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).
Performance chart showing the effect of increased valve lift on a standard camshaft and cylinder head.
| Identifier | Morton\M19\ img242 | |
| Date | 9th August 1931 guessed | |
| RM.{William Robotham - Chief Engineer} P.25 EFFECT OF INCREASED VALVE LIFT ON STANDARD CAMSHAFT AND CYL HEAD TWIN CHOKE CARB. 1.4" CHOKES OPEN EXH: 4.78 C/R.{Sir Henry Royce} STD ALUM HEAD 1.9 VALVE THROAT VALVE LIFT .430 VALVE LIFT .480 BHP B.M.E.P. LBS/D" INDUCTION DEPN INS. Hg. R.P.M. Valve Timing Diagram: 68 IN 54 EX 51 .013 CLCE | ||