M.G.—The Breed Improved
NEW MODEL A PROFITS BY RACING EXPERIENCE[Top photo caption:]
Strong bumpers follow the contours of the new M.G.’s front and rear wings and radiator. The curved windscreen can be replaced by a shallow screen for competitions.
WHEN the M.G. Car Company announced its participation in the Le Mans 24-hour race, after a lapse of 20 years, the three cars entered were acknowledged to be prototypes for a possible new production car. Two cars out of three finished (one crashed), and came 12th and 17th in the classification on distance covered; the totals during the 24 hours were 2,084 and 1,961 miles respectively. Nobody will deny that this performance of the model, after the company’s long absence from racing, was impressive. –
From these Le Mans cars, known as the type EX 182 (a full description of which was given in The Autocar of June 3), has been developed the production series M.G. A. It is apparent that the experiment of Le Mans was considered successful, as the car shows no basic changes from those cars which took part in the race, but detail modifications have been made for normal road use.
Equipped with the 4.3 to 1 axle ratio, the car is capable of nearly 100 m.p.h. in towing trim with hood and sidescreens erected. At the moderate price of £844 Os l0d, including purchase tax, it becomes a serious challenger in the 1½ litre sports car class. Its appearance, with its wind-cheating body, is a complete departure from the shape of previous models from the Abingdon factory.
The four-cylinder engine is basically the B.M.C. H-Series unit, as used in the Magnette saloon. It is equipped with two semi-downdraught l ½ in S.U. carburettors and the compression ratio has been raised to 8.3 to 1, with a peak output of 68 b.h.p. at 5,500 r.p.m. Maximum torque is produced at 3,500 r.p.m., at which speed the b.m.e.p. is 128.8 lb per square inch.
Siamesed inlet ports are used and the short induction manifold for the two carburettors is bolted direct to the face where these merge into a common bore; a balance pipe connects these two short induction stubs. This is different from the Le Mans cars, wherein the induction ports were connected through to the opposite side of the head and an external balance pipe was used on the other side from the manifold. Presumably this extra complication did not give a worthwhile improvement in power output on the production version.
The overhead-valve engine, with a bore of 73.025 mm and stroke of 89 mm (1,489 cc.), has a sturdy three-bearing crankshaft which runs in white metal thin wall bearings, this type also being used for the big-ends. A heart-shaped combustion chamber is used in conjunction with in-line vertical valves operated by rockers and push rods from the side-mounted camshaft, This is driven from the front end of the crankshaft by a duplex roller chain. Lubricant is supplied by an eccentric rotor pump driven by the camshaft and this feeds the oil through a full-flow filter to the main oil gallery, from which the drillings to the main bearings are taken.
Each carburettor is fitted with a wetted game-type circular air filter and cool air is ducted to these from a large-bore flexible pipe with its entry placed to the left-hand side of the front grille. A high-pressure S.U. electric fuel pump is mounted on a chassis cross-member behind the driving seat and draws fuel from the 10-gallon tank. The tank, which has an external filler, is placed below the floor of the luggage locker between the chassis frame members.
From the engine the drive is taken through an 8 in Borg and Beck single dry plate clutch with six pressure springs and hydraulic withdrawal mechanism.
• Engine.—Capacity 1,489 c.c. (90.88 cc in). Number of cylinders: 4. Bore and stroke:
73.025 x 89 mm (2.875 c 3.Sin). Valve gear:
overhead, push rods and rockers. Compression ratio: 8.3 to 1. B.H.P.: 68 at 5,500 r.p.m.
Torque: 77.4 lb ft at 3,500 r.p.m. Max. b.m.e.p.: 128.8 lb per sq in at 3,500 r.p.m. Speed on top gear at 1,000 r.p.m. with 4.3 rear axle ratio, 17.0 mph.
Clutch.—Borg and Beck, 8 in single dry plate.
Transmission.—Overall ratios, top 4.3, third 5.908, second 9.520, first 15.652, reverse 20.463 to 1. Synchromesh on second, third and top.
Bear Axle.—Three-quarter floating with hypoid drive. Standard -ratio 4.3 to 1 (4.55 to 1 ratio available if required).
Brakes.—Lockheed hydraulic. Front, two-leading shoe; rear, leading and trailing. Drum dimensions: F, l0 in dia., l ¾ in wide. R, l0 in dia., 1 ¾ ins wide.
Tyre Size.—5.60-l5in on disc wheels. Pressures, front, 17 lb pa sq in; rear, 20 lb per sq in.
Steering Gear.—Cam Gear,. Rack and pinion. Turning circle L and R, 28ft.
Electrical Systems.—12-volt by two 6-volt batteries. 5 1—ampere—hour capacity.
Tank Capacity.—10 Imperial gallons,. Oil sump, 6 ½ pints. Cooling system, 10 pints.
Dimensions.—Wheelbase: 7ft l0in. Track: F, 3ft ll ½ in R 4ft O ¾ in. Length (overall):
l3ft. Height: 4ft 2in with hood raised. Width: 4ft l0in. Ground clearance: 6in. Frontal area (hood raised): 13.77 sq ft (approx). Weight, depending upon extras fitted, 1,900 to 2,000 lb.
Price (Basic).—With two-seater body, £595. U.K. purchase tax: £249 0s l0d. Total price in U.K.: £844 0s l0d.
Optional Extras.—Provision has been made for fitting H.M.V. car radio. Wire wheels are available as an extra if specified with order. Other optional extras are heater, white wall tyres, 4.55 to I axle gears, twin horns external luggage carrier, fog lamp, overall tonneau cover, radiator blind, chromium-plated wheel rim embellishers and telescopic steering column.
M.G.—The Breed Improved
[Top drawing caption:]
The balance pipe on the M.G. A is on the carburettor side of the head. On the I.e Mans engine the ports went across the head to a balance pipe on the other side
A standard B.M.C. B-type gear box and combined clutch housing is mounted on the cylinder block at the rear engine plate. It is a four-speed unit with synchromesh on second, third and top. The ratios are: top direct, third 1.373, second 2.21 and first 3.64 to 1. From the top of the gear box casing above the selector forks, a separate casting extends rearwards and contains the mechanism of the central remote control. A short vertical lever rises from this extension and is well placed in relation to the steering wheel. The travel of the change speed lever knob is short, a desirable feature for rapid changes. An oil filler cap, with dipstick, is placed on the left-hand side of the gear box casing and is reached through a hole in the tunnel which surrounds it.
The gear box casing is extended to reduce the length of the Hardy Spicer propeller-shaft which connects the drive to the three-quarter floating hypoid spiral bevel rear axle. The standard crown wheel and pinion give a ratio of 4.3 to- 1, but an alternative ratio of 4.55 to 1 is offered. An orthodox bevel gear differential with two pinions is used.
The front suspension is identical with that of the previous TD and TF models, and was also used on the Le Mans cars. It is conventional in layout, using coil springs in conjunction with unequal length wishbones. No anti-roll bar has been found necessary, and this is undoubtedly because of the low centre of gravity of the car and its mean track of 4ft, which is wide for its size.
The top wishbone consists of two forgings attached at their inner ends to the cross-shaft of the Armstrong piston-type spring dampers and bolted at their outer ends to the king-pin post. The lower wishbone is a steel pressing consisting of two identical arms bridged by a centre section which forms the seat for the helical coil spring. The upper end of the coil spring fits into a housing formed by an extension of the main front cross-member, to which is also bolted the conical rubber bump stop.
In common with other M.G. models, rack and pinion steering gear is used, mounted ahead of the suspension unit and connected to the steering arms by a short track rod at each side. A single universal joint is incorporated in the shaft between
the steering wheel and the rack and pinion. Like several cars nowadays, the M.G. has, strictly speaking, no steering column, the shaft rotating where a column remains stationary. It is customary to shroud the top end of such a shaft with an extension pressing from the facia.
Half-elliptic springs are used at the rear, mounted directly beneath the frame side members. They are shackled at their rear ends and controlled by vertical piston-type Armstrong dampers bolted to the inside of the frame members. Check straps control rebound and rubber bump stops are mounted on the underside of the frame where it sweeps up over the rear axle.
Disc wheels with ventilation holes and four-stud attachment are supplied as standard, but wire-spoked centre-lock wheels can be obtained as an optional extra. Dunlop 5.60—Thin tyres fitted on 4.00—Thin well-base rims are used with both types of wheel.
The AUTOCAR, 23 SEPTEMBER 1955
Lockheed hydraulic brakes with l0in-diameter drums and 1 ¾ in-wide shoes are fined. Two-leading shoe operation is used in the front drums and leading and trailing shoes at the rear. Actuation is by a pendant pedal mounted on the scuttle and connected to the master cylinder by a short operating rod. The master cylinder is a duplex unit with a similar pedal for clutch actuation. Mounted in this position, the two master cylinders are accessible for topping up with fluid. The fly-off type hand-brake lever is located between the seats dose to the propeller-shaft tunnel and is connected to the rear brakes by cable.
The chassis frame is based on two side members boxed throughout their length and spaced to the full width of the body, which gives a low seating position because the floor is flush with the underside. At the front end they sweep in to give the necessary wheel clearance for the good turning circle of 2Sft, which the designers have provided for easy manoeuvrability. The frame is given extra rigidity by extensive bracing at the scuttle structure over the clutch and gear box; stiffening of this section is further increased by a tubular cross-member placed under the transmission at the same point. Although it is rather heavy, the frame possesses very good torsional rigidity, which is reflected in the outstanding road-holding qualities of the car.
The body is panelled in steel and the doors in aluminium. Much research work has gone into the design of the body to reduce the wind resistance, and because of this it is a complete breakaway from the traditional lines which have been associated with this make for so many years. At the same time, the traditional M.G. character has somehow been retained, and the front grille is so styled that its classical origin is at once apparent.
Lucas double-dipping head lamps with pre-focused bulbs and blocked lenses have been blended into the contours of the front wings so that they rise above the falling bonnet line. Separate side lamps are placed immediately below the head lamps, lust above the swept-round bumpers, which also carry overriders.
Separate bucket-type seats are placed low down between the widely spaced chassis side members and the propeller-shaft tunnel, to the top of which is fixed a permanent armrest. Good access is achieved by the use of forward-hinged wide doors at each side. They are hung on concealed hinges with no exterior handles, the opening being controlled by pull cables in the spacious door pockets. The hood folds away out of sight behind the rear seat, which area is also used for side screen stowage. The seat back-rests are hinged forward to allow easy access to this compartment. An overall tonneau cover can be supplied at extra charge.
Luggage space is provided above the petrol tank and access is from the outside of the car. The hinged lid to this compartment is released from inside the body by a catch behind the passenger seat. The spare wheel is placed horizontally on the luggage compartment floor, and is canvas covered.
Twin six-volt batteries of 51 ampere— hour capacity are located beneath the locker floor, one on each side of the propeller-shaft.
A single-piece bonnet, hinged at its rear end and supported in the open position by a stay, gives access to the engine compartment.
The curved, one-piece, sloping windscreen is provided with grab handles at each corner which add considerably to the stiffness of this fitting and make it completely free from any vibration or other movement. The four sprung spokes of the steering wheel are arranged to give a clear view of the vital instruments in front of the driver. These consist of a 4in speedometer with dead-beat reading and incorporating a head lamp high beam warning lamp. To the left of the speedometer is a matching 4in revolution counter with ignition warning light. A combined oil pressure and water temperature gauge completes the range of essential instruments
M.G.—The Breed Improved
immediately in front of the driver and a rheostat-controlled panel light, map-reading light and fuel indicator gauge, make up, with the normal range of switches, the functional yet attractive facia panel.
There is a wide range of optional extras if required. Provision has been made for the fitting of H.M.V. car radio, and others include white wall tyres, twin horns, an external luggage carrier, fog lamp and tonneau cover. In the same category are a radiator blind, wire wheels, telescopic steering wheel and the axle ratio of 4.55 to 1.
This new car appears to be a worthy successor to the famous and well-loved T-types, incorporating many lessons learned in racing. At its price it is a desirable car for normal road use, yet is still suitable for competition in the 1,500 c.c. class. In view of the increasing popularity of sports car racing, there is available from the factory both the information and the necessary parts for those owners who wish to increase further the performance of the A model, in the same way as they could its predecessors.
TO confound the critics who say that racing teaches no useful lessons comes the brand-new M.G. sports two-seater. Designated the model A—thus starting afresh after the long line of M, J, Q and R racing cars, and TA, TD and TF Midgets that rolled out of the Abingdon works—the new car is a very close development of the M.G.s that did so well in the 24-hours race at Le Mans this year.
There are naturally some differences between the racing car and the production model, but the road holding, braking and steering are unaffected and in these respects the M.G. A recalls very intimately the Le Mans car, road impressions of which were published in The Autocar of July 29, 1955.
The immediate impression on sitting in the driving seat was that the car had been tailored to fit, of which more later. Starting the 1k-litre B.M.C. engine presented no problems. A radiator blind, as fitted to the test car, is available as optional extra equipment and is easily operated by a control below the right-hand corner of the facia. This blind facilitates the warming-up in which any right-thinking enthusiast will indulge, although even without its use operating temperature was reached very quickly.
On opening the cable-operated throttle there came the familiar M.G. exhaust note. At no time did this become objectionable to others, and there was no annoying boom to be heard with the hood up. The car will drift along through residential areas on a whiff of throttle and with no unwelcome attention attracted.
There is immediate response to sudden pressure on the accelerator and the getaway from rest is very good, 70 m.p.h. being reached in just over 21 seconds. On wet roads, which were experienced during the taking of the acceleration figures, wheelspin was very apparent, and black lines can be left on a dry surface if the start. is abrupt. At the end of the standing quarter mile the M.G. was travelling at very nearly 70 m.p.h., and this was, very creditable with the load carried. Performance figures were taken with hood and sidescreens erected, except for some runs to determine maximum speed, when a small racing-type screen Was fitted.
With this small screen and a tonneau cover over the passenger seat, the best speed reached was 96 m.p.h., as against 99 m.p.h. with the hood and sidescreens in position. At such high speeds the M.G. A is very stable and the driver is able to concentrate on the rev counter needle as it climbs to the orange 5,500 r.p.m. mark on the dial, and the road shooting past him and away under the nose of the car. On Continental roads it was possible to cruise for mile after mile with the speedometer needle between 90 and 100 m.p.h. The oil pressure and temperature gauge needles remained steady in spite of a considerable amount of high-speed driving.
The M.G. A is, in fact, one of those cars whose cruising speed is determined by road conditions, and this became very evident after driving fast over the French and Belgian roads. But there is no feeling at the end of a hard day that the driver has been doing most of the work. Long, winding hillside roads are a joy to traverse; the car rockets to the top in third gear, and this gear is also extremely useful for overtaking other traffic and for town use. Yet it is possible to accelerate smoothly from 12 m.p.h. using the 4.3 to 1 top gear, and the car can be very pleasant when used in a gentle fashion. The engine is no temperamental unit, liable to behave only when it thinks it will.
Fuel consumption benefits from the body shape; driving at 50 m.p.h., with short periods at 70, resulted in a figure of 30.8 m.p.g., which was achieved on a give-and-take main road in Great Britain where to maintain the predetermined average speed the available acceleration had to be used.
The road holding and steering are of a high order. Even with the tyre pressures set for fast driving, there was no feeling of discomfort or pattering when on pave and other poor surfaces. Fast cornering was a joy, the driver being able to position the car exactly where he wanted, and exit from a corner is also very satisfactory. On roads just wet
[Top photo caption}
Frontal structure, rack and pinion steering and independent suspension of the new M.G.
after a sudden rainfall, the tail of the car would swing out slightly, but correction brought an immediate response and there was no lack of control. Suspension and damping is such that the whole car feels in one piece and the front end does not hop about.
The rack and pinion steering, with one of the aesthetically better types of present-day steering wheel, has a good, easy action with very little lost motion. There are two and three quarter turns from lock to lock and the car proves to be guided by a slight motion of the hands rather than turning the wheel through a number of degrees.
Control is helped at all speeds by the excellent driving position previously mentioned. The seat is low down, below the level of the frame, and the driver’s legs stretch comfortably to the pedals. The steering wheel (nonadjustable column) is at a good angle and there is plenty of room for the driver’s elbows. The sight line of a tall driver is well below the top of the windscreen, and there is space for large feet in the neighbourhood of the pedals. The short remote control gear lever comes immediately to hand and the movements are precise and extremely satisfactory, the results being equally so! Occasional difficulty was encountered in engaging first gear from rest. The reverse stop spring on the ear tested was also rather stiff, but experience of a similar gear box has shown that this stiffness wears off. The clutch is hydraulically operated and has a nice feel. It is capable of enabling very quick gear changes to be made without slip.
Racing experience shows in the M.G. A braking, which is all that could be required for very fast road work. Two-leading shoes in the front brakes, with leading and trailing shoes working in the rear, give the driver all the retarding power he is likely to need in normal circumstances. No fade was experienced during the test, and only when the brake performance figures were being obtained did any unevenness set in. The fitting of centre-lock wire wheels, an optional extra, would assist in cooling the drums as well as improving the already attractive appearance of the car. The hand-brake lever lies horizontally by the side of the propeller-shaft tunnel and has a fly-off action. It is easily reached and does not get in the way of the driver’s leg.
Fast night driving is quite safe with the beam of the head lights, but the foot-operated dip-switch is placed rather high and is difficult to reach. It would be considerably better if it could be adjacent to the clutch pedal. There is a rheostat for the instrument lighting, and at one position of the switch the speedometer alone is illuminated. The only reflection in the windscreen comes from the tonneau cover studs immediately in front of the steering wheel. With the hood up and head lamp beams reaching away in front. the M.G. A is as comforting to drive at night as it is exhilarating by day.
Both seats have adequate adjustment and the back rest is at a comfortable angle. Some drivers would prefer more support for the thighs. The passenger has a grab handle and this also forms the windscreen frame support. As is to be expected, it is easier for two persons to erect the hood from its stowed position behind the seats, but the driver alone can manage it. The sidescreens, which have a spring-loaded flap, are simple to put into position and remove; they are each locked by one turnbuckle. Some wet came in between the windscreen and front edge of the sidescreens when travelling fast, and in extremely heavy rain water dripped on to the driver’s right leg from a point under the scuttle. There is a very reasonable amount of head room with the hood erect, and there was no instance of the driver’s head hitting the hoop sticks when going over a bump. At speeds between 70 and 80 m.p.h. the hood
For a sports car, luggage space is reasonable. Hood up, the new model loses nothing in smartness; the rear window is flexible
A new slant on the familiar M.G. front, successfully adapted
Seats tip forward if required. Instruments confront the driver but the horn is in the centre of the facia
THE AUTOCAR, 23 SEPTEMBER 1955
material vibrated on the frame but this noise was not experienced at lower speeds.
There, is no cubby-hole in the facia; the space occupied by the radio fitted on the test car is blanked by a plate with an M.G. motif when there is no radio. A large pocket in each door is sufficient for maps, torch and the usual odds and ends crews require for a few days away from home. The pockets remain dry in rain when sidescreens are not fitted. The door handle cord is slung across the inside top of the pocket and can be reached by inserting a hand underneath the flap of the sidescreen. There are fitted envelopes behind the seats for the side curtains and these envelopes neatly conceal the hood when it is folded away.
The release handle for the luggage locker lid can be reached behind the passenger seat; there is room in the locker for a suitcase and small articles. Strapped on the rear bulkhead is the tool roll, containing the lifting jack and wheelbrace. The jack, surprisingly enough, is of the old-fashioned screw type. A starting handle is supplied and is clipped to the back of the locker. Nine points require attention with a grease gun every 1,000 miles and the twin six-volt batteries are housed beneath the luggage locker. They can be reached by removing the spare wheel.
A heating and demisting unit, available as an optional extra, was fitted to the test car. It worked well, and draws in fresh air via a long duct through the engine compartment. On the left side of the radiator, fresh air is ducted to the intakes of the twin S.U.. carburettors. Hot air and fumes from the engine compartment are cleared by a vent on each side of the bonnet. As is usual with these B.M.C. engines, the oil filler is accessible, though it is difficult to see why the oil level dipstick could not be two inches longer, raising it clear of the sparking plug leads. Dynamo belt adjustment is not particularly easy with the standard tool kit.
Measurements in these ¼ in to l ft scale body diagrams are taken with the driving seat in the central position of fore and aft adjustment and with the seat cushions uncompressed
ACCELERATION: from constant speeds.
Speed Range, Gear Ratios and Time in sec.
4.3 5.908 9.520 15.652
tot tot tot tot
— 8.2. 5.0 —
12.2 8.0 4.8 —
12.3 8.4 — —
13.1 9.1 — —
15.0 10.7 — —
18.1 — — —
(normal and max.)
From rest through gears to:
30 .. .. 4.9
50 .. .. 11.0
60 .. .. 15.6
70 .. .. 21.4
80 .. .. 32.1
90 .. .. 50.1
Standing quarter mile, 20.2 sec.
SPEEDS ON GEARS:
Top .. (mean) 98.0
3rd .. .. .. 58—70
2nd .. .. .. 38—44
1st .. .. .. 20—26
TRACTIVE RESISTANCE: 20 lb per ton
at 10 M.P.H.
85 per. cent
77 per cent
58 per cent
(lb per ton) Gradient
303 lin 7.3
455 un 4.9
Pedal Pressure (lb) 100
27 m.p.g. overall for 672 miles (10.46 litres per 100 kin).
Approximate normal range 25—38 mpg. (11.3—7.4 litres per 100 kin).
Fuel, First grade.
WEATHER: Overcast, wet surface.
Air temperature 68 deg F.
Acceleration figures are the means of several runs in opposite directions.
Tractive effort and resistance obtained by Tapley meter.
Model described in The Autocar of September 23, 1955.
40 50 60 70 80 90 100
38 48 58 68 77 86 96
SPEEDOMETER CORRECTION: M.P.H.
Car speedometer 10 20 30
True speed: 11 20 29
PRICE (basic), with two-seater body, £595.
British purchase tax, £249 0s l0d.
Total (in Great Britain), £844 0s 10d.
ENGINE: Capacity: 1,489 c.c. (90.88 cu in).
Number of cylinders: 4.
Bore and stroke: 73.025 x 89 mm. (2.875 x 3.Sin).
Valve gear: o.h.v., push rods.
Compression ratio: 8.3 to 1.
B.H.P.: 68 at 5,500 r.p.m. (B.H.P. per ton laden 70.6).
Torque: 77.4 lb ft at 3,500 r.p.m.
M.P.H. per 1,000 r.p.m. on top gear, 17.0.
WEIGHT: (with 5 gals fuel), 171 cwt (1,904 lb), Weight distribution (per cent): F, 51.5. R, 48.5.
Laden as tested: 21 cwt (2,254 lb). Lb per c.c. (laden): 1.51.
BRAKES: Type: F, two-leading shoe; R; leading and trailing.
Method of operation: F, hydraulic; R, hydraulic. Drum dimensions: F, lOin diameter; 1 fin wide.
R, lOin diameter; lfin wide.
Lining area: F, 67.2 sq in. R, 67.2 sq in (112.6 sq in per ton laden).
Pressures (lb per sq in): F, 17; R, 20 (normal). F, 18; R, 23 (for fast driving).
TANK CAPACITY: 10 Imperial gallons.
Oil sump, 6f pints.
Cooling system, 10 pints (plus 0.65 pints if heater is fitted).
TURNING CIRCLE: 28ft 0 in (L and R). Steering wheel turns (lock to lock): 2f.
DIMENSIONS: Wheelbase: 7ft l0in.
Track: F, 3ft 1 ½ in; R, 4ft 0 ¾ in.
Length (overall): 13ft.
Height: 4ft 2in.
Width: 4ft l0in.
Ground clearance: 6in.
Frontal area: 13.77 sq ft (approximately) (with hood up).
ELECTRICAL SYSTEM: 12-volt; 51 ampêre-hour battery.
Head lights: Double dip; 42—36 watt bulbs.
SUSPENSION: Front, independent, coil springs. Rear, half-elliptic leaf springs.
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