The MGB GT V8
The Background to the MGB
When the MGA had been announced in 1955, it had set new standards for MG in terms of performance and styling, but by the beginning of the 1960's it had become slightly out-dated. Sports car design had moved up a gear, particularly in terms of comfort and the prospective sports car buyer was demanding more sophistication than the MGA was able to deliver. For MG's sake, the replacement needed to offer better performance and a greater degree of comfort. History has now shown that the new car did have these features, for it was the venerable MGB, a car which was to sell over five times the numbers of MGA.
Like the Austin-Healey Sprite and later the MG Midget, the MGB was to be of unitary construction which brought
a number of advantages. The design of the body was such that the individual panels when welded together, produced
box-like structures of immense strength.
The engine and transmission came directly from the MGA, but the b-series engine had been increased in capacity to 1789cc, which resulted in 94bhp, and a diaphragm clutch was used between the engine and transmission. As standard, the car was supplied with bolt-on steel disc wheels, similar to those of the MGA but of a slightly smaller diameter.
The MGB was extremely well received by the press who were fulsome in their praise of the new car, which was capable of exceeding 100mph without any fuss. Performance handling and economy were all of a high standard for the time, which resulted in a thoroughly reliable sports car that was a joy to drive. It found a ready market, particularly in the USA.
When the MGB was introduced in 1962, it was a two-seat open roadster with squared-off styling which was in the Midget mould, and was to endure. It had a pancake-style rear hinged bonnet, full width grille, scalloped recesses for the headlamps in the tops of the front wings, a separate boot with a hinged lid, and canted rear lights in the ends of the rear wings. The windscreen was a curved item, there was a removable soft-top, and the doors had wind-up windows with hinged quarterlights. Aftermarket gas charged props have proved a popular upgrade for bonnet and boot hinges.
In the cockpit, driver and passenger had separate seats, and full instrumentation was provided, and a tonneau cover
to cover the space behind the seats when the hood was down.
Fortunately for owners now, there is the wind blocker to stop that wind
buffeting when the MGB top is down.
The MGB was a bit shorter than the MGA, but the design was such that MG had managed to make the cockpit roomier which allowed larger, more comfortable seats to be added.
A year later in 1963, among the options offered for the MGB were an overdrive for the transmission, centre-lock wire wheels, and a folding soft-top that could be stowed behind the seats. And in 1964 a much stronger bottom-end for the engine, derived from the BMC 1800, was fitted.
In the tradition of the earlier MG sports cars, the MGA had been built with a separate chassis to provide support and strength to the car, and to carry all the mechanical components and the body. By the end of the 1950's however, methods of car construction had moved on , and the days of the separate chassis were almost over. Unitary construction was now the name of the game, whereby a cleverly designed bodyshell constructed from a number of metal panels with a reinforced floorpan, provided mountings for all the mechanical components and absorbed all the loads from the suspension etc. The advantage of this type of construction was that it produced a much lighter car, which has obvious performance benefits for a sports car.
Hence, the MGB was to be built of unitary construction. At the front, the inner wing panels, front panel, and engine
compartment bulkhead formed one box; the scuttle, bulkhead, and front floor formed another; while the rear inner
wings, boot floor, and rear panels formed another. Box section strengthening pieces were added to the floor to stiffen
it and provide mountings for the rear suspension, while additional box sections ran along the bottoms of the front inner
wings for the engine and suspension mountings.
The front suspension and steering were much like the MGA, although there were minor differences. At the rear were the familiar semi-elliptic springs controlled by lever-arm dampers. The engine and transmission were also MGA sourced, again with some minor changes.
In 1965 came a coupe version of the MGB - the MGB GT, which had an attractive and functional closed version of the standard body. In appearance, the front end, front and rear wings, and doors were essentially the same as the roadster, but the windscreen was slightly higher to allow for a higher roof line on the car. The roof ran back in a gentle curve over the doors and rear side windows before sloping down into the rear panel. In the place of the roadsters small boot lid was a much larger hinged tailgate that provided access to the loadspace inside, making it one of the earliest examples of the now popular hatchback car.
Inside, a small rear seat was provided but this was not much use except for carrying children. However, the seat could
be folded flat to provide a large load platform for luggage, making the GT a really useful two-seat touring car. Although
the coupe bodywork made the MGB much heavier, its shape actually helped the cars performance by the improvement in
aerodynamics the roof brought. This gave the GT a slightly higher top speed than the roadster, and also an improvement
in handling since the roof put more weight over rear end, but this weight had a detrimental effect on the cars
The MGB GT was not only a good looking car, but it offered saloon car comfort levels with a sports cars performance. As a result, the GT became very popular with those who wanted something more civilised than a roadster.
This guide to wiring to the fuse box on a 1972 MGB GT has been compiled by Brian Wall from the AKD 3259 (15th Edition) workshop Manual
Both models continued until 1967, when the MGB MkII was introduced, still in open and GT forms. The most significant difference was that the new model had a new transmission with synchromesh on all four gears, and a better set of ratios. This necessitated widening of the transmission tunnel, which also allowed MG to offer the option of automatic transmission, which may seem strange for a sports car but it was felt that new customers attracted by the GT would take to the idea.
Also in 1967 a new MG model was introduced. This car was based on the MGB, and was intended as a replacement for the Austin-Healey 3000 which had had its day. This was the MGC.
By the late 1960's, the MGB was beginning to be affected by exhaust emission and safety legislation which required frequent
modifications to the cars specification. This was particularly the case with those models destined for export, especially
for the USA.
Detail modifications continued until 1970 when the most obvious change was to a matt black recessed grille which, unlike the original grille, had no obvious link to the MG grille of old. Other changes included modified rear lights, Rostyle sculpted steel wheels, and revised interior fittings. There was also a change to SU HIF carburettors in an effort to improve the exhaust emissions problem.
In 1973, another big engined MGB appeared on the scene, but unlike the MGC, this one was to be extremely well received to the extent that demand far outstripped supply. But in spite of this, this car was also to disappear after a relatively short production run - it was the MGB GT V8.
A former Mini racer turned car tuner named Ken Costello set the scene for what would follow when he uprated an MGB by ditching its heavy iron straight four 'B-Series' engine in favour of the ex-Buick alloy V8 engine which had been adopted by the Rover Car Company. It did not take the engineers at Abingdon long to get wind of Costello's exploits - and indeed no less a person than British Leyland boss Lord Stokes invited Costello to demonstrate his prototype. Within a very short space of time, MG was given the go-ahead to build its own prototype - work on which began in August 1971 - but between then and the launch of the factory MGB GT V8 two years later, Costello was able to do healthy business. Naturally Costello stole a march on British Leyland since he had no corporate "red tape" to deal with - so while MG had to deal with the problems of type approval and other modifications, Costello was able to shoehorn the engine into place on a custom-built basis. When MG launched its own MGB GT V8, the hitherto easy supply of parts essential to Costello's own conversion began to be stemmed, but undaunted, Costello found it cheaper to buy secondhand Buick engines from Belgium, which he brought back by the lorry-load and rebuilt using new Rover parts.
The car made use of the 3532cc aluminium Rover V8 engine as was being used in the Range Rover. Developed from an early Buick design, the engine was very light in weight - it actually weighed less than the original B-series MGB engine - and in standard tune offered a healthy 137bhp. It fitted snugly into the MGB's engine bay after only slight modification to the bulkhead, and with the development of a low-rise manifold allowed MG to use the standard MGB bonnet. Furthermore, the engine could, unlike in the MGC, be fitted without dispensing with the front suspension crossmember, so the coil-spring type suspension could be retained. The standard suspension was employed at the rear too, but the ride height was increased by an inch all round. The engine was mated to the MGC gearbox and rear-end transmission, although the ratios were slightly modified.
The combination of the Rover V8 engine and the MGB produced an excellent touring car with high performance, good economy,
and good handling. The press received it well and it found a ready market, although it was never exported to the USA for
some unknown reason.
In 1976, the car was killed off, supposedly because of the limited supply of engines, which were being built under licence and were required for Rover's new SD1 saloon. Another contributing factor to the cars demise was the fuel crisis which was experienced in 1975, which led people to buy smaller engined, more economical cars. Given the obvious success of the car, it seems strange that it was ended, and possibly there was more to it that just these factors. The MGB GT V8 was, after all, in much greater demand than Triumph's V8-engined Stag, which continued in production...
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Two years earlier, in 1974, both roadster and GT (including the V8) had received the black "5mph" bumpers and an increase in ride height, in much the same way as the Midget had done. The front bumper was shaped to merge into the grille which at least had a token resemblance to the earlier traditional shape. As with the Midget, the weight of the bumpers and increased ride height did nothing to the cars handling, increasing roll and oversteer. An attempt was made to rectify this problem in 1976, when stabilisers were fitted to the front and rear suspension, which was quite successful and considerably improved the cars handling.
The MGB continued in this form, with further detail changes to the specification, until production finally came to an end in 1980. By then the car was definitely past its best, but there was no replacement to be had. Development work had been stopped at Abingdon, for British Leyland preferred to concentrate on their Triumph products. It was claimed that BL were losing money on every MGB built, but this was hard to believe since there were few major changes to the cars specification over the years, so development costs must have been recouped long before the end.
However, the end it was, not just for the MGB, but for MG and Abingdon as a separate entity within the British Leyland
group. The plant was closed, but the furore this caused among MG enthusiasts around the world caused the parent company
to realise that the MG name was a valuable commodity.
While it was thought that the MG name as a sports car manufacturer was dead, the name lived on being carried by a number of BLs sporting saloons, and is now being re-born by the now Rover Group in the guise of new sports cars - the MG RV8 and the new MG MGF.