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 comparison graph of high and low lift rockers with different valve timings and configurations.
| Identifier | ExFiles\Box 102\5\ scan0093 | |
| Date | 5th October 1931 guessed | |
| R.M.44 COMPARISON OF HIGH & LOW LIFT ROCKERS, WITH TWIN ZENITH CARBS. JAPAN UNIT. INLET VALVE DIA 1.4. OPEN EXHAUST 112º. CAMSHAFT F.55640. A.{Mr Adams} LIFT .395 LIFT .344 COMP. RATIO 5.35/1 TIMING TOO EARLY FOR MAX POWER. VALVES SHROUDED BY CYL. HEAD. Ex. 40 IN 55 4.6 2 .013 CLCE B. LIFT .395 LIFT .344 COMP RATIO 5.15/1 TIMING TOO EARLY FOR MAX POWER. MIN CLCE OF .225 CUT ROUND INLET VALVE. Ex. 40 IN 55 4.6 2 .013 CLCE C. LIFT .395 LIFT .344 COMP RATIO 5.15/1 TIMING CORRECT FOR MAX POWER. MIN CLCE OF .225 ROUND INLET VALVE. Ex. 46 IN 46 3.2 10.6 .013 CLCE B.H.P. M.E.P. R.P.M. | ||