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).
Modifying sparking plug gaps and increasing ignition coil secondary turns for 20/25 and 40/50 chassis.
| Identifier | ExFiles\Box 181\M13\M13.2\ img014 | |
| Date | 7th December 1930 | |
| EFC1/AM 7.12.30 contd. -5- hope to be able to revert to .030" sparking plug gaps on both 20/25 and 40/50 chassis. At the same time it may transpire to be necessary to increase the effective spark over voltage in the high tension distributor. It will be remembered that we used to have 21,000 secondary turns and even more -- the drop to 18,000 was made as it was found unnecessary to have this larger number of turns when the coil length was increased and further it was desirable to keep the circumferential space between the outside of the secondary and the inside of the coil case as small as possible from the point of view of the effect of leakage on and through the bakelite moulded cases. Now that this trouble can be said to be entirely eliminated there is no reason why we should not increase the available voltage from the secondary by increasing the number of secondary turns except apparently that of the limit imposed by the distributor head and the insulation of the coil secondary winding itself. EFC. | ||