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).
Graph comparing engine performance curves (BHP and BMEP) against RPM for three different inlet valve timing configurations.
| Identifier | ExFiles\Box 92\2\ scan0145 | |
| Date | 9th August 1931 guessed | |
| COMPARISON OF VARIOUS INLET VALVE DURATIONS RM.{William Robotham - Chief Engineer} P.23 4.78 C/R.{Sir Henry Royce} OPEN EXHAUST STD ALUM HEAD RR TWIN CARBS 1-4" CHOKES. 1.5 DIA VALVE THROAT .013 TAPPET CLEARANCE Diagram A: VALVE LIFT .490 IN/EX timing: 26, 66, 23, 67 SCH 1069 Diagram B: VALVE LIFT .470 IN/EX timing: 3, 58, 12, 54 LEC 2918 Diagram C: VALVE LIFT .430 IN/EX timing: 51, 54 SCH 1053 Graph Axes: Left Y-axis: B.H.P. (80-170) Right Y-axis: INDUCTION DEPN. INS HG (0-4), B.M.E.P. LBS/SQ" (60-120) X-axis: R.P.M. (500-3500) Graph Data: INLET THROAT DIA 1.9" INLET DURATION 272° " LEC 2918 241° " STANDARD 223° Curves labeled A, B, C correspond to the diagrams. | ||