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).
Performance graph comparing large and small valves.
| Identifier | ExFiles\Box 13\2\ 02-page137 | |
| Date | 26th August 1931 | |
| RM.{William Robotham - Chief Engineer} P.15 COMPARISON OF LARGE & SMALL VALVES 4.78 C.R. W.W. 1 1/4" SHAFT LE G.2818 OPEN EXHAUST NS.{Norman Scott} DEPN. 3000 R.P.M. LARGE VALVES C DENOTES CLAUDEL 1.90 T TWIN CARB. 1.4 DIA. CHOKE 2.55 B.H.P. B.M.E.P. LBS./□" R.P.M. ① INLET VALVE THROAT 2.00 TREPANNED ROUND PORTS ② INLET VALVE THROAT 1.580 30° SEAT Hs.{Lord Ernest Hives - Chair}372 Valve Timing Diagram: Ex In 10 5 52 61.8 .013 CLCE. Graph Curves: ①c ②c ①T ②T 26/8/31 | ||