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 and text comparing valve timings for a high power cylinder head.
| Identifier | ExFiles\Box 134\1\ scan0056 | |
| Date | 13th December 1937 | |
| -5- (2) I.O.TDC., I.C.35°L., E.O.35°E.{Mr Elliott - Chief Engineer}, E.C.TDC. This gave maximum low speed power at small back pressures, but seriously affected the power output relative to standard Bentley as the back pressure increased. This characteristic was much improved by using a longer exhaust duration and consequently a third timing, as under, was selected as most suitable. (3) I.O. TDC.I.C.30°L., E.O.51°E.{Mr Elliott - Chief Engineer}, E.C.TDC. Comparative power curves are shown on FIG.IV. [Graph Text] FIG IV HIGH POWER HEAD VALVE TIMING COMPARISONS B.M.E.P MAIN ENGINE B.H.P RPM TESTS CARRIED OUT ON N°5 HEAD (PHOENIX) VALVE TIMING:- ① I.O. 2°E I.C. 28°L; E.O 51°E, E.C. 7°L. ② I.O TDC I.C. 30°L, E.O 51°E, E.C. TDC. ③ I.O TDC I.C. 30°L, E.O 35°E, E.C TDC. | ||