The Rover 8 was a small single-cylinder eight-horsepower 1327 cc car made by the British Rover car company. It was Rover's first production car. It was remarkable for being supported by a backbone chassis rather than a conventional ladder frame. The first model was manufactured from 1904 to 1912, A Daimler-Knight sleeve-valve engine option was available in 1911 and 1912. Following World War I a new 998 cc twin-cylinder eight-horsepower light car was offered from 1919 to 1925. It was in its turn superseded in 1924 by a four-cylinder 1074 cc Rover 9.
1904-1912
The car, designed by Edmund Woodward Lewis who had joined Rover from Daimler, had an unusual structure. Instead of the conventional chassis, the car had a backbone structure, formed by the engine crankcase, the gearbox housing, a rigid tubular propellor shaft housing, and the rear axle housing; the whole described as having a box girder section. The backbone frame, without bump-compliance at the rear apart from the tyres, was suspended from the front axle at just one point by a pivoted transverse leaf spring which made no contribution to transverse rigidity, and thus the whole remaining car rested on just three points, similar to the design of old, four-wheeled farm tractors. The body, through its own sub-frame, was mounted on the rear axle using semi-elliptic springs. The single-cylinder engine displaced 1327 cc with a bore of and stroke of. Its inlet and exhaust valves were both mechanically operated.
Engine braking
It had an unusual pedal control that changed over the valve operating cams to provide extra engine braking. When it was wished to slow the engine a driver's foot lever moved the cams first to reduce valve lift and then second, on further pressure, the valves are closed completely and the engine is effectively an air compressor slowing the rear wheels.
Trial by The Autocar
Autocar's staff drove the 2-seater car for ten days covering some 400 miles. The control turning the engine into an air brake is sufficient for most purposes and the double band brakes are only needed for the steepest hills or an emergency stop. Turning the car at a very sharp angle puts greater tension on the ignition or throttle control and the engine speed is upset. The car has a good turn of speed and climbs extremely well hills. Since introduction modifications include removing the gearbox casing from its part in the car's backbone, improved gear changing and better access for the carburettor.
Frame change
By 1907, Rover had discontinued the backbone frame and was using an ash chassis with steel flitch plates. Robert Jefferson and Robert Weallas drove a Rover 8 from Coventry to Istanbul, becoming the first people to cross Europe in an automobile. Most of this series of Rover 8 cars seem to have had a very basic open two seat body with no windscreen or other weather protection. At launch the Rover 8 cost £200 on the home market.
Sleeve-valve engine
In 1911, the Rover 8 was offered with a 1052 cc sleeve-valve unit. Daimler built the Daimler-Knight sleeve-valve engine. The cars with the sleeve-valve engines used the long-wheelbase chassis with the larger dimensions.
1919-1925
The Rover 8 light car announced in October 1919 was designed by Jack Sangster largely before he joined Rover. Built in a new factory in Tyseley, Birmingham it was driven to Coventry to have its body fitted. It was a great sales success for the company. The air-cooled, side valve, engine was a horizontally opposed twin and was originally of 998 cc capacity, with a bore of 85 mm and a stroke of 88 mm, but this was increased to 1134 cc with a 100 mm stroke in 1923. The original engine had a peak output of at 2600 rpm. Although there was a conventional looking radiator it was a dummy. Cooling was supplied through air scoops on the side of the bonnet and it was rumoured that after hard driving at night the cylinder heads could be seen glowing red through them,. Two cross-members of the frame supported at three points the assembled unit of engine and clutch and a three speed gearbox with reverse. The rear wheels were driven through a fabric joint and propellor shaft to a universal joint and an under-worm wheel type rear axle. A dynamo was belt driven from the propeller shaft. An electric starter was optional from 1923. A six volt lighting set was provided. The chassis was a simple perimeter frame with quarter-elliptic leaf springs all around. This cantilever springing and the rack and pinion steering were both regarded as unusual at the time. Wheels were steel and detachable. Brakes were fitted to the rear wheels only with a separate set of shoes for the handbrake. The wheelbase was extended from to in 1924 to allow genuine four seat bodies to be offered including a fabric four seat saloon. Open two seater bodies with dickie seats were usual but an open 3 or 4-seater body was shown at the October 1922 Motor Show on a wheelbase six inches longer at 94 inches and a few closed 2 seater coupés were also made from 1923 as well as light commercials. The car cost £230 in 1919, but was reduced to £139 by 1925. It could attain and could return 45 miles per gallon. Optional extras included: non-standard colour £5, speedometer £7, side curtains to hood completely enclosing the body £3. In November 1921 engine lubrication was improved and the body given more room inside. Its shape's appearance was also improved. Improved valves were fitted from October 1922 made of special steel to remedy over-heating. The Rover 8 was made under licence in Germany, with a slightly larger engine, by Peter-und-Moritz between 1921 and 1923.
The motoring correspondent of The Times reported in October 1922 the car's road manners were an agreeable surprise, it was astonishing how little one missed the other two cylinders. There was no speedometer but the maximum on a level road seemed to be about 40 mph. Seating was comfortable with adequate room all round. A driver's side door was missed. Altogether a great little car.
