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).
Test report on magneto timing, endurance, and performance comparison of various models.
| Identifier | WestWitteringFiles\F\February1921\ Scan79 | |
| Date | 21th December 1931 guessed | |
| Contd. -4- EFC4/T3.2121 The breaks occurred as follows :- Advanced 94º, 99.5º, 79º after datum Retarded 130.5º, 137º, 115º after datum. The periods of make respectively are therefore 82.5º, 153º and 157º. The R.{Sir Henry Royce} Bosch is the only magneto so far investigated with long cams and short period of make, the Watfords being similar to the U.S.A. Bosch machines in this respect. The timings etc. given are the averages of the two sides. We found the above gaps and timing to be immaterially altered after our running tests and the timing to be very little affected by varying the platinum point gap ± .004". (7) The next item on our schedule consists of a short (12 hour) endurance test at 2000 R.P.M. sparking on a set of six 5.5 mm. gaps with timing lever central. This is the first running test, the idea being to eliminate magnetos which show any signs of trouble or failure, before the remainder of the investigation is carried out. On the R.{Sir Henry Royce} Bosch Z.R.6, the contact points slightly blackened. There were only slight signs of tracking in the distributor cover. The contact breaker lever fibre did not wear appreciably. On the U.S.A. Bosch Z.R.6 there was a fine deposit of carbon dust on the distributor segments and the contact breaker points were slightly burred, otherwise both these machines ran very well. The U.S.A. B6 magneto did badly on this test . The | ||