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 comparing engine performance based on different valve lift specifications and timing.
| Identifier | ExFiles\Box 92\2\ scan0142 | |
| Date | 9th August 1931 | |
| COMPARISON OF VALVE LIFT 114° SHAFT R.M. P.19 LARGE VALVE HEAD. 4.78 C/R 2.0" VALVE THROAT 114° CAMSHAFT E.82448 OPEN EXHAUST TIMING .013 C.L.C.E. I.O. 3° B.T.C E.O. 54° B.B.C I.C. 58.1 P.B.C. E.C. 12° P.T.C. HIGH LIFT TIMING .013 C.L.C.E. I.O. 2.25 B.T.C E.O. 54 B.B.C I.C. 60.3 P.T.C. E.C. 19 P.T.C VALVE LIFT .525 VALVE LIFT .470 TWIN CARBS 1.4" THROATS CLAUDEL HIGH & LOW LIFT HEAD MACHINED TO GIVE A MINIMUM OF .2 CLEARANCE ROUND THE INLET VALVE HEAD SIMILAR CURVES TAKEN WITH CLAUDEL CARB. SHEWED NO INCREASE IN TOP M.E.P. BUT A SLIGHT DROP IN LOW SPEED M.E.P. / 2 LBS / O" WITH HIGH LIFT ROCKERS Y-Axis Left: B.H.P X-Axis: R.P.M. Y-Axis Right: INDUCTION PIPE DEPN "H2O", B.M.E.P. LBS/O" | ||