The V8 - the MG with effortless performance
Launched in August 1973, the V8 powered MGB combined the popular fixed head coupe body style with a powerful three and half litre light alloy V8 engine. The Rover powerplant ran with a reduced compression ratio but an increased torque compared with the similar engines then used in the Rover saloons. The result transformed the MGB, creating a very nimble car with the luxury of multi-cylinder power which is both flexible and economical - features which continue to have a special appeal for V8 enthusiasts today!
On the road the MGBGTV8 has an effortless performance, accelerating rapidly in the higher gears with 125 mph available in both direct and overdrive top. Hills just melt away and the torque gives the car an unfussy manner. The 0 to 60 time of 7.7 seconds is still 30 years later, a time many of today's sports saloons cannot touch. Even when asked to work hard, the exhaust note retains its very pleasingly modest but purposeful burble in keeping with its understated manner.
The V8 engine, although from an old Buick design from the early fifties, contains hydraulic cam followers which give the MGBGTV8 a quietness that compliments the smooth power. Under the bonnet, the lightweight aluminium V8 engine seems much bigger than the original four cylinder steel engine but is only just a little heavier when the engine ancillaries are included. The lightweight benefits are good front to rear weight distribution and an appreciable increase in the power to weight ratio, even from the detuned 137 bhp V8 power unit.
A surprising feature of the MGBGTV8 is the fuel economy. Even driven on the open road with a sense of fun the enthusiast can enjoy with V8 power, it is quite easy to achieve between 27 and 31 miles to the gallon. The overdrive unit gives the MGBGTV8 long legs with around 29 mph per 1,000 rpm or 3,000 rpm at 90 mph. The convenient overdrive facility is available on top gear at the flick of a stalk switch on the steering column and on many of the earlier chrome bumpered examples of the model, it is available on third gear as well.
The MGBGTV8 is however not without its poor features - excessive wind noise at speed and a choppy ride at slow speeds from the stiffer rear springs which are needed to cope with the higher power output. The gearbox has to be treated with consideration when punching the additional power through to the road wheels.
At its launch in 1973, the MGBGTV8 was welcomed as a powerful example of the MG marque but generally regarded as arriving several years late in a popular but ageing bodyshell and suspension package, then over ten years old. The MGBGTV8 is very much an MG combining the famous marque's Safety Fast! features - speed and performance with predictable and forgiving handling characteristics. At the time of the launch, the specification of servo assisted brakes, tinted glass, distinctive light alloy wheels, fine cord covered adjustable seats, two speed wipers and an overdrive as standard made it a refined sports car for 1973 and good value at its launch price of £2,294. In so many ways the MGBGTV8 is an undiscovered classic sportscar and prices have never been driven up by "chequebook investors".
|Engine type||Rover 3.5 litre V8|
|Location & drive||In-line front with rear wheel drive|
|Number of cylinders||8|
|Layout||90 degree Vee in two banks|
|Bore||3.50 in (88.90 mm)|
|Stroke||2.80 in (71.12 mm)|
|Compression ratio||8.26 : 1|
|Firing order||1, 8, 4, 3, 6, 5, 7 , 2|
|..left bank||1, 3, 5, 7|
|..right bank||2, 4, 6, 8|
|Idle speed||800 to 850 rpm|
|Fast idle speed||1,400 to 1,500 rpm|
|Oil pressure - normal||30 to 40 lb/sq in (2.0 to 2.8 kg/sq cm)|
|Cylinder head||Aluminium alloy|
|Cylinder block||Aluminium alloy|
|Valve gear||Single cam with two valves per cylinder|
|Maximum power output||137 bhp at 5,000 rpm|
|Maximum torque||193 lb.ft at 2,900 rpm|
|Timing at 1,000 rpm||8 degrees BTDC|
|Timing marks||On the crankshaft pulley pointer attached to the front of the cylinder block|
|Dwell angle||28 degrees|
|Contact breaker gap||0.014 to 0.016 in (0.35 to 0.40 mm)|
|Spark plug type||Champion L-92Y now NGK 4111 BP5HS|
|Spark plug gap||0.035 in (0.90 mm)|
|Fuel system||Twin SU HIF6 carburettors|
|Recommended octane rating||94 RON minimum|
|Carburettor spring colour||Yellow|
|Fuel pump||SU type AUF305 electric|
|Circuit polarity||Negative earth|
|Batteries||Twin 6 volt, later one 12 volt|
|Capacity (20 hour rated)||67 amp hour|
|Fuses||35 amp (blow rating)|
speed, all synchromesh gearbox with reverse. Laycock overdrive on third
and fourth gears on the early cars and on fourth only on cars from around Car No. GD2D1 1400
|First||3.138 : 1|
|Second||1.974 : 1|
|Third||1.259 : 1|
|Fourth||1 : 1|
|Overdrive||0.82 : 1|
|Fourth gear speed per 1,000 rpm||23.0 mph (37 kph)|
|Overdrive top speed per 1,000 rpm||28.5 mph (45 kph)|
Rack and pinion with collapsible steering column. Turning circle 34 ft (10.36 m) left lock and 33 ft 1 in (10.1 m) right lock.
Independent with coil springs and lower wishbone mounted on a crossmember assembly. Lever arm shock absorbers with double levers carrying the top end of the swivel pin. Anti-roll bar.
Tube type live axle with three quarter floating drive shafts. Semi- elliptic multi-leaf springs. Lever type shock absorbers.
Front: 10.7 in (272 mm) diameter solid discs. Rear: 20 in (254 mm) diameter drums. Servo assisted hydraulic.
Wheels and tyres
|Wheel size||5J x 14|
|Wheel nut tightness||60 lbf.ft (8 kgf.m, 81 Nm)|
|Tyres size||175HR x 14|
|Tyre type||Radial ply|
154.75 in (3,931 mm)
Rubber: 158.25 in (4,020 mm)
|Overall width||59.94 in (152.3 cm)|
|Overall height||49.97 in (126.9 cm)|
|Ground clearance||4.25 in (108.0 mm) minimum|
|Track front||49.0 in (124.4 cm)|
|Track rear||49.25 in (125 cm)|
|Wheel base||91.125 in (231.5 cm)|
|Fuel tank||12 gallons (54 litres)|
and oil cooler, refill with filter change. Filter 0.5 pint
|8 pints (4.54 litres)|
|Gearbox and overdrive||6 pints (3.4 litres)|
|Rear axle||1.5 pints (0.85 litres)|
|Cooling system with heater||16 pints (9.08 litres)|
|Windscreen washer bottle||3 pints (1.71 litres)|