Page 37 - Wayne Carini's Guide to Affordable Classics

1500
The first models on the market were the MGA 1500s, produced from 1955 to mid-1959. The roadsters were by far more popular, with 52,478 produced and sold, compared to just 6,272 coupes. MG knew the market for this car was in America, and 43,663 roadsters and 4,768 coupes were produced to North American spec.
The engine in the MGA 1500 is the 1489 cc BMC B-Series. This is a pushrod overhead-valve four-cylinder, outfitted with two SU 1.5- inch H4 sidedraft carburetors, a Lucas distributor, and a generator. First-year cars were rated at 68 horsepower and 77 lb ft of torque, rising to 72 horsepower and 77.4 lb ft for 1957 and later. The BMC engine is known as a hardy unit that responds well to a more aggressive cam profile, compression increases, and head porting.
The basic engine was mated to a four-speed direct-shifting manual transmission. First gear is unsynchronized and fourth gear is a 1:1 ratio connection. The standard final drive was 4.3:1 with an open differential, but a 4.55:1 ratio was available as an option for those who wanted to trade a little top speed for better acceleration. The driveline gave a new MGA a 0-60 time of about 14 seconds, and a top speed of about 93 mph.
MG MGA
On the greasy side of the car, the front suspension used upper and lower A-arms with a coil spring. However, the upper A-arm was part of an Armstrong lever-arm shock absorber. Sway bars were not included, but the MGA used precise rack and pinion steering. At the rear, a traditional solid rear axle housing was mounted on semi-elliptic leaf springs. Lever arm shocks mounted high up in the body damp rear suspension motion using drop links. From the beginning of production through April of 1959, drum brakes were installed at all four corners. Steel wheels were standard, but center-lock wire wheels were optional.
Twin Cam
From 1958-1960, MG produced a special high-performance MGA variant called the Twin Cam. Both roadsters and coupes could be purchased with an enlarged B-Series engine, uprated to 1588 cc and equipped with an aluminum head featuring hemispherical combustion chambers and a double overhead cam valvetrain. Twin 1.75-inch SU carburetors helped the Twin Cam engine produce 108 horsepower and 104 lb ft of torque. The Twin Cam transmission used close-ratio gears and a 4.55:1 rear axle ratio, yielding about 9.9 seconds for 0-60 and a top speed of at least 115 mph. The Twin Cam also received Dunlop disc brakes at all four
The initial version of the MGA 1600 was an undeniably better vehicle than the smaller-engined version that it replaced with much better performance available under the hood.
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