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).
The effect of exhaust valve lift on engine performance, including a comparative power graph.
| Identifier | ExFiles\Box 111\2\ scan0285 | |
| Date | 13th December 1937 | |
| -6- Rm{William Robotham - Chief Engineer}/Ed.{J. L. Edwards}9/AP.13.12.37 V.{VIENNA} EXHAUST VALVE LIFT The Design Department stated that if rotating bottom tappets were to be used, the maximum exhaust valve lift would be about .312". A rough test was accordingly run by increasing the tappet clearance and lengthening the exhaust valve duration until the same timing was obtained as before. The minimum lift which could be obtained was .338" and comparative power figures are shown in Fig.V. where a very serious falling off in power is shown. [Graph Text] HIGH POWER HEAD FIG V EFFECT OF EXHAUST VALVE LIFT EXHAUST VALVE LIFT .380" EXHAUST VALVE LIFT .338" Y-Axis Left: B.M.E.P. Y-Axis Right: MAIN ENGINE B.H.P X-Axis: — R.P.M. — TESTS CARRIED OUT ON N°4 HEAD WITH I/C BLOCK AND 1.600" DIA. EXHAUST VALVE VALVE TIMING: I.O. TDC; I.C. 30°L; E.O. 51°E; E.C. 7°L. | ||