MG Z- Type Magnettes
Jigs and presses were still kept busy at Abingdon, stamping out MG ZA-Type Magnette sedans. This model was introduced about the same time as the TF-1500 and was more readily available. It was important because it symbolised the changes in MG policy that took place under BMC supervision. The most obvious repercussion of the Austin-Nuffield merger in '52 was a period of engine swapping and simplifying. The goal was three basic engines: the A, B, and C- Type, for small, medium, and large cars, respectively. Whilst undeniably efficient, the thirteen-year-old XPAG engine was for its time outdated and not could not readily adapt to high-pressure production methods.
So development toward a suitable B-Type unit was applied to the four-barrel that then powered the Austin A-40. Destined for the then highest unit production ever achieved in the UK, the resulting 1489cc engine first appeared in the Series II Morris Oxford in May of 1954 and subsequently spread to the A-50 Austin, the MG and Wolseley lines, the Metropolitan, and finally to the new 1 1/2- litre Riley. One product from this inter breeding was the new Magnette, which inherited an integral four-door body from the Wolseley Four Forty-Four, which in turn had been using the XPAG engine. It also inherited some voluble resentment at the revival of the Magnette name for a touring car.
General layout of the B-Type engine followed A-40 lines very closely, with the bottom end well beefed-up to take the expected power increases. To ensure a solid union between block and clutch housing, the crankcase sides were extended down past the crank centreline to a joint with the pressed oil pan. 7.62 cm mains, with slightly recessed two-bolt caps, carried a forged steel crankshaft with end thrust taken at the centre main. Bottom end bearings were steel-backed white metal or indium-plated lead-bronze, depending on the year and make of the car. The latter was the heavier-duty type.
Admirers of MG's didn't escape the split and bolted rod wrist pin end retained to keep noise down in these mainly touring engines, and they acquired a two-bolt big end split diagonally to allow withdrawal of the rods from the top and offset lengthwise to shorten the crankshaft. Material was top shelf, like most BMC engine parts, the H-section rods being forged steel of the same quality used in the crank. Pistons were of aluminium alloy with split full skirts and four rings, only one being an oil scraper. Forged and case-hardened steel, the three-bearing camshaft sat in about the same place the XPAG's did, at the upper left of the crank. Its double roller chain drive was held tight by a rubber-faced shoe under spring pressure, supplemented by a self-adjusting ratchet.
A single skew gear between the cams of number three and four cylinders drove the vertically placed oil pump and the
Lucas distributor, which was on the right with its shaft angling through the crankcase. Piston-type
tappets are of cast iron with chilled faces, and actuate a thoroughly conventional pushrod and adjustable rocker valve gear. Combustion chamber and port design for the new BMC engine series was handled by a well-known consultant named Harry Weslake, with his co-workers spending much time pumping air through wooden port models, checking, chopping, and filling with files and plasticine. They came up with a unique heart-shaped chamber which promoted turbulence and coolness of the incoming mixture. Placed at the point of the heart shape, plugs were on the right-hand side of the head.
There was an excellent reason for running the ports out the pushrod side of the head, but who knew what it was. All ports except the two end
exhaust outlets were co-joined, and for touring power outputs they were adequate, and had been highly refined by Westlake’s crew. For some unknown reason, were the canted valves and the quench chamber characteristics of the XP series engines were avoided. Two 3 cm SU's fed the B-Type engine in the ZA Magnette, which gave it some zest that was neatly handled by the four-speed Austin-derived gearbox of the same series. With a slightly longer floor lever, giving better leverage, the fast, clean shifting of this box compared well with that of the TF with always a high standard and had the added attraction of a reverse slot to the left and back.
Handsomely finished and fully-equipped, the Magnette sedan was an excellent touring machine.
Its foam-cushioned individual front seats invited you to settle back and drive; while
steering and
handling in the MG tradition made it an enjoyable experience. There was roll and rear end flexibility, which occasionally introduced some guesswork, but damping was good and recovery quick. In all 36,000 ZA and ZB Magnettes were built.
In the minds of the designers, as well as in the history of the MG Car Company, this had been a period of flux and experimentation. The TF and TF-1500 represented the ultimate development of the transitional semi-classic TD style; while the Magnette pointed towards the future. Both cars rated tops in their classes, being impressively strong in construction and responsive to all controls, the true hallmark of a sports car. Having carried these attributes through some thirty years of history, the workers at Abingdon were not about to stop.
The First New Model Since 1936
The MG Magnette was the first car to bear that name since 1936 and first MG saloon since the Y type was discontinued in 1951. It reached Australia just in time for the Sydney Motor Show. It was also the first MG to have a mono-construction body and chassis. Apart from the traditional (though curved) MG radiator, the body was like that of the Wolseley 4/44 - but in everything else, it was a vastly different car. The new 1.5-litre B.M.C. engine, designed specially for the Magnette, had overhead valves, a capacity of 1489 c.c., and developed 60 b.h.p. at 4600 r.p.m., whereas the Wolseley's 1250 c.c. engine gave 46 b.h.p.
The Magnette had a different dash arrangement, with all instruments grouped in front of the driver, a central remote-control gear change (instead of the steering-wheel level), and twin S.U. carburettors. The Magnette's body was also lower than that of the Wolseley. Another difference was in the clutch, which was hydraulically actuated on the MG. Other highlights of the new Magnette included the following: a turret-type four-seater body of great strength and completely rust-proof; a very good power/weight ratio; an extremely large luggage boot; leather upholstery with deep, well-sprung cushions and a folding centre arm-rest at the rear; attractive lines; and very good finish.
Engine and Transmission
The MG Magnette’s engine had a bore and stroke of 73.025 mm. and 89 mm. respectively. The overhead valves were operated by push-rods from a three-bearing camshaft driven by a Duplex roller chain. The gear-type oil pump in the crank-case was driven by helical gears and a vertical shaft from the camshaft. The crankshaft had three bearings and was balanced. Compression ratio was 7.15 to 1. Ignition was by 12-volt battery and coil. Automatic advance and retard was fitted, with vacuum control and vernier adjustment. Suppressor equipment was included.
The twin S.U. semi-downdraft automatic carburettors were fed from a 9.5-gallon rear tank by an S.U. electric fuel pump (rear-mounted). A large oil-bath air cleaner was fitted. A Borg and Beck single-plate dry clutch was employed; and the four-speed gearbox had synchromesh engagement for second, third, and top gears. Gear ratios were 17.745, 10.793, 6.698, and 4.875 to 1; reverse 23.205 to 1. Clutch and brake pedals were of the popular hanging type. The back axle was of the semi-floating type with hypoid final reduction gears and was controlled by a torque arm.
Brakes, Wheels, Suspension
Fully compensated Lockheed hydraulic brakes were employed, with two leading shoes in front. The simple shoe adjustment simultaneously adjusted the handbrake, which had a central lever with press-button ratchet control. The wheels were the ventilated disc type, with Dunlop 5.50in. x 15in. tyres. Rack-and-pinion steering was employed. Turning circle was 37ft. 6in. The independent front suspension was by wishbone links, with coil springs and telescopic dampers. Rear suspension was looked after by rubber-mounted, semi-elliptic springs damped by telescopic hydraulic shock absorbers with anti-sway mounting. The dampers slope outwards towards their lower ends, thus aiding stability.
Body and Fittings
Dimensions of the Magnette were: wheelbase, 102in.; height, 58in.; width, 63in.; track, 51 in.; length, )69in.; ground clearance, 6in. Weight of unladen car is 22 cwt. The mono-construction body incorporated the body shell, floor, bulkhead, and frame members. Armrests on the rear doors acted as door-pulls. Self-locking check straps held the doors in the open position when desired. Polished wood was used for the facia panel and door capping. The windscreen was curved and in one piece, and there was an extremely large curved rear window. The spare wheel was housed vertically on the left inside the large boot, the lid of which is counterbalanced by torsion-bar hinges for easy lifting and will stay put in any position.
Specification included: a petrol-tank filler concealed by a flush-fitting panel and fitted with an anti-thief lock operated from inside the boot; two pull-out ashtrays on the facia, and one on the back of each of the two front seats; bucket-type front seats with individual adjustment; an inbuilt forced ventilation system with controllable fresh-air intake and inbuilt demisting ducts; a special jack and jacking points; windscreen-washing equipment; and provision for wireless, with a central speaker grille in the facia. The radiator grille was integrated with the bonnet and lifts with it, giving excellent engine accessibility. Everything seemed to have been studied for the comfort and convenience of those who travelled in the car: there was an engine temperature indicator, an electric clock above the rear mirror on the roof rail, and a parcel tray behind the rear seat.
Also see: MG History |
MG
Performance Chart |
The MG Magnette Car Review 
