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).
Secret memorandum discussing modifications to the ignition coil's position, mounting, and materials.
| Identifier | ExFiles\Box 69\1\ scan0011 | |
| Date | 1st October 1924 | |
| X8710 TO BY: FROM E.{Mr Elliott - Chief Engineer} SECRET. E1/M7.10.24. Copy to - O.J. [Struck through] Copy to - MPG. [Struck through] Copy to - HS.{Lord Ernest Hives - Chair} E.{Mr Elliott - Chief Engineer} A.{Mr Adams} C. 11. IGNITION COIL. X8710 As previously mentioned we have moved the position of the ignition coil, particulars of the modification being shewn on the attached drawing Lec. 1936. A number of advantages are thereby gained, such as the HT. main lead no longer is in contact with the metal portions of the engine, the original simple form of H.T. moulding on the distributor can be used, and the appearance of the engine is more orderly. Mr. Royce has fully approved of this drawing. It entails altering the material of the front cylinder head cover from cast iron to gun metal because of the magnetic effects in the neighbourhood of the coil, but we have taken advantage of this to delete the steel water pipe union and form the nipple on the cover itself. We do not think the temperature of the coil in this position should be any higher than in the old one on the wheelcase. Two schemes are shewn for the actual mounting of the coil, one in which heat flow to the coil case is guarded against by the use of pyroplax mouldings, and the other in which the coil is in contact with the bracket itself. The latter scheme being the simpler should be tried first, as it is only desired to use the former if found necessary. E.{Mr Elliott - Chief Engineer} | ||