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 182\M19\ img238 | |
| Date | 5th August 1931 | |
| COMPARISON OF VALVE LIFT 114° SHAFT R.M. P.19 LARGE VALVE HEAD + 7/8 DIA 2.0" VALVE THROAT 114° CAMSHAFT EX2448 DOWN CAMSHAFT TIMING ON C.L. 5.8" ----- POINT CAMS ---- I.O. 3° B.T.C I.C. 31° A.B.C E.O. 39° B.B.C E.C. 3° A.T.C HIGH LIFT TIMING - DRG. 4141 I.O. 12°.25' B.T.C I.C. 37° 15' A.B.C E.O. 38°.25' B.B.C E.C. 11° 15' A.T.C VALVE LIFT .525" VALVE LIFT .570" B.M.E.P. R.P.M. INDUCTION PIPE DEPN (LBS/SQ") B.M.E.P. (LBS/SQ") GEARED FAN 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/SQ" INDUCTION DEPN ROSE .35" HIGHER WITH HIGH LIFT ROCKERS | ||