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).
Discrepancy between drawing specifications and test figures for engine valve timing.
| Identifier | ExFiles\Box 33\4\ Scan069 | |
| Date | 1st August 1921 | |
| Cyl - G 1821 Sheet #2. Aug.1.21 The difference between drawing and Test figures are as follows: Inlet opens Inlet closes Exhaust opens Exhaust closes after T.D.C. after B.D.C. before B.D.C. after T.D.C. DRAWING: 10º 54º 55º 10º TEST: 15.3º to 16.3º 61.2º 45º 9.2º to 15.3º The Test Dept. actually measures these points as clock minutes, taking one clock-minute equal to .800" measured around the circumference of the clutch ring which is 14.937" dia. We find .800" to be actually equal to 6.12º and have taken account of this slight difference in giving the above figures. We mentioned this matter to Mr. Pickford on his visit, but did not have an opportunity to take it up with him in detail. Yours truly, MO/g ROLLS-ROYCE OF AMERICA, Inc. Per M.{Mr Moon / Mr Moore} Olley CC Mr. Belnap Mr. Nadin Mr. Bagnall Mr. Hulley Mr. Southern Mr. Caswell | ||