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).
Optimum camshaft timing and performance results from engine tests.
| Identifier | ExFiles\Box 1\10\ B001_X106 TO X 110-page039 | |
| Date | 12th July 1932 | |
| -2- Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}7/MA.12.7.32.Cont'd.{John DeLooze - Company Secretary} The optimum camshaft from these tests would appear to be the following timing :- [Diagram showing camshaft timing with values: EX 34, IN 34, 2, 6] The best low speed power results would be obtained with the minimum length of toe for silence between .003"& .013"valve lift, and the quickest lift practical between .013"& .020" With this camshaft, small valves long reach plugs, an effective hot spot and 6/1 C.R. we should get 105 M.E.P. at 1000 R.P.M. which we think will be reasonable and we should top 70 B.H.P at 75 M.P.H. which is a fair compromise. In studying these curves it should be noted that the single S.U. is not ideal with our 6 part pipe for distribution below 2000 R.P.M. and we are fixing up a better system. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||