Overview

Spec	Value
Production Years	1968-1992
Body Styles	4-door saloon (standard wheelbase and long wheelbase)
Engine(s)	2.8L XK I6, 4.2L XK I6, 5.3L V12
Displacement	2792cc (2.8), 4235cc (4.2), 5343cc (V12)
Power	140-285 bhp (depending on variant)
Torque	170-294 lb-ft (depending on variant)
Transmission	4-speed manual with overdrive, 3-speed automatic (BW66 or GM TH400), 4-speed automatic (ZF, late cars)
Drive	Rear-wheel drive
Suspension (front)	Independent, double wishbones, coil springs, anti-roll bar, telescopic dampers
Suspension (rear)	Independent, lower wishbones, fixed-length driveshafts, coil springs, anti-roll bar
Brakes	Disc brakes all round, servo-assisted
Steering	Rack and pinion, power-assisted (standard on most models)
Construction	Steel monocoque with bolt-on subframes

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Series 1, 2.8L (1968-1973)

Spec	Value
Engine	2.8L XK DOHC inline-6
Displacement	2792cc
Bore x Stroke	83mm x 86mm
Compression Ratio	9.0:1
Fuel System	2x SU HD6 carburettors
Power	140 bhp @ 5500 rpm
Torque	170 lb-ft (230 Nm) @ 3750 rpm
Transmission	4-speed manual with overdrive or 3-speed BW66 automatic
0-100 km/h	~11.5 seconds
Top Speed	185 km/h (115 mph)
Fuel Economy	14-18 L/100km
Kerb Weight	1610 kg
Length	4899mm (SWB), 4999mm (LWB)
Width	1770mm
Height	1359mm
Wheelbase	2762mm (SWB), 2862mm (LWB)
Track (front/rear)	1461mm / 1461mm
Fuel Tank	82 litres
Tyres	205/70 VR 15 (E70 VR 15)

Note: The 2.8-litre is generally considered the least desirable XJ6 variant. Underpowered, rough-running, and prone to bottom-end problems. The 4.2 is the engine to have.

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Series 1, 4.2L (1968-1973)

Spec	Value
Engine	4.2L XK DOHC inline-6
Displacement	4235cc
Bore x Stroke	92.07mm x 106mm
Compression Ratio	9.0:1 (8.0:1 low compression option)
Fuel System	2x SU HD8 carburettors
Power	170 bhp @ 4500 rpm (net)
Torque	238 lb-ft (323 Nm) @ 3000 rpm
Transmission	4-speed manual with overdrive or 3-speed BW66 automatic
0-100 km/h	~8.5 seconds
Top Speed	195 km/h (121 mph)
Fuel Economy	14-18 L/100km
Kerb Weight	1660 kg (SWB), 1700 kg (LWB)
Length	4899mm (SWB), 4999mm (LWB)
Width	1770mm
Height	1359mm
Wheelbase	2762mm (SWB), 2862mm (LWB)
Track (front/rear)	1461mm / 1461mm
Fuel Tank	82 litres
Tyres	205/70 VR 15 (E70 VR 15)

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Series 1, V12 / XJ12 (1972-1973)

Spec	Value
Engine	5.3L SOHC V12
Displacement	5343cc
Bore x Stroke	90mm x 70mm
Compression Ratio	9.0:1
Fuel System	Lucas/Bosch fuel injection
Power	285 bhp @ 5500 rpm
Torque	294 lb-ft (399 Nm) @ 3500 rpm
Transmission	3-speed BW66 automatic (standard)
0-100 km/h	~7.5 seconds
Top Speed	225 km/h (140 mph)
Fuel Economy	20-26 L/100km
Kerb Weight	1800 kg
Length	4899mm (SWB), 4999mm (LWB)
Width	1770mm
Height	1359mm
Wheelbase	2762mm (SWB), 2862mm (LWB)
Track (front/rear)	1461mm / 1461mm
Fuel Tank	82 litres
Tyres	205/70 VR 15 (E70 VR 15)

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Series 2, 4.2L (1973-1979)

Spec	Value
Engine	4.2L XK DOHC inline-6
Displacement	4235cc
Bore x Stroke	92.07mm x 106mm
Compression Ratio	8.0:1 (some markets), 9.0:1
Fuel System	2x SU HIF7 carburettors (early) or Lucas fuel injection (later)
Power	170 bhp @ 4500 rpm (carb), 162 bhp (injected, some markets)
Torque	238 lb-ft (323 Nm) @ 3000 rpm
Transmission	3-speed BW66 automatic or GM TH400 automatic (later), manual rare
0-100 km/h	~9.0 seconds
Top Speed	190 km/h (118 mph)
Fuel Economy	14-19 L/100km
Kerb Weight	1710 kg (SWB), 1750 kg (LWB)
Length	4950mm (SWB), 5050mm (LWB)
Width	1770mm
Height	1370mm
Wheelbase	2762mm (SWB), 2862mm (LWB)
Track (front/rear)	1461mm / 1461mm
Fuel Tank	82 litres
Tyres	205/70 VR 15

Key Series 2 Changes

• Raised rubber-faced bumpers (US safety compliance)
• Enlarged grille
• Modified interior (safety regulations)
• Revised instrumentation
• Improved heating and ventilation
• Fuel injection on some markets
• GM TH400 automatic on later cars (replacing BW66)

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Series 2, V12 / XJ12 (1973-1979)

Spec	Value
Engine	5.3L SOHC V12
Displacement	5343cc
Bore x Stroke	90mm x 70mm
Compression Ratio	9.0:1 (7.8:1 US-spec)
Fuel System	Lucas/Bosch fuel injection
Power	285 bhp @ 5500 rpm (Euro), 244 bhp (US)
Torque	294 lb-ft (399 Nm) @ 3500 rpm
Transmission	3-speed BW66 or GM TH400 automatic
0-100 km/h	~7.8 seconds
Top Speed	225 km/h (140 mph)
Fuel Economy	20-26 L/100km
Kerb Weight	1870 kg
Length	4950mm (SWB), 5050mm (LWB)
Width	1770mm
Height	1370mm
Wheelbase	2762mm (SWB), 2862mm (LWB)
Fuel Tank	82 litres
Tyres	205/70 VR 15

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Series 3, 4.2L (1979-1992)

Spec	Value
Engine	4.2L XK DOHC inline-6
Displacement	4235cc
Bore x Stroke	92.07mm x 106mm
Compression Ratio	8.1:1
Fuel System	Lucas fuel injection (early) or Bosch fuel injection (later)
Power	163 bhp @ 4750 rpm
Torque	232 lb-ft (315 Nm) @ 2500 rpm
Transmission	3-speed GM TH400 automatic (standard), 4-speed ZF automatic (late cars), manual very rare
0-100 km/h	~9.5 seconds
Top Speed	195 km/h (121 mph)
Fuel Economy	14-18 L/100km
Kerb Weight	1740 kg (SWB), 1790 kg (LWB)
Length	4967mm (SWB), 5067mm (LWB)
Width	1770mm
Height	1378mm
Wheelbase	2762mm (SWB), 2862mm (LWB)
Track (front/rear)	1485mm / 1485mm
Fuel Tank	82 litres
Tyres	205/70 VR 15 (early), 215/70 VR 15 (later)

Key Series 3 Changes

• Pininfarina styling revisions (raised roofline, flush door handles, revised bumpers)
• Improved build quality throughout production
• Switch from Lucas to Bosch ignition (mid-production, significant reliability improvement)
• GM TH400 automatic standard
• Improved corrosion protection
• Sovereign trim level (extensive standard equipment)
• Revised instrumentation and switchgear

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Series 3, V12 HE / XJ12 (1981-1992)

Spec	Value
Engine	5.3L SOHC V12 HE (High Efficiency)
Displacement	5343cc
Bore x Stroke	90mm x 70mm
Compression Ratio	12.5:1
Fuel System	Lucas digital fuel injection
Power	299 bhp @ 5500 rpm
Torque	318 lb-ft (431 Nm) @ 3000 rpm
Transmission	3-speed GM TH400 automatic
0-100 km/h	~7.5 seconds
Top Speed	238 km/h (148 mph)
Fuel Economy	16-22 L/100km
Kerb Weight	1870 kg
Length	5067mm (LWB only)
Width	1770mm
Height	1378mm
Wheelbase	2862mm (LWB only)
Track (front/rear)	1485mm / 1485mm
Fuel Tank	82 litres
Tyres	215/70 VR 15

Note: The Series 3 V12 was offered only in long wheelbase form. Badged as XJ12, Sovereign V12, or Daimler Double Six depending on trim level.

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Engine Variants

2.8L XK DOHC Inline-6

A de-stroked version of the 4.2, offered as a budget entry point on Series 1 and early Series 2 cars. Reduced capacity created balance issues and increased stress on the bottom end. Underpowered in the heavy XJ body. The 2.8 is universally considered the weakest XJ6 engine option and best avoided. Many have been replaced with 4.2 units over the years.

4.2L XK DOHC Inline-6

The definitive XJ6 engine. The XK twin-cam six in its most developed road-going form. Not the most powerful version (the E-Type tune made more horsepower), but optimised for low-speed torque and smooth power delivery that suited the XJ6's touring character. The 4.2 is flexible, refined, and long-lived, 200,000+ km is routine with proper maintenance. Oil leaks are endemic but manageable. Carburetted cars (Series 1, early Series 2) are simpler but need regular tuning. Fuel-injected cars (late Series 2, all Series 3) are more refined but have their own diagnostic challenges.

5.3L SOHC V12

The same V12 as the E-Type Series 3 and XJ-S. In XJ6 application, it creates the smoothest luxury saloon available at any price. Pre-HE versions (1972-1981) are spectacularly thirsty. The HE version (1981 onwards) is more practical while retaining all the mechanical refinement. The V12 requires meticulous cooling system maintenance and more frequent attention to ignition components. Running costs are 40-60% higher than the six-cylinder.

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Transmission Options

4-speed manual with overdrive

Offered on six-cylinder cars only. Rare, particularly in Australia. Adds driver engagement but the XJ6's character suits the automatic better. The manual gearbox itself is robust. Overdrive is electrically engaged and works on third and fourth gears.

Borg-Warner BW66, 3-speed automatic (early cars)

The original automatic. Adequate but unreliable by modern standards. The BW66 copes with the six-cylinder but struggles with the V12's torque. Many have been replaced with GM TH400 units. If the car still has a BW66, budget for a potential conversion.

GM Turbo-Hydramatic 400 (TH400), 3-speed automatic

The standard automatic on later Series 2 and all Series 3 models. Virtually indestructible, same unit used in American trucks and rated for far more torque than any XJ6 engine produces. Smooth, strong, reliable. Change the fluid every 40,000 km and it'll outlast the car.

ZF 4-speed automatic (very late Series 3)

Fitted to the final production Series 3 models. Adds a fourth ratio for improved cruising refinement and economy. Less common than the TH400 but equally reliable.

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Trim Levels and Badges

Badge	Description
Jaguar XJ6	Standard six-cylinder model. Well-equipped but not fully loaded.
Jaguar Sovereign	Premium six-cylinder. Full leather, wood, electric seats, comprehensive equipment.
Jaguar XJ12	V12 engine, Jaguar grille.
Jaguar Sovereign V12	V12 with Sovereign luxury trim.
Daimler Sovereign	Six-cylinder with Daimler fluted grille, higher trim.
Daimler Double Six	V12 with Daimler badge. Top of the range.
Daimler Vanden Plas	Highest luxury specification (some markets). Extended equipment list.

All variants share the same basic structure, suspension, and running gear. The differences are trim, badges, and equipment levels. Daimler-badged cars command modest premiums but are mechanically identical to their Jaguar equivalents.

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Production Numbers (approximate)

Variant	Numbers Built
Series 1 (all, including XJ12)	~83,000
Series 2 (all, including XJ12)	~91,000
Series 3 (all, including XJ12)	~132,000
Total (all variants)	~306,000

The XJ6 was Jaguar's most commercially successful model, with the Series 3 accounting for the largest production run due to its 13-year lifespan.

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Notable Features

• Ride quality: The XJ6's defining characteristic. The combination of sophisticated independent suspension, carefully tuned damping, and compliant bushes created a ride that embarrassed Mercedes-Benz and BMW. Nothing else in the price range came close. Even today, a well-sorted XJ6 rides better than many modern luxury cars.
• Independent rear suspension: Derived from the E-Type system, lower wishbones, fixed-length driveshafts as upper links, coil springs, and an anti-roll bar. Complex but effective. The same basic design was used across the entire Jaguar range.
• XK engine lineage: The 4.2-litre XK six is one of the longest-serving and most celebrated engines in automotive history. Designed in the 1940s, race-proven at Le Mans, and refined across four decades of production.
• William Lyons's final design: The XJ6 was the last car personally styled by Sir William Lyons, Jaguar's founder. It's arguably his finest work, a car that combined elegance, proportion, and visual drama more successfully than anything else in the luxury saloon market.
• Dual-badge strategy: The practice of selling the same car under both Jaguar and Daimler badges maximised market coverage with minimal additional investment. It continued a tradition dating back to Jaguar's acquisition of Daimler in 1960.