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).
The testing and performance of an oil ignition relay device.
| Identifier | ExFiles\Box 65\1\ scan0045 | |
| Date | 31th December 1924 | |
| X. 8685 To Hs.{Lord Ernest Hives - Chair} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}/LG31.12.24 OIL IGNITION RELAY. This device is now a reasonable working proposition. The aluminium piston fitted has a clearance of .007". This we consider to be the maximum permissible if the oil relay is to function reasonably well under reduced oil pressure. Attached are curves shewing the ignition advance curve obtained with this piston clearance when the oil relay is heated up by steam and oil pressure is very considerably reduced. From tests we have made we consider that this piston should work under all conditions of oil viscosity likely to be encountered on the car, although round about freezing point there will be a considerable lag in its operation. We cannot say whether grit in the oil will cause it to stick in practice: we have not had one stick up as yet. It will be seen that the curve we have obtained under normal working conditionsof oil pressure and temperature, with the hand control in the fully advanced position, differs only slightly from the specified curve when the governor springs are set as at present. At no point is the curve we obtain outside the limits of ignition advance required by the engine for maximum power. The serrated magneto adjustment is still a source contd :- | ||