Jaguar 420 / Daimler Sovereign 1966 - 1969

From Wikipedia, the free encyclopedia

Jaguar 420 / Daimler Sovereign (1966-69)
Manufacturer	Jaguar Cars
Production	1966–1968 Jaguar 420 - 10,236 1966–1969 Daimler Sovereign - 5,824
Successor	Jaguar XJ6
Class	Sports saloon
Body style(s)	4-door saloon
Layout	FR layout
Engine(s)	4.2 L XK I6
Transmission(s)	4-speed manual (Jag only); 4-speed manual/overdrive; or 3-speed automatic options available
Wheelbase	2737 mm (108 in)
Length	4762 mm (187 in)
Width	1702 mm (67 in)
Height	1429 mm (56 in)
Curb weight	1676 kg (3695 lb)
Related	Jaguar Mark 2 Jaguar Mark X Jaguar S-Type

Contents 1 Pedigree 2 Progress 3 Performance 4 Daimler 5 Differentiation 6 Demise

[edit] Pedigree

The Jaguar 420 (say it "Four-Twenty") and its Daimler Sovereign equivalent were produced for a short period at the end of the 1960s as the ultimate expression of a series of “compact sporting saloons” offered by Jaguar throughout that decade.

The Jaguar Mark 2 was introduced in 1959 and sold throughout most of the 1960s. It had a live rear axle and was powered by the XK six-cylinder engine first used in the Jaguar XK120 of 1948. In the Mark 2 the engine was available in 2.4, 3.4 and 3.8 litre capacities.

In 1961 Jaguar launched two new models. The Jaguar Mark X (say it “Mark 10”) saloon used a new independent rear suspension and a triple carburettor version of the 3.8 litre XK engine. The other new car for 1961 was the Jaguar E-Type sports car, which shared the same 3.8 litre engine as the Mark X and used a scaled down version of the independent rear suspension. In 1965 both cars were updated with a new 4.2 litre version of the XK engine, again with triple carburettors.

Meanwhile, in 1963 Jaguar had introduced the Jaguar S-Type as a development of the Mark 2, in which a mid-scale version of the Mark X independent rear suspension replaced the Mark 2’s live rear axle. Other differences the S-Type had over the Mark 2 were extended rear bodywork to provide for a larger boot, a changed roofline for more headroom, a slightly plusher interior and detail differences around the nose. The S-Type was available with either 3.4 or 3.8 litre XK engines (only 3.8 litre in USA) but in twin carburettor form because the triple carburettor setup would not fit into what was essentially still the Mark 2 engine bay.

In August 1966, Jaguar added to this range a new saloon that combined the 4.2 litre powerplant of the Mark X and E-Type with the compact body and independent rear suspension of the S-Type. This was the Jaguar 420, and its Daimler Sovereign equivalent was released at the same time.

[edit] Progress

Both new cars featured a squared-off nose with four headlamps to improve aesthetic balance compared with the S-Type and create a family resemblance to the Mark X. The 4.2 litre engine was slightly detuned (by 20bhp) compared with the Mark X and E-Type and carried just two carburettors. Ref. 1 suggests that this was due to a wish by Jaguar to avoid stealing sales from the more powerful Mark X but power-to-weight considerations would seem to give the lie to this.

Other mechanical refinements the 420/Sovereign had over the S-Type included:
• a larger and more efficient cross-flow radiator,
• an alternator in place of the dynamo,
• a pre-engaged starter,
• a viscous coupled engine cooling fan,
• replacement of the type 35 Borg Warner automatic transmission with the more robust Model 8,
• Adwest Marles Varamatic variable ratio power steering (an option on the Jaguar but standard on the Daimler),
• revised brake discs featuring a peripheral cast-iron vibration damper to prevent squealing.

Interior changes seem to have been driven mainly by safety considerations, with the wood cappings on the doors and dashboard being replaced by padded Rexine and only a wooden garnish rail remaining on the tops of the door linings. The adoption of an electric tachometer meant that the cabin clock had to be moved elsewhere, so it was relocated to the centre of the dashboard top rail.

[edit] Performance

Contemporary road tests indicate that the performance of the 420 and Sovereign was very highly thought of. For example, a Motor (UK) road test in May 1967 reported: ‘It seems somehow insolent to apply medium [price] standards to a saloon that for a combination of speed, comfort and safety is as good as any in the world, regardless of cost’. Similarly, a road test by Wheels (Australia) in August 1967 enthused: ‘While they can continue to build and sell cars as good as this, there is hope for the man who cares about his motoring’.

In terms of performance measured under test conditions, 0–60mph in under 10 seconds and a top speed of over 125mph were typical. The factory-quoted horsepower rating of 245bhp was often referred to as being rather optimistic, with the consensus being that about 180bhp was more realistic. Among the few exceptions the testers took was to the 16mpg fuel consumption, which even for the late 1960s was rather high.

[edit] Daimler

The ways in which the Daimler Sovereign was differentiated from the Jaguar 420 were few. Whereas the Daimler 2½ litre V8 of 1962 differed from the Jaguar Mark 2 by having a genuine Daimler engine, the Sovereign differed from the 420 only in its badging and aspects of interior trim. The Daimler differed from the Jaguar in having:

• a fluted Daimler-badged grille,
• wheel trim centres, horn button, oil filler cap and seat belt clasps carrying the flying ‘D’ rather than a Jaguar’s head,
• ribbed cam covers bearing the inscription ‘Daimler’ rather than ‘Jaguar’, (although the earlier versions shared the same polished alloy cam covers),
• higher grade seat leather with perforated centre sections,
• better quality covers for the sun visors,
• arguably more carefully selected and matched walnut veneer trim,
• all of the 420 extras as standard, including overdrive on manual transmission cars and power assisted steering,
• ref.1 also asserts that the Daimler had a fluted surround for the rear number plate lamps but inspection reveals this to be incorrect, or at least not universal.

[edit] Differentiation

A major reason the Jaguar 420 is less well known than other Jaguars is that relatively few were made. The factory at Browns Lane, Coventry, stopped making the 420 just over two years after production began and with only 10,236 produced. The Daimler Sovereign continued into 1969, by which time just 5,824 had been sold.

Another factor that makes the 420/Sovereign less familiar to enthusiasts and the general public alike is confusion over its nomenclature. At the same time as the 420 and Sovereign were released, Jaguar added more chrome to the Mark X and renamed it '420G' (for Grand). Then, in 1968, the 420G floorpan was modified to form the basis of the huge Daimler DS420 limousine.

[edit] Demise

By the end of the 420/Sovereign production run, buyers were hanging back to wait for the new Jaguar XJ6. Introduced late in 1968, the XJ6 was slightly larger than the 420 and swept it from the Jaguar range along with the Mark 2 and S-type. The Jaguar 420 ceased production at the end of December 1968 and the Daimler Sovereign in July 1969, although the Daimler version of the XJ6 retained the model name "Sovereign".

---

Jaguar 420	Daimler Sovereign	Jaguar 420 (foreground) Daimler Sovereign (background)	Jaguar 420 engine bay
Daimler Sovereign engine bay	Jaguar 420 interior (front)	Jaguar 420 dashboard	Jaguar 420 interior (rear)

---

Further Specifications

Engine	Jaguar 6 cylinder in line, iron block, alloy head
Capacity	4235cc
Bore/Stroke	92.07mm x 106mm
Valves	DOHC 2 valves per cylinder
Compression Ratio	8:1 (7:1 and 9:1 optional)
Max. Power	245bhp (183kW) @ 5500rpm [180bhp is thought to be more realistic]
Max. Torque	283lb-ft (384Nm) @ 3750rpm
Carburettors	Twin SU HD8 (2in)
Suspension	Front independent, with wishbones, coil springs with telescopic dampers and anti-roll bar Rear independent, with lower wishbone and driveshaft as upper link, radius arms and twin coil springs with telescopic dampers
Steering	Recirculating ball, worm and nut; Varamatic power assistance optional on Jaguar (standard on Daimler)
Brakes	Servo assisted discs on all four wheels, inboard at rear
Body/Chassis	Monocoque bodyshell with bolted front subframe, five seater saloon, front engine rear wheel drive
Tyres/Wheels	6.40 x 15 crossply or 185 x 15 radial, 5.5in rim, five-stud disc wheels with wire spoke optional
Track	Front=1410 mm (56 in) Rear=1384 mm (54 in)

---

References:
1. "Jaguar S Type and 420 – The Complete Story" by James Taylor, Crowood ISBN 1-85223-989-1
2. "Jaguar S Type & 420 – 'Road Test' Limited Edition", Brooklands Books ISBN 1-85520-3456
3. "Jaguar 420 Service Manual", Jaguar Cars Limited ISBN 1-85520-171-2