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 engine valves based on BHP and BMEP against engine RPM.
| Identifier | ExFiles\Box 92\2\ scan0141 | |
| Date | 20th August 1931 | |
| RM.{William Robotham - Chief Engineer} P.15. COMPARISON OF LARGE & SMALL VALVES 4.78 C.R. W.W. 114" SHAFT LEG 2918 OPEN EXHAUST INS. DEFN. 3000 R.P.M. LARGE VALVES C DENOTES CLAUDEL 1.90 T TWIN CARB 1.4 DIA. CHOKE 2.55 Valve Timing Diagram: Ex (Exhaust), In (Inlet), Top Dead Centre Angles: 10, 5, Bottom Dead Centre Angles: 52, 61.8, Clearance: .013 CLCE. ① INLET VALVE THROAT 2.00 TREPANNED ROUND PORTS ② INLET VALVE THROAT 1.680 30° SEAT Hs.{Lord Ernest Hives - Chair}372 Y-AXIS LEFT: B.H.P. Y-AXIS RIGHT: B.M.E.P LBS/SQ' X-AXIS: R.P.M. Curve Labels: ①c, ②c, ①T, ②T | ||