Monday 22nd July 2019,

Jaguar MKI 2.4 & 3.4 Sports Saloon 1955 – 1959

From the end of World War II Jaguar`s models got progressively bigger. Bill Lyons was pleased with the company`s success but yearned to return to building smaller, sportier cars. To fully understand the thinking it is necessary to look back in history.

High power-to-weight ratios were always the objective. Before the war cars were heavy and engines therefore big and heavy. Acceleration, braking, handling and economy suffered accordingly. Aviation development during the war was showing the way forward. Engine development had made good progress during the war, so had airframe design.

Cars at this time used a separate chassis frame consisting of two heavy `longerons` running front to back for the full length of the car. Cross-members were fitted at strategic points to hold the longerons rigidly in position and supply load-bearing carriers for the power-train. Short out-riggers were welded to the chassis going out to the extreme edges of the car to give the body fixing points. Floors were not load-bearing, usually made of wood. When put together this was known as a rolling chassis, a complete car without a body. Buses are still made this way and can often be seen driving from factory to body-builder. Bodies were made by `coach-builders` who fixed a framework to the chassis to build the body onto.

Pre-war this frame was usually made of wood. Body panels, if steel, tended to be thin guage because of the limitations of bending equipment. Hydraulic sheet-metal presses, refined in the aircraft industry in the war years offered a new construction method.

The new presses, with techniques developed in the war industries, allowed lighter chassis to be used because steel floor-pans and bulkheads could be made. Bulkheads had not been load-bearing before but now could be welded into a rigid body. With the new, lighter chassis members welded underneath a rigid, integrated body shell could be built, using pressed steel body panels to increase the strength. This is correctly known as Unitary Construction.

Many knowledgeable publications have referred to it as Monocoque. This is incorrect. A monocoque has no chassis, the bearers for powertrain and rear suspension are subframes bolted to the monocoque `tub`, rather like a Formula 1 car. The first Jaguar monocoques were the MK X and the E type.

This long digression (for which the author apologises) brings us back to the classic car, the MKI Jaguar.

Lyons reasoned that producing a 2.4 litre XK with smaller and lighter engine block was a good place to start. He decided to use unitary construction for the first time. This, added to reduced engine weight made for a very good sports saloon. The car was no bigger than it had to be and therefore was quite quick, being one of the few cars available that would do a genuine 100 mph.

It did, however, have one or two design problems. Narrow axle track which compromised the handling and poor brakes (discs had not yet arrived in the commercial cars). In 1957 however, disc brakes became optional as they proved reliable on the C-type. It was fitted with large, ungainly wheel-spats at the rear, though most owners discarded them. The car sold very well and was complimented by the 3.4 produced alongside in 1957. All the short-comings of the MK I were rectified by the MKII which followed it in 1959.

Jaguar MKI 1955-1959
Body Type5 seater 4 door saloon
Engine PlacementFront
Drive TypeRear wheel drive
FrontDrumsDiscs (1957 opt.)
RearDrumsDiscs (1957 opt.)
Cargo VolumeVery respectable
Engine2.4 Jaguar XK DOHC 12V Hemispherical
Cylindersstraight 6
Displacement2483 cc151.5 cui
Power84 Kw112 bhp5500 RPM
Torque195 Nm144 ft. lb2000 RPM
Power/weight82 bhp/t
Top Speed164 km/h102 mph
Acceleration0-100 km/h - 0-60 mph13.4 s
Fuel consumptionl/100 kmImperial mpg
Gearbox4 speed manual+Overdrive (opt)3 seep automatic
Weight1372 kg3025 lb
Engine3.4 Jaguar XK DOHC 12V Hemispherical
Cylindersstraight 6
Displacement3442 cc210 cui
Power157 Kw210 bhp5500 RPM
Torque291 Nm215 ft. lb2500 RPM
Power/weight153 bhp/t
Top Speed193 km/h120 mph
Acceleration0-100 km/h - 0-60 mph9.1 s
Fuel consumptionl/100 kmImperial mpg
Gearbox4 speed manual+Overdrive (opt)3 seep automatic
Weight1372 kg3025 lb
GD Star Rating
Jaguar MKI 2.4 & 3.4 Sports Saloon 1955 - 1959, 10.0 out of 10 based on 2 ratings
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About Bev Roberts

Speed, the smell of hot oil, the roar of a straight-through exhaust and the scream of an engine at max revolutions. They have all been a large part of my life for almost 50 years. It is time to share my experiences with you, dear reader. Do you want to know more? Read on through my `Full Bio` and many articles.

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I was born in Hereford UK in 1948 and brought up in Gloucester UK. I played Rugby football internationally as a schoolboy. At the age of 17, a new and wet driving license in my paw, I entered motor racing. I was supported and financed by my parents and so my journey began.

In 1965 I bought a 1293cc Mini-Cooper `S` and campaigned it for a season. Having quickly made some good friends in the racing fraternity, several interesting opportunities came my way. I joined a sports-car team and raced in the Le Mans 24 hours in 1968 and 1969 in a Lola T70. Mechanical failure defeated both efforts. During that period I owned and raced a `D type` Jaguar and an AC Cobra. In those days cars like that were available and not too expensive, now they reside in museums and private collections. I had a chain of interesting cars through my youth including Jaguars, Minis, Mustangs and Lotus-Cortinas.

As a young driver I had my share of accidents too. Often the car would only be worth scrap-metal value by the time I got it home! I worked for an Aston-Martin/Jaguar dealership for a while, which enhanced my experience and gave me the opportunity to sample some very exotic machines, Ferrari, Facel-Vega, Iso and Maserati to recall a few of them.

At the end of 1969 I moved to South Africa to work on my uncle`s farm but the S.A. government had other ideas and drafted me into the army. After five years had passed I was thanked and released from the service. While I was there I bought a beige Cadillac Eldorado, previously the property of Marilyn Monroe. While I was away on a patrol my girlfriend had it re-sprayed pink! I was unimpressed by both the joke and the bill for the work!

When I returned to UK in 1974 I left it behind. On my return I found that the once-mighty British motor industry was in decline and was headed for oblivion. Motor racing was now very expensive so I turned to commercial transport. Driving large trucks gave me freedom and a chance to see some of the world. I don`t remember ever making a career choice but for the next thirty years a truck was my home. For about ten years in that period I owned two trucks of my own.

I also owned a famous MGB-GT, known as `Lucky`. If you`d like to read `The Story of Lucky` there is an article in Inopian`s archive. I finally retired, due to ill-health, in 2008. Since I had varied knowledge and many experiences on our subject I decided to share the stories of the cars I enjoyed (and hated) with the new generation.

Enjoy Inopian… it is constructed and written for you.

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