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 comparing engine performance based on different valve sizes and camshaft timings.
| Identifier | ExFiles\Box 182\M19\ img241 | |
| Date | 5th August 1931 guessed | |
| RM.{William Robotham - Chief Engineer} P. 24 COMPARISON OF VALVE SIZES W.W. 114 CAMSHAFT 4.78 C.R. P II UNIT OPEN EXHAUST VALVES 2" THROAT HEAD MACHINED TO GIVE A MINIMUM CLEARANCE OF .2" ROUND VALVE STD. 1.90" THROATS HEAD STANDARD .013 TAPPET CLEARANCE TIMING DIAGRAM: EX 58, IN 54, TDC markers 3, 12 TIMING A B. TIMING 7° EARLIER CLAUDEL TIMING A TWIN CARBS 1.4 CHOKES TIMING B CLAUDEL TWIN DEPN TWIN CARBS DEPN CLAUDEL B.H.P. INDUCTION DEPN INS. HG. B.M.E.P. LBS/SQ IN. R.P.M. | ||