História

The MGB’s performance was considered brisk at the time of its introduction, with a 0–60 mph (96 km/h) time of just over 11 seconds, aided by the relatively light weight of the car. Handling was one of the MGB’s strong points. The 3-bearing 1798 cc B-Series engine produced 95 hp (71 kW) at 5,400 rpm. The engine was upgraded in October 1964 to a five-bearing crankshaft in an effort to improve reliability. The majority of MGBs were exported to United States.

All MGBs (except the V8 version) utilized the BMC B-Series engine. This engine was essentially an enlarged version of that used in the MGA with displacement being increased from 1622 cc to 1798 cc. The earlier cars used a three main bearing crankshaft, 18G-series. In February 1964 positive crank-case breathing was introduced and engine prefix changed to 18GA, until October 1964, when a five-bearing crankshaft design was introduced, engine prefix became 18GB. Horsepower was rated at 95net bhp on both 5 main bearing and earlier 3-bearing cars with peak power coming at 5400 rpm with a 6000 rpm redline. Torque output on the MGB is good with a peak of 110 lb·ft (150 N·m) Fuel consumption was around 25mpg.

All MGBs from 1963 to 1974 used twin 1.5-inch (38 mm) SU carburettors.

All MGBs from 1962 to 1967 used a four-speed manual gearbox with a non-synchromesh, straight-cut first gear. Optional overdrive[7] was available.. This gearbox was based on that used in the MGA with some minor upgrades to cope with the additional output of the larger MGB engine. In 1968 the early gearbox was replaced by a full synchromesh unit based on the MGC gearbox.

There were three different types of overdrive transmissions fitted to the MGB.

1962-1964, 1965-1967

• Laycock Type D OD (note external solenoid)
• A hole in the bell housing where the starter nose pokes through
• “Shield” shaped access cover
• 1020 TPM for OD and 1040 TPM for non-OD

Note: The gearbox input shaft, flywheel and engine backing plate were changed with the advent of the 5 main bearing engine in 1965. Therefore, the transmission for a 3 main bearing engine (1962-1964) differs from its later counterpart 

Early MGBs used the “banjo” type differential carried over from the MGA with the rear axle ratio reduced from the MGA’s 4.1 (or 4.3) to 3.9 to 1. (Compensating for the reduction from 15 inch to 14-inch (360 mm) wheels.) MGB GTs first began using a tube-type rear axle in 1967.

All MGBs were fitted with 11-inch (280 mm) solid (non-ventilated) disc brakes on the front with drum brakes on the rear. The front brake calipers were manufactured by Girling and used two pistons per caliper. The brake system on the MGB GT was the same as the Roadster with the exception of slightly larger rear brake cylinders. A single-circuit hydraulic system was used before 1968 when dual-circuit (separate front and rear systems) were installed on all MGBs to comply with US regulations. Servo assistance (power brakes) was not standard until 1975. Many modern and contemporary testers have commented on the very heavy brake pedal pressure needed to stop the non-servo-assisted cars.

The MGB initially had an extremely simple electrical system. Dash-mounted toggle switches controlled the lights, ventilation fan, and wipers with only the direction indicators being mounted on a stalk on the steering column. The ignition switch was also mounted on the dash. Like the MGA, the MGB utilized two 6-volt batteries wired in series to give a 12-volt positive earth configuration. The batteries were placed under a scuttle panel behind the seats making access a bit of a challenge but the location gave excellent weight distribution and thus improved handling.

When leaving the factory all MGBs originally fitted Pirelli Cinturato 165HR14 tyres (CA67).

Combined production volume of MGB, MGC and MGB GT V8 models was 523,836 cars.

MGB Roadster
Production:
1962–1980 (399,070 made)

MGB GT
Production:
1965–1980 (125,282 made)

Motor sport

Specially tuned MGBs (including some made out of aluminium) were successful in international road competition events, scoring a Grand Touring category victory in the 1965 Monte Carlo Rally.[32] Circuit racing wins included the Guards 1000 miles race at Brands Hatch in 1965 and the 84-hour Marathon de la Route at the Nürburgring in 1966. MGBs also won the GT Category in the 1966 Targa Florio, the 1966 Spa 1000 and the 1967 Spa 1000.