The MG Story: The MGA

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The MG Story: The MGA


MGA
MGA

The MGA



Central figures clustered in the pit area at Silverstone's Woodcote corner were John Thornley and Sid Enever of MG, consulting with BMC Competition Manager, Marcus Chambers, with new recruits to a great racing team.

All heads looked left as an insistent purr sounded and a streamlined green two-seater hurtled through the bend, flat out in third gear with all wheels adrift. After a snap shift into top, driver Ken Wharton signalled "thumbs up" to the onlookers whilst the car machine belted on around the track.

The MG EX 182



This was EX 182, one of a team of three MG prototypes which were to take 12th and 17th places overall in the '55 Le Mans race a month after the Silverstone trials. If an observer at Le Mans, concentrating on the fast, reliable passage of these cars, could have turned back time to four years earlier, he would have been amazed at the strikingly similar green machine that was doing just as competent a job.

After taking 18th place at Le Mans in 1950 with a cycle-fendered TC special, lensman George Phillips persuaded MG to build him a special-bodied Mark II TD for the '51 event. Enever took this exercise seriously and produced a very nicely streamlined shell which allowed less than 70 horses to propel the car at better than 110. The overall experiment was successful and the car was stored for further research including construction of an intermediate prototype called EX 175, based on this TD's lines.

The next development step toward an aerodynamic MG was clearly a proper frame design; so work went ahead on a suitable layout and the construction of prototypes. An immediate incentive was MG's great interest and tradition in record-breaking, which, unlike racing, had never been snuffed out by Nuffield’s. It was then time to retire the venerable K3-based EX 135 in which Goldie Gardner had bowled over every class record within reach; so a similarly shaped EX 179 was built up, using the new chassis design, with appropriately punched lightening holes, sprung on TF wish in front and semi-elliptics at the back.

Using the XPEG 1500cc block, shortly before it was standardized for the TF, Ken Miles and George Eyston carded an armload of medium-distance records in August, 1954, with a peak speed of 247 kph. The EX 179 returned just two years later to hit 273 with a twin-cam B-Type engine, and was out once more in '57, setting Class G figures with a Morris Minor A-Type mill.

During the 1954-1955 winter all data was assembled, assessed, and applied to the finalisation for a new sports car design which was first authorised in June of 1954. The appeal of side and front styling that was similar to the ZA Magnette though the top was shaved off was checked and rejected. The Phillips-MG contours were given more professional treatments around the cockpit and tail. Then they were given the final touches in BMC's full-size wind tunnel. The result was the familiar shape of the EX 182.

These 1955 Le Mans cars were genuine prototypes, in that the production specs of the new car were to be called the MGA but were by no means settled as yet. The team machines had aluminium bodies together with a wild symmetrically ported head design by Westlake that produced 82 horsepower from the BMC B-Type engines that were used. So the MGA was made up from: a chassis from EX 179; front suspension from the TF; brakes, engine, and drive line from the Magnette; and body from a '51 TD special.

MGA Release



The changeover was duly made and MG's new model announced in late September, 1955. At the time such a revolutionary move by a factory steeped in tradition was bound to cause mixed reactions, with some of the concerns being due to the aerodynamic shape. The styling was quirky, with its dented grille and the tacked on taillights, but the overall impression was of unity and quality. Sales figures however, told the story, and response from buyers was positive and affirmative at the attractive original $2,700 base price. In all its versions the MGA became a best-seller with 103,000 produced.

"MGA" is an appropriate name. The letter "A" had the accurate sense of a new beginning and also infers what the car could have been named: "Austin-M G." Handed down directly from the Y-Type MG were basic steering gear and front suspension components, united by a TD-like front cross member. A completely conventional leaf system with lever-type Armstrong shocks carried the three- quarter floating hypoid rear axle, selected from BMC stocks.

The MGA Chassis



Completely new, the chassis frame was designed to unite the above assemblies in a full-width sports machine. It all started with two box-section side members whose section increased where stresses were found to be greatest. These members curve up over the rear axle and swept inward at the front to leave plenty of room for front wheel steering lock, but at the cowl and doors they were curved out as far as possible for to give maximum body support and to allow seats and floorboards to nestle in and not on the frame.

The MGA Frame



A distinctive frame feature was a heavy, rectangular, box-section arch at the firewall line, braced into the side members by boxed struts to the front and rear. Stresses taken by the front cross member were fed back along the front half of the chassis, which could take it with strength to spare. There were two cross-members under the gearbox and three-two tubular-spaced from the seats to the back bumper. Total frame weight was 82 kgs. Way over designed like all MG's, this frame was extremely stiff and stood proud from the body, which had no job besides fending off the elements. This approach made repairs easier, as contrasted with integral construction, with the MG being realistic in having four fenders which could be unbolted from the main pressings for replacement.

The MGA's Interior



Behind the driver's seat you could find the pull-loop which undid the boot. Opening it gave a good view of the covered spare tyre and tool kit but not much else. You could put a small suitcase in there, but during any rain it would get wetter in that boot than on the optional luggage rack. It was unfortunate that the MGA didn't learn a lesson in storage from by its contemporary, the TR Triumph. Carpeted and trimmed, the A's interior was very functional. An upright driving position was provided by the individual seats, which were moderately padded and adjustable. Lightweight doors had roomy side pockets and could be opened only by a pull-cord and with sturdy side curtains in place, the spring-loaded flaps had to be lifted to open the door which slowed down a would-be thief.

In spite of a casual dispersion of minor switches the MGA dash was a "genuine sports car," with a big tacho and speedo right in line of the drivers vision. A horn button on the dash was in the MG tradition, whilst the distinctive steering wheel spoke pattern came directly from an expedient on EX 179. The adjustable column became optional. At the centre of the dash were controls for the cowl-mounted heater and demister, which did a thorough job; however an additional cool air duct would have been welcomed. Suspended brake and clutch pedals, with the wider frame, gave lots more spare room for drivers feet. To allow for both right and left-hand drives, the cable-shaft lever throttle linkage takes a long way around to the twin SU carburettors.

The MGA's Engine



This was only the first of a long line of MG's to be powered by the basic B-Type BMG engine, which did itself proud in the A. A rating of 72 horsepower (68 in the early models) from 231 cms was a good average for this league, especially from an engine of its type. It responded very well to chamber and port improvements. There was a good feeling of torque at medium revs, which in part made up for resistance to wind up past 4500 and a practical ceiling of 5500rpm. You could use some of the yellow slice on the tach but red was strictly a no no without special preparations.

Under the hood most parts were easy to get at, thanks to a long opening, while twin batteries are under the spare at the rear. Dual cylinders, for brakes and the hydraullic clutch, were handy on top of the firewall. Interchangeable with TF's and late TD's was the Borg and Beck clutch, a good unit which needed conversion for racing and hard road use. The clutch housing was integrated with the case of the four-speed B-Type gearbox, which had a side opening to accommodate the column-shifting BMC machines. A long rear extension for the tail shaft carried an additional housing and linkage to a stubby gear lever.

The MGA's Brakes



Brake drums are 25cm in diameter and 4.4cms wide at all four wheels, with Lockheed mechanism featuring two leading shoes in each front drum. This was just the way the Le Mans cars were fitted. The handbrake was now tucked neatly away between the passenger seat and the high, wide driveshaft tunnel, where it was still easy to reach. Without brutal, all-out testing of prototypes the above characteristics might have added up to "just another sports car," but pains were taken to preserve the MG virtues of safety, ruggedness, and rapid response. Before their debut, hand-built MGA's were thrashed around England's community test track at Lindley, held flat out at Montlhery, and twisted through the bends of the Nurburgring.

The MGA's Steering



The payoff was quick and satisfying. This latest MG was a pleasure on the road. Rack and pinion steering and equal front/rear weight balance gave instant response to the wheel under, neutral, or oversteer depending entirely on tyre pressure and the amount of fuel being carried. Usually it was neutral, but with a tail end that will always be the first to go in emergencies. This was a leisurely process which left plenty of time for corrections and didn't vary unexpectedly when on different surfaces. If a certain sharpness of feel is sacrificed in the MGA, it was for the worthy purpose of providing this margin of time and distance for the less experienced sports car handler to make up his mind.

The engine was a big change from the previous. It was basically a BMC B-type unit souped slightly for more performance. Purists may said it wasn't really an MG, but it packed more wallop than even the 1500 XPEG. The A's wheelbase was identical to that of the T-Types and remained long for the compact dimensions of the car. Combined with good damping, this suppressed pitching over bumps, but the overall ride was still very MG-like. Suspension stiffness seemed greater at first than it actually was, held the A close to an even keel on corners and let you know what was going on in the tyres. With the good seats and enclosed cockpit, the ride was more reassuring than jolting.

The MGA's Acceleration



Acceleration wasn’t breathtaking, but most drivers found at the instant jump in first gear put them well ahead of slower traffic, while the 112 kph on tap in third gear could handle nearly any passing or climbing situation. A minor practical fault of the B-Type engine, shared with the TF-1500, was its tendency to keep running when the key was turned off. This was far more annoying than it damaging, but it could be alleviated by cleaning up the rough chamber surfaces.

The MG range was greatly broadened for 1957 by the addition of a coupe model which has already won many friends in this country. In spite of having a steel top, wind-up windows, and full interior trim, the "tin-lid" version weighed only 14.5 kgs more than the roadster, and it naturally had slightly better aerodynamics. The coupe traded a little more mechanical noise and poorer ventilation for much less wind noise and more luxurious fittings. Other than that there was nothing to choose between them except price.

The MGA Twin Cam



Even before the MGA was introduced the employees at Morris Garages were working on new twin-camshaft cylinder head designs. Two types were designed and built in 1953, as part of a program to overload the B-Type BMC engine to improve its bottom-end bearings. Experimental twin-cam engines were used in the Tourist Trophy Race in September, 1955, and in successful record-breaking events in 1956 and 1957. In its final supercharged version the engine developed 290bhp at 7300rpm, which was a pretty good test for the bearings.

In July, 1958, MG unveiled the production version of the Twin Cam as an addition to the line at a total list of $4,000. To suit the competition classes that prevailed the bore was made larger. At the top of the new bores and domed pistons was the aluminium cylinder head, with valves at an 80° inclined angle, and working through shimmed cups by chain-driven camshafts. Two big H6 S.U. carburettors were fitted and the output was 107 bhp at 6500 rpm.

Twin-Cam Performance



The Twin Cam's all-round performance wasn’t exceeded by any other production MG. The latest MGC just matched its acceleration and 200kph top speed. The added boost could be felt instantly. At 4000rpm, where the pushrod engine was starting to taper off, the Twin Cam was just starting to use its new­found power. Third gear in the optional close-ratio box is good for anything from 120 to 130kph.

handling was up to usual MG standards, with stiffer front coils and a heavier anti-roll bar countering added weight over the front wheels. Braking was in a new league, and boasted Dunlop discs inside all four wheels, the latter being special discs with pin-drive knock-off hubs. In street service the Twin Cam was a tricky animal, requiring exacting maintenance, but was regarded as extremely good indeed. It was also the rarest modern MG, only 2,000 being produced. Some Twin Cam chassis were also fitted with 1622cc pushrod engines and sold as a "Deluxe" or "Competition" model, at $4,000 in 1960.

MGA 1600



Running changes in the original MGA 1500 series (of which 58,750 were built) included heavier clutch pressure plate springs and the replacement of the 15GB engine by the type 15GD, which had a modified drive line. Much more important was the installation, from July, 1959, of the 16GA engine: the MGA 1600. It used the enlarged bore of the Twin Cam, bringing peak power to 78bhp at 5500rpm.

The additional punch made the 1600 the first 160+ kph post-war pushrod MG and greatly enhanced its cruising ability on long trips. Stopping power was added with 28cm Lock­heed disc brakes at the front only. Their major difference in "feel" was one of slightly increased pedal pressure, especially on a wet day. It was just a matter of pushing a shade harder, though, for consistent fade-free stopping. Other consequential improvements in the 1600 include a boot lid that could finally keep the water out, a front top bow that did likewise, and genuine sliding side curtains. Through April, 1961, MG built 31,086 of the 1600's.

MGA 1600 Mark II



Fittingly, the last of the MGA's was the best. Mark II meant more displacement and a higher axle ratio, to 4.1 from 4.3, which added up to a long-legged feel that was refreshingly advanced. The engine was thoroughly redesigned around a new 7.62cm bore which brought displacement to 1622cc, 250 cubic cm’s. Output was an even 90bhp at 5500rpm and torque was up another 1.55 Nm over the 1600, to 131 Nm at 4000rpm. Larger valves and carburettors, and a flywheel lighter by 3.6 kg’s, gave the Mark II the same lively, response feel that the equivalent version of the TD had eleven years earlier.

Reliability improved with the addition of valve steels, larger wrist pins, wider-section rods, thicker main-bearing supports and improved head gaskets for the higher B.9-to-one compression ratio. The Mark II's acceleration was better than the 1600's, in spite of the higher gearing, but it had the characteristics of a distance runner rather than a sprinter. Whilst quick off the mark, it was at its top end that it really came alive.

Other Improvements



From the outside the Mark II was easy to distinguish due to its recessed radiator grille and much neater tail lights. Leather covering for the cowl and the instrument panel added a look of luxury and reduced windshield reflections. As usual, the instrumentation was complete. Some owners liked to exchange the places of the fuel gauge (normally nearer the driver) and the water / oil combined gauge, while others insert an aluminium plate in the speaker grille opening to install an ammeter. The direction signal switch had a pneumatic delay, whose flashing cycle may be adjusted by means of a screw on the back. A pre-wired fog light circuit was built in. One note on the very useful re-settable trip odometer was not to try to zero or advance it while the car was moving as it would have been broken.

With aluminium doors, hood and boot lid, parts of the MGA body were subject to easy carpark damage. Bumper guards were a useful accessory as was a luggage rack which supplemented the small boot. A popular interior accessory was a scuff plate for the gearbox tunnel, beside the accelerator, which acknowledged the inevitable wear of the bare carpeting. Rubber mats to protect the floor were also a good investment. One of the best features of all typess of MGA's was their light and precise rack-and-pinion steering. Any play in the steering of a used MGA was likely to be in the ball joints or king pins. Engine oil pressure was about 75 psi cold at normal speeds and at least 30 psi when the oil became hot. The shocks needed attention and sometimes replacement if the MGA's excellent stock handling was to be retained.

Racing Record



Such was the pace of sports car development that the MGA it was better known as a fine road car than as a racer. The Twin Cam was built to race which it did extremely convincingly at Le Mans in 1960. Ted Lund over bored his Twin Cam engine to 1762cc and fitted a special fastback designed by Abingdon, which weighed the car in at a light 810 kgs. With Colin Escott he had a trouble-free 24-hour run, winning the class and finishing 12th overall. Le Mans is a blend of racing and touring, showing up the best in a fine all-round car like the MGA.

Also see: MG Heritage | MG Performance Chart
MGA
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