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).
Comparison of different valve timing configurations for a high power engine head, illustrated with a performance graph.
| Identifier | ExFiles\Box 111\2\ scan0284 | |
| Date | 1st 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. FIG IV HIGH POWER HEAD VALVE TIMING COMPARISONS B.M.E.P MAIN ENGINE BHP RPM TESTS CARRIED OUT ON Nº 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. | ||