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).
Series of tests to determine the optimal sparking plug gap to overcome engine misfiring.
| Identifier | ExFiles\Box 58\2\ Scan049 | |
| Date | 22th June 1932 | |
| X1812 C. To Hs.{Lord Ernest Hives - Chair} from G.H. Whyman. c. to Rn.{Mr Robinson} Ltd. 22.6.32. We have now completed a series of tests to determine at what gap we can set our sparking plugs on the magneto side to overcome misfiring. Chassis No. 215-AMS. - borrowed from the Test Dept. Plugs misfire picking up at .025", .020" and very occasionally at .018", but no misfires whatever at .015" gap. The magneto No. 126887 was then taken off and No. 130540 fitted. - The same results were obtained. Chassis No. 214-AMS. The next chassis we tried was 214-AMS, and the plugs misfired picking up when set at .025", .020", .018", very occasionally at .015", but not at .012". There were slight misfires, however, at very slow speeds, that is 4 to 5 m.p.h. with gap set at .012". The magneto No. 126900 was then taken off and No. 130540 fitted. With this magneto fitted there were no misfires either picking up or at slow speeds with the gap set at .015". Hs{Lord Ernest Hives - Chair}/G.H. Whyman. | ||