From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Technical specifications for the Supercharger, Valve Gear, Gearbox, and Axles.
| Identifier | ExFiles\Box 179\3\ img028 | |
| Date | 3rd March 1932 | |
| -2- He/Oxy.3/WJ.3.3.32. Cont'd.{John DeLooze - Company Secretary} (b) Supercharger. A Rootes type blower sucks from a double Nemini carburetter. For details see separate report. (c) Valve Gear. The inclined valves are operated by two overhead camshafts. The camshafts end in steel helical gears and are both driven by a dural gear which is on a shaft with the spiral bevel driven by the vertical drive. Each camshaft has a spring applied brake the effect of which is lessened centrifugally by the brake consists of bronze blocks rotating with the camshaft held by single leaf springs on to a stationary drum (See sketch). The torque of the brake is 18 lbs. ins. and it will cease to operate at 5400 RPM. Each camshaft runs in five bronze bearings. The cams act directly on to the top valve spring washer. This washer also provides the tappet adjustment by screwing up or down the valve stem. The moving parts are very light, the weight of the valve and top washers being .232 lbs. The double valve springs of the low stress range type give together 31 lbs. with the valve on the seat and 43 lbs. valve open. The valve lift curves show that the valve is most likely to bounce at a lift of .225 giving a calculated bouncing speed allowing for no suction on the valve of 5400 RPM. and allowing for 10 lbs. suction at 4500 RPM. (2) GEARBOX. This is unit construction with the engine. The casting is aluminium and inside a cover at the bottom of the gearbox is the brake compensating gear. There are four forward speeds of ratios 1:1, 1.32:1, 1.905:1, and 3.06:1. The shaft centre distances are 2.625 and the gears 8.4 D.P. The side shaft runs in two ball races; the first and third motion shaft have each one ball race, the spigot bearing being a plain bronze bush lubricated by holes drilled at the root of the teeth of the constant mesh gear. (3) AXLES. (a) Rear. The rear axle is mounted on saddles on the underslung semi-eliptic springs. These are shackled at both ends, the torque being taken by a torque tube. The axle ratio is 12/51 giving 3180 RPM. at 60 M.P.H. The gearing in spiral bevel and the half shafts take the weight of the car. The casing of the banjo type consists of two pressings welded top and bottom along the axis. The whole differential assembly is drawn out with the back cover. There is a steady race in the middle of the propeller shaft. | ||