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 various valve and carburetor configurations with a 1.1/4' camshaft.
| Identifier | ExFiles\Box 92\2\ scan0146 | |
| Date | 9th August 1931 guessed | |
| RM{William Robotham - Chief Engineer} P.24 COMPARISON OF VALVE SIZES W.W 1.1/4" CAMSHAFT 4.78 CR{Mr Cra???ster / Mr Chichester} P II UNIT OPEN EXHAUST VALVES 2" THROAT HEADMACHINED TO GIVE A MINIMUM CLEARANCE OF .2" ROUND VALVE STD 1.90 THROATS HEAD STANDARD .013 TAPPET CLEARANCE TIMING DIAGRAM: A, EX 58, IN 54, 3, 12 B TIMING. 7° EARLIER CURVE LABELS: CLAUDEL TIMING A TWIN CARBS 1.4 CHOKES TIMING B CLAUDEL TWIN DEPN TWIN CARBS DEPN CLAUDEL AXES: B.H.P. (80-170) R P M (500-3500) INDUCTION INS. Hg (1-4) B.M.E.P LBS/SQ. IN (60-120) | ||