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).
Blueprint comparing four different desirable camshaft timing diagrams for the 40/50 model.
| Identifier | Morton\M19\ img205 | |
| Date | 18th June 1931 guessed | |
| DESIRABLE CAMSHAFTS FOR THE 40/50 1. S. 381 o 11 EX 240 INLET230 49 112° 25 H.P 2. 5.5° 7.6° EX 241 IN226 52 53.5 116° 40/50 LIFT .420 3. 2° 10° EX 240 IN240 58 50 BEST TIMING OBTAINABLE USING 40/50 EX. CAMS. 114° CAMS 4. o 8° EX 236 IN236 56 48 ASSUMING THAT WE ARE UNABLE TO OPEN THE INLET VALVE MUCH BEFORE T.O.C. ON ACCOUNT OF ROARING, WE CONSIDER 3 WOULD BE THE BEST TIMING WE CAN GET WITH EXISTING CAM FORMS WHILST 4 MIGHT BE PREFERABLE WITH NEW CAM FORMS. CAMSHAFT 1 WE KNOW GIVES GOOD RESULTS. | ||