Technology

As we have only little information about the technology of the ROVER 15hp, we reproduce here the fair report on the 1908 Olympic show from The Motor Car Journal from 21 November 1908.

The Rover Automobiles

For the 1909 season the ROVER COMPANY, LTD, Coventry, are turning out no less than five models - viz. 6hp, 8hp, 12hp, 15hp and 20hp. Except for detail improvements the 6hp and 8hp models, which are fitted with single-cylinder engines, remain on similar lines to those of the past year. The 12hp car is fitted with a two-cylinder engine and a three-speed gear-box, and is designed to receive a four-seated touring body, access to the rear seats being obtained by swinging round half of the front seat. The novelty at the stand is the new Rover 15hp car, which has many points of interest. The cylinders of the four-cylinder engine (85mm bore by 110 mm stroke) are cast in pairs, with the valves all on one side. With trhe view of rendering the motor as quite as possible, the valve stems and tappet guides are enclosed by large detachable plates. Ignition is by coil and accumulators, provision being also made for the installation of a magneto; the lubrication is controlled by a pump, which forces the oil to all the main bearings. A feature of the motor is that it is designed to be used as a brake in descending steep hills. The cam shaft is of special design, and, in addition to lifting the inlet and exhaust valves in the usual way, is so constructed that it can be used to effect an engine or compression brake. By moving the cam shaft in longitudinal direction by means of a pedal, the inlet valves are kept closed, while the exhaust valves are lifted twice to every revolution of the shaft, whith the result that air is taken in from the exhaust pipe on every downward movement of the piston, compressed on the upward stroke, and then exhausted. The inlet valve being permanently closed, no gas is admitted to the combustion chamber, whith the result that the engine is working under compression, which effectually retards its movement, and at the same time it is being cooled. The arrangement has proved so effective in practice that is is claimed to be sufficient to hold the car, when the low speed is engaged, on almost any hill. The engine and gear-box are bolted together to form a unit. The clutch is of the Rover plate type, with easy means of adjustment. The gear-box is adapted to give three speeds, with direct drive on the top of the rear axle, to the design of which has special care has been directed. The frame is supported on four semi-elliptic springs. The 20hp car, which has a three-point suspension, shows but little change from last year. Fig. 51 shows the change speed quadrant, now employed on this model, as also on the 8hp Rover. It will be seen that, in addition to the ordinary slots corresponding with the respective gears, a stop is placed on the opposite side of the quadrant in order to prevent the incautious driver passing the desired gear. The lever itself is hinged near its fulcrum, and provided with a coil spring, the latter holding the lever to the gear notches. The slightest pressure sideways is sufficient to overcome the spring, when the lever can be moved along until arrested by the stop, when it automatically slips into the gear notch required.