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).
Summary of tests on improving volumetric efficiency by fitting two inlet valves per cylinder instead of a single valve.
| Identifier | ExFiles\Box 17\6\ Scan159 | |
| Date | 25th September 1933 | |
| -3- Hs{Lord Ernest Hives - Chair}/Std.S/KT. 25.9.33. valves/cylinder" head with a "single inlet valve/cylinder" head with other conditions equal, but these tests indicate that the superiority of the 6 litre Bentley head must be due to the short port design, and in main the two inlet valves/cyl. design. SUMMARY. These tests show that the most important point for improving the volumetric efficiency of the existing design of R.R. cylinder head, is to fit two inlet valves per cylinder. Apart from improving the orifice coefficient, we can get about a 20% increase of valve area per litre, by using double instead of single inlet valves. The other feature which may be expected to give some return, is shortening the induction port. Hs{Lord Ernest Hives - Chair}/C.S.Steadman. See X1497 for prints | ||