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 showing the effect of increasing clearance around the inlet valve on engine performance with twin Zenith carburettors.
| Identifier | ExFiles\Box 102\5\ scan0096 | |
| 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 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. Ex .013 CLCE IN 40 55 46 2 MIN CLCE ROUND INLET VALVE .225" MIN CLCE ROUND INLET VALVE .100 SEE SKETCH AS ABOVE BUT VALVE LIFT .395 R.P.M. | ||