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 minimum sparking speeds and leading distributor dimensions.
| Identifier | ExFiles\Box 40\2\ Scan105 | |
| Date | 24th April 1926 guessed | |
| - 3 - MINIMUM SPARKING SPEEDS. TIMING POSITION. Angle of Make 84° Angle of Make 90° Angle of Make 110° " Break 96° " Break 90° " Break 70° Adv: 55.r.p.m. 55.r.p.m. 50.r.p.m. Ret:30° 90 " 90 " 90 " " 60° 150 " 155 " 140 " ---------------------------------------------------------------------------------- LEADING DISTRIBUTOR DIMENSIONS. Rolls Royce suggested dimensions. Lucas type E.R.6. ---------------------------------------------------------------------------------- Dia .of track. - 2.4" 2.5" Pitch of track - 1.25" 1.30 Segment arc. - 0.80 0.80 Insulation arc - 0.45 0.50 Brush thickness - 0.25 0.20 Forward (Adv: - 0.125 0.13 Overlap (Ret: - 0.55 0.60. Backward (Adv: - 0.25 0.40. Overlap (Ret: - 0.175 - 0.05. | ||