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 graph comparing BHP and BMEP against RPM for different inlet valve clearances and valve lifts.
| Identifier | WestWitteringFiles\W\September1931-November1931\ Scan033 | |
| Date | 5th October 1931 guessed | |
| R.M.47 EFFECT OF INCREASING CLEARANCE ROUND INLET VALVE JAPAN TWIN ZENITH CARBS. OPEN EXHAUST 112° CAMSHAFT E.55640 1.4" DIA. INLET VALVES TIMING TOO EARLY FOR MAX: POWER. C/R 5.35 VALVE LIFT .344 B.H.P. B.M.E.P. Inside sketch: 4.6, 2, IN, 55, .013 CLCE, Ex, 40 MAX. CLCE. ROUND INLET VALVE .225" MIN. CLCE. ROUND INLET VALVE .100 SEE SKETCH AS ABOVE BUT VALVE LIFT .395 R.P.M. | ||