Rover P4 - Engineering

Engineering

The cars used a Rover engine in 4- or 6-cylinder form which came from the 1948 P3 and had overhead valves for inlet and side valves for exhaust. A four-speed manual transmission was used with a column-mounted shifter at first and floor-mounted unit from 1954. At first the gearbox only had synchromesh on third and top but it was added to second gear as well in 1953. A freewheel clutch, a traditional Rover feature, was fitted to cars without overdrive until mid-1959, when it was removed from the specifications, shortly before the range rearrangements announced for the London Motor Show in October that year.

The cars had a separate chassis with independent suspension by coil springs at the front and a live axle with half-elliptical leaf springs at the rear. The brakes on early cars were operated by a hybrid hydro-mechanical system but became fully hydraulic in 1950. Girling disc brakes replaced drums at the front from 1959.

The complete body shells were made by the Pressed Steel company and featured aluminium/magnesium alloy (Birmabright) doors, boot lid and bonnets until the final 95/110 models, which were all steel to reduce costs. The P4 was one of the last UK cars to incorporate rear-hinged "suicide" doors.