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).
Specification sheet for ignition system components and timing.
| Identifier | ExFiles\Box 49\5\ Scan219 | |
| Date | 10th December 1920 | |
| -2- Contd. (4) Length of h.t. safety gap (inches) :- .335 * * * * * (mm) :- 8.5 (5) Distributor :- Total pitch :- 1.477" Conductor width :- .895" Brush width :- .300" Position of brush at break (advanced) :- 20" * * * * * (retarded):- 46" (6) Platinum point gap :- .016" Contact breaker timing :- Retarded Advanced. Make. Break. Make. 157° 122° A. {Mr Adams} -58° +98.5 Break. 314° 279° R. {Sir Henry Royce} -23° 133.5 Make. 337° 302° Break +133° +98° range :- 35° Make ratio :- .870. | ||