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 showing actual valve timing data from twin carburetor tests on a 'Japan' engine with .020 tappet clearance.
| Identifier | ExFiles\Box 56\2\ Scan168 | |
| Date | 21th May 1930 guessed | |
| ACTUAL VALVE TIMING TAKEN ON ENGINE WITH .020 TAPPET CLCE. | CAMSHAFT. | 116° | 112° | 110° | |------------|--------------|--------------|--------------| | In. OPENS. | 13° A.T.C. | 7° A.T.C. | 16° A.T.C. | | In CLOSES. | 48° A.B.C. | 43° A.B.C. | 37° A.B.C. | | Ex. OPENS. | 42° B.B.C. | 43° B.B.C. | 28 B.B.C. | | Ex. CLOSES.| 2° A.T.C. | 5° A.T.C. | 4° A.T.C. | ABOVE ARE THE BEST TIMINGS FOUND DURING TWIN CARB TESTS ON 'JAPAN'. aclt. | ||