Tests and Reports

Another interesting addition to the six-cylinder class is the 2-litre car exhibited by the Rover Company, in addition to its two four-cylinder models. This new car possesses several noteworthy features, as will be observed from the illustrations, Figs. 7, 8, 9, and 10. The engine has a bore of 65 mm by 101.5 mm respectively, giving a total capacity of 2023 c.c. and a Treasury rating of £16. The cylinders and top half of the crank case are cast en bloc, embodying the four bearings for the crank shaft and cam shaft. The valves are of the unorthodox overhead type operated by push rods from the cam shaft, the latter being driven by a silent chain from the rear end of the crank shaft.

The construction of the detachable cylinder head is unusual, in that the combustion chambers are formed in the cylinder barrels, and the underside of the cylinder head is flat, the sparking plug holes protruding angularly into the combustion chambers. Aluminium pistons having two rings in the head and a scraper in the skirt are employed. Ignition is by battery and coil, the distributor being driven through a long vertical shaft by skew gears, from the front end of the camshaft. The distributor is in a readily accessible position at the front of the engine on the near side and also on the same level as the valve cover. The manner in which the power unit is carried in the frame is novel.

Three-point suspension is adopted, the single point at the front end consisting of a short beam screwed into the front end of the cylinder crank case casting and supported on a plate attached to the front cross member of the chassis. A flexible mounting is provided for the unit at the rear end, two extension arms on the fly-wheel housing are connected to stiff laminated four-leaf springs bent to fit round the outside of the chassis members. A bolt passing the extension arm between them completes the flexible mounting.

The lubrication is by means od a gear type pump - Fig.10 - situated in the aluminium sump and driven from the cam shaft by skew gears. From the pump the oil is forced through a filter bolted to the outside of the crank case, and easily removable for cleaning, to the cam shaft and crank shaft bearings. The big end bearings are supplied with oil through the drilled crank shaft. Following the latest Rover practice, the engine, clutch and gear-box are lublricated by a common system, oil being forced down the hollow crank shaft through the hollow clutch shaft and into the main shaft of the gear box, where a constant level is maintained, the overflow being returned to the sump. No less than three gallons of oil are continually circulated in this system, the sunp alone holding two gallons. Oil is also taken from the rear end of the crank shaft to the cam shaft drive and by an external pipe to the hollow rocker shaft, a certain amount of this oil being by-passed to a cannister type of oil filter situated on the front of the dashboard. This filter is of a common type and is not cleanable, but is intended to be renewed about every 12,000 miles. The ball cup joints at the top of the push rods are supplied with oil by channels cut in the rockers, the latter being supplied from the hollow rocker shaft.

Cooling is by an impeller type pump housed in the forward end of the cylinder head and driven by Whittle belt from a pulley situated at the front end of the crank shaft. This pulley also houses a Lanchester vibration damper- Actually there is no water connection to the cylinder block, the top connection to the radiator being taken from the thermostat arranged at the rear end of the cylinder head. The inlet and exhaust manifolds are situated on the near side and so arranged as to heat the ingoing charge from the twin Zenith carburetters, the latter being fed by vacuum tank from a 12-gallon tank at the rear of the chassis.

The clutch and centrally controlled gear-box form a unit with the engine. The clutch is of the cork-insert pattern, having three separate aluminium plates running in oil. Auxiliary springs are interposed between the plates to ensure disengagement of the free members when the oil is cold. From a cross pin type of universal joint at the rear of the gear-box the drive is taken through an enclosed propeller shaft, having a centre bearing to a spiral bevel rear axle. The arrangement of the worm and segment steering gear is uncommon. A bracket carrying a vertical shaft is bolted to the off side of the crank case, the steering box being situated at the top of the shaft and the drop arm, to which the drag link is attached in the normal manner, at the bottom. In this arrrangement the drop arm moves in a horizontal instead of a verticval plane as is usual. This construction provides a well-raked steering column, thus giving a comfortable driving position.

The chassis frame is of normal construction, being parallel at the front and rear and tapering amidships. It has four cross members and is braced by diagonal members running from the centre cross member to the forward points of attachment of the rear springs. Semi-elliptic springs are used front and rear, the ends of the second leaves being carried round the eyes of the shackles. Shock absorbers are fitted all round. The front axle is of circular section and brakes are fitted to all four wheels. Rhe foot pedal operates on shoes within all four wheels and the centrally placed hand lever on those in the rear wheels only. The four-wheel brakes are provided with an accessible master adjustment. A 12-volt Lucas starting and lighting equipment is fitted. The starter is accessibly placed on the off side of the engine and is carried in a housing integral with the crank case. Theree types of body work are fitted to this chassis.