flap in the side screens.
The Drop Head Coupe came with a proper folding canvas roof that could be lowered onto the body. This variant came with a fixed windscreen and proper wind up side windows.
The Fixed Head Coupe was essentially a hard top version of the Drop Head.
Unless the optional wire wheels were specified, XK140s came with disc wheels and spats at the rear.
Interior
Aside from offering a little more interior space, cockpits were much as before.
Interior equipment included a four-spoke Bluemels steering wheel mounted on a telescopically adjustable column. Located in the centre of the dash was a rectangular binnacle which housed a large rev counter and speedometer plus smaller read outs for fuel, battery condition and a combined oil pressure / water temperature gauge.
Leather was used to upholster the dash, door panels, the seats, armrest and the handbrake and gear gaiters.
The FHC and DHC were broadly to the same specification; the latter came with a padded and lined canvas top while the roof on the FHC featured fine wool headlining.
The FHC and DHC both came with lockable doors. Inside, burr walnut veneers were applied to the dash, door caps and window surrounds. Wind up windows were fitted along with opening front and rear quarterlights. Other equipment included tinted Plexiglas sun visors and a lockable glovebox. New features included twin instead of single ashtrays and a pair of occasional rear seats.
Options
Jaguar offered an array of optional extras that enabled customers to add performance, safety and style.
In addition to the SE and SE with C-type head, buyers could separately specify a dual pipe exhaust system, a close-ratio gearbox, aero screens (OTS only), Dunlop racing tyres and bucket seats.
Those that wanted added practicality could request Lucas fog lamps, a steel underbody protective shield, windscreen washers and a chromed luggage rack for the boot lid.
Further personalisation could be had with wire wheels, Dunlop Road Speed tyres with whitewalls, a choice of Radiomobile audio equipment, a white instead of black Bluemels steering wheel and fitted luggage (two suitcases that matched the interior upholstery).
Weight / Performance
Jaguar quoted a weight of 1350kg for the OTS Roadster and 1420kg for the Fixed Head Coupe and Drop Head.
In standard trim, top speed was 125mph and 0-62mpg took 8.4 seconds.
Production Changes
During the course of production, myriad updates were phased in.
Among the more significant were a new rotor type oil pump, a circular oil seal at the front end of the crankshaft and deletion of the oil pressure valve from the filter head (all in February 1955).
In March 1955, a new thermostat was fitted. This was followed in September by a new lower timing chain tensioner. A modified cylinder head with reduced tapped hole depth arrived in December.
A new type of adjustable wing mirror was installed from March 1956. That October, the doors on FHC and DHC variants were switched from aluminium to steel.
From 1956, Jaguar began to offer a three-speed Borg Warner DG250 automatic gearbox.
Competition History
By the time XK140 production began, Jaguar’s factory racing activities had long since switched to out-and-out sports racing cars like the C and D-type. However, a number of enthusiastic amateurs were quick to take their XK140s to the track.
Over in the US, the likes of Charles Wallace, Jerry Austin, Dick Thompson and Harry Carter did well in SCCA C Production class racing.
Perhaps the most notable outing in a major race was a tenth place finish and second in class for Charles Wallace and Dick Thompson in an OTS Roadster at the 1955 Sebring 12 Hour World Sportscar Championship event.
One XK140 even made it to the Le Mans 24 Hours: Robert Waltshaw co-drive his FHC with Peter Bolton, but they were disqualified for an illegal refuel early on Sunday morning.
End of Production
XK140 series production took place from September 1954 to January 1957.
In total, 8937 XK140s were built.
Left-hand drive OTS production was from September 1954 to January 1957 while right-hand drive examples were manufactured from October 1954 to October 1956.
3349 OTS Roadsters were built, 73 of which were right-hand drive. VIN numbers ranged from 800001 to 800074 in right-hand drive and 810001 to 813282 in left-hand drive.
FHC production started in both left and right-hand drive in October 1954. Right-hand drive cars were discontinued in November 1956 and left-hand drive in January 1957.
In total, 2798 XK140s were built with FHC bodywork, 839 of which were right-hand drive. VIN numbers ranged from 804001 to 804843 in right-hand drive and 814001 to 815966 in left-hand drive.
DHC production began in October 1954 and lasted until January 1957 for both right and left-hand drive variants. 2790 were built in total (480 of which were right-hand drive). Right-hand drive VINs ranged from 807001 to 807480 and left-hand drive cars from 817001 to 819311.
Cars built to SE specification incorporated an ‘A’ chassis prefix and those that left the factory in SE specification complete with the C-type head used an ‘S’ chassis prefix.
Text copyright: Supercar Nostalgia
Photo copyright: Jaguar Heritage Trust - https://www.jaguarheritage.com/
