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).
Comparing the lifespan and performance of different magneto and battery ignition contact points.
| Identifier | ExFiles\Box 35\6\ scan 247 | |
| Date | 16th February 1927 | |
| To R.{Sir Henry Royce} from EFC. c. to EJ. E.{Mr Elliott - Chief Engineer} c. to BY.{R.W. Bailey - Chief Engineer} Wor.{Arthur Wormald - General Works Manager} Y2894 EFC3/LG16.2.27. LIFE OF MAGNETO AND BATTERY IGNITION CONTACT POINTS. X4652 to X8793/b We have no experimental evidence to the effect that Lucas magneto contact points last appreciably longer than those of other magnetos, but our evidence is limited to the case of one magneto of this type only. Experiments on later Lucas magnetos received are in abeyance with the exception of one which you have on 7-EX which had done 660 miles at the time you received the car. Enquiry reveals that the points of Watford E06 magnetos on customers cars last particularly well - there are very few complaints, though we have had one or two cases apparently of early failure (exact record not kept) on experimental cars. Current reversal is so helpful on platinum point life that it appears that the life of magneto points can hardly be taken as a criterion of that of B.I. points. In nearly every clean (free from oil) case on our own B.I. a pip forms on the lever point and a hollow on the screw point. This effect continues to grow until the platinum pip reaches the iron of the screw point when mis-firing begins. Tungsten points do not do this seriously but become oxidised, while sometimes causes missing. On the whole we are now almost coming to the conclusion that tungsten points would be better because the material is not lost or transferred so rapidly and the points can therefore be re-faced more often. The impending 10,000 miles test on experimental chassis 10-G-3 will provide us with evidence on which to base a decision re. standardisation. In the meanwhile we are awaiting the new design of contact breaker. EFC. | ||