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).
Experiments to improve ignition timing by altering spark gaps and advancing the distributor rotor.
| Identifier | WestWitteringFiles\D\October1919\ Scan32 | |
| Date | 24th October 1919 | |
| Contd. -4- EFC10/T24.10.19. Other things being the same, opening up the spark gaps to, say, .020" or .025" introduces a tendency to miss fire. There would also be a tendency to miss fire if the rotor were timed too late, so that although the gaps, when the rotor is passing the contact point, are right, there exists a gap between the leading corner of the rotor and the stationary contact point, at the instant of break, over which the spark has to pass. We have experimented to ascertain if such missing due to the rotor being timed a little late, is merely due to the increased gap resulting from that condition, or if there is some other factor in the distributor apart from this, and we are of the opinion from such experiments that it is not only a question of gap, but there is really some advantage gained by advancing the rotor, as we carefully compared two cases in which the actual gaps over which the sparking had to occur were the same, but in one case of which the rotor was more advanced than in the other, and we found the latter condition to be, if anything, preferable to the former. We therefore have asked the production D.O. to put through an alteration to the rotor which will advance the distributor so that when break takes place .010" of the periphery of the rotor has already passed the contact point. This alteration is now well in hand. (3) Nos. 1 and 2 are improvements which can comparatively easily be carried out on production chasses. No. 3, however, cannot so readily be done. This consists in the use of a high tension wire run from the coil to the central terminal Contd. | ||