MGB

….Clearly, then, the replacement for the MGA was originally intended to be a closed coupe. A new project was authorized, coded EX205, which would evolve through a number of designs over the next few years.

Designs were submitted, from MG’s Chief Body Engineer Jim O’Neill and Turin styling house Frua, based on the MGA’s chassis, but it was a similar concept from Don Hayter that was taken to the next level.

Hayter’s design for a coupe featured headlights recessed in cowls on either side of a modified MGA grille, and showed definite influences from Aston-Martin at the rear. That wasn’t too surprising, given Thornley’s previous comments about the Astons and Hayter’s background.

He had been apprenticed to the Pressed Steel company straight from school in 1942, at the height of the war, and was involved in the translation of engineering drawings for aircraft fuselages and tail sections.

After the war the company returned to car production and Hayter was involved with the Jaguar XK120 and the MG ZA Magnette – MG’s first unitary or monocoque design.

In 1953 he joined Aston Martin at Feltham, in London’s outer-West. His first job was the redesign of the DB3’s radiator, followed by conceptual sketches of the DB4 that were then translated by Touring of Milan.

David Brown, owner of Aston, bought the Tickford engineering firm in Newport Pagnell, near Milton Keynes, in 1956 and moved his company up there. Hayter didn’t want to go there so approached MG for a position and was appointed as Chief Body Draughtsman. One of his first tasks was to draw up a new bonnet for the MGA, which would fit the twin-cam engine.

When he came to his proposal for the MGA’s replacement he sought inspiration for the bonnet line and side profiles from the EX181, the front from Ferrari and the rear, as previously mentioned, from Aston.

Although the early emphasis had been on a closed coupe, it was fairly quickly decided that a roadster version of the car would be more in keeping with expectations from the marketplace for an MGA replacement – even though there had been an attractive MGA Coupe available from 1956, of which only around 10,000 were made across all models (about 10% of total production).

In designing a roadster version of the MGB, which by now had been allocated a new project code of EX214, Hayter decided to chop the sloping front off sharply and redraw the radiator grille. Farina-style fins were the fashion of the day – as already seen in the likes of the Austin A40 Farina, and Wolseley 15/60 & MG Magnette Mk111 series.

Originally, Hayter wanted larger tailfins on the ‘B’, but the need to keep the tooling as simple as practical and therefore to keep costs down, ensured the fins were kept small.

The overall concept behind the MGB was to take the best points of the MGA and provide elements that would be more acceptable to a wider audience, particularly in the US. This would mean making the suspension a lot less jarring on the occupants, improving the interior comfort and generally making the car more civilized, while maintaining the sporting looks and nature of the handling.

While development of the body shape had been going on, Syd Enever had come to the realisation that retaining the MGA’s separate chassis would make the car too heavy, when taking into consideration the extra weight of wind-up windows and larger doors.

Enever took the still rather novel approach, for a sports car at least, of designing the MGB as a monocoque. Although the MG ZA Magnette and the Sprite/Midget were monocoque designs, this was Enever’s first attempt at a chassis-less car. As John Thornley said in his foreword for MGB – The Illustrated History: “He got it right: so right that, although the car was intended for a production life of the customary five years or so, circumstances dictated that it went on and on, and was still outselling its competitors eighteen years later”.

Another key factor in the design was the engine. Originally it was proposed that the MGB would be powered by either a narrow V4 (2lt) or V6 (3lt), that was being worked on at Longbridge by Dr Duncan Stuart. However, because of the enormous tooling and set-up costs that would be required, the V-engine project was abandoned.

It was also considered to use the C-series 3lt six-cylinder engine of the Austin-Healey 3000, and Don Hayter actually designed the body of the MGB around that engine. Although that idea was dropped fairly quickly to avoid direct competition with the Healey, it explains why it was a fairly straightforward procedure when that engine was finally adopted for the MGC in 1967. Instead, the MGB would have to make do with the engine from the final version of the MGA. The B-series had originally been designed in 1200cc form by Austin for the A40 Dorset and Devon models of 1947. It had been progressively enlarged to reach 1489cc for the MGA and ZA Magnette. It was increased again to 1588cc for the MGA 1600 and to 1622cc for the MGA 1600 MkII.

Meanwhile, in 1960, BMC’s Leonard Lord had informed Donald Healey that an update for the Austin-Healey Sprite (the famous Bug Eye) was needed, and told him to redesign the front of the car. Unknown to Healey, he also instructed MG to redesign the rear end, to incorporate an opening bootlid. The intention was that the revised car would be available as both a Sprite (the MkII) and a new MG Midget.

MG’s contribution was by Dennis Williams, who apparently borrowed the design of the rear from Hayter’s MGB. Although the Midget is often referred to as the father of the MGB because of the earlier release, the similar style and that both are monocoque designs, it must be remembered that the body of the MGB had been completed before the Midget. The reason the Midget came out first, in 1961, was basically because it was a re-skin of a car already in production, while the MGB still had considerable development of suspension and drive-line to be completed.

The delay with the B’s suspension was due to trying to get the optimum performance, versus keeping within strict cost controls. The ideal independent rear end had been found to be with trailing radius arms with coil springs and a live rear axle laterally located by a Watts linkage. However, the Watts linkage was discounted due to cost and was replaced by a Panhard rod.

A number of problems occurred during testing of the first prototype – now given the Longbridge number ADO23 – that could not adequately be rectified within the allowed budget. The simplest and cheapest way to fix the problem was to revert to leaf springs, like the MGA.

To give a softer ride, thus making the MGB feel more civilized on the road, the rear springs were made a little bit longer and used only three leafs instead of four. To ensure the car didn’t lose any of the MGA’s exceptional handling, though, Roy Brocklehurst inclined the springs slightly, inducing very slight understeer.

These changes meant making the car one inch longer and redesigning the boot floor to accommodate the leaf springs and still allow the spare wheel to lie flat. This in turn meant slight but essential changes to all the exterior lines of the car, which necessitated a second prototype – which was ready by mid-1961.

This car also included aluminium bonnet, boot and doors to reduce weight, but again costs meant these could not be included in the final production car – with the exception of the alloy bonnet, that was discontinued in 1970.

So, the production MGB was 50lb (23kg) heavier than the MGA – the MGA had alloy opening panels – which in turn would have meant slightly less performance. Just before the ‘B’ was finalized for production there was another specification change in the engine. The ADO17 project at Longbridge was supposed to have used the 2lt V4 of Duncan Stuart, but when that programme was cancelled, it was decided to fit the B-series engine instead….

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