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).
Service issues with American Bosch magnetos and battery ignition systems, and proposing switch design improvements.
| Identifier | ExFiles\Box 31\2\ Scan059 | |
| Date | 8th March 1923 guessed | |
| Oy2-W-22023 -2- We have fitted American Bosch magnetos since car 26, i.e., on 400 cars, and American Bosch battery ignition since 176, i.e., 250 cars. On magnetos we have had about three cases of demagnetising in service (probably caused by running grounded), six cases of points developing great gap through wear of the fiber bush or hammering of points, and three cases of points coming off. On battery ignition our sole trouble in service so far has been one ballast resistance burnt out. We have virtually no "overoiling" so-called, of plugs, because of feeding fairly clean mixture into the engine. No case of pre-ignition, and very few cases on test or service of a defective plug. (Plug Champion A 63). The prevalent cause for loss of battery ignition is the grounding fuse going, generally through blowing the horn a lot on a cold morning with the oil cold. Since this puts the horn out as well the cause is obvious. See wiring diagram A-1232 attached. If the battery fuse goes, I agree it is likely to escape detection, but since this rarely occurs, I do not think it justifies the complication, mystification, and messing-up of the instrument board, caused by a second switch. The most that I think is necessary is an intermediate position on the switch handle, without a "click" (preferably an "unstable" position which has to be held by hand) giving battery only. This we are attempting to secure on our new switches. Nadin also has made the very good suggestion of a further unstable position of the switch lever beyond the "on" position which shall give "magneto only". These could easily be secured on the central switch and might be marked "Bat. Test" and "Mag. Test" on the face of the switch. Oy. M.{Mr Moon / Mr Moore} Olley | ||