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 with different valve sizes, carburettors, and timings on a W.W. 114° camshaft.
| Identifier | Morton\M19\ img241 | |
| Date | 9th 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 B TIMING. 7° EARLIER Valve Timing Diagram labels: A, Ex, IN, 3, 12, 58, 54 CLAUDEL TIMING A TWIN CARBS 1.4 CHOKES TIMING B CLAUDEL TWIN DEPN TWIN CARBS DEPN CLAUDEL B.H.P. R.P.M. B.M.E.P. LBS/SQ. IN INDUCTION DEPN. INS. Hg | ||