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).
Design considerations for engine components including the cylinder block, pistons, and crankshaft.
| Identifier | WestWitteringFiles\Q\July1927-September1927\ Scan131 | |
| Date | 15th September 1927 guessed | |
| (3) (6) CYLINDER BLOCK. The cylinder blocks will be in cast iron, with three small round covers on one side, and one square long one on the other side. These covers will be in aluminium alloy, of a variety which has been proved non-corrosive from water. It is suggested that the jointing material for the large cover might be cork, and perhaps for the small covers rubber insertion might be used. (7) PISTONS. In consequence of the high speed it is advisable that every fraction of weight shall be removed from the pistons, connecting rods, and crankpins, and we believe we can reduce the present piston very materially by using the single bolt pedestal type in wrought 'Y' metal, and also by reducing the number of rings, fitting a duralumin or other light metal little end bush, and reducing the out of balance weight to the very minimum. The reason we expect to run satisfactorily with less piston rings is due to the discovery of the distortion of the cylinders, which can be prevented by the improved [strikethrough] process of honing: this produces a cylinder bore which is more exactly circular than parallel. (8) CRANKSHAFT. Regarding the crankshaft we do not expect to do very much to this at the moment, but we may bore out the pins, or reduce their diameter in the near future, but we are very anxious to fit to the front end of the engine the G.1. type of friction damper. The designs for this we expect will take not more than two or three days, but we feel it is necessary for the car to wait for this item before leaving for its 10,000 miles trial. It can soon be found whether it is hopeful as an improvement by its behaviour on the India 3. engine at present in the hands of Derby. (9) CLUTCH. Regarding the clutch, it will be remembered that we have reduced a few of the parts to greater simplicity, and have doubled the effectiveness of the clutch brake, which is found by experience and calculation to stop the clutch very much slower than the Silver Ghost type. (10) VALVES. Regarding the valves it is understood that we must continue to use the felt gland on the inlet valves, and perhaps on both, and to get the engine right for 3000 RPM. it is necessary to use stiffer valve springs, the designs for which will leave WW. probably tonight,(the 15th inst.) these springs being the | ||