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).
Experiment with a Bentley 'S' direct-acting exhaust valve system compared to a normal rocker ratio system.
| Identifier | ExFiles\Box 158\4\ scan0230 | |
| Date | 10th March 1938 | |
| -3- Rm{William Robotham - Chief Engineer}/Swd1.1/JR.{Mr James Royce}10.3.38. 28.3.IV. has been fitted with the conditions of the second experiment. For Bentley 'S' where the exhaust valve is working direct from the cam, the lift and corresponding loading on the cam and tappet will be higher than the normal system where a rocker ratio is used. This is why the fourth experiment was tried PD.123 where other than being backed off at the cam tips the cam width is full at the high accelerations. Other than an additional machining operation on the cam this seems quite satisfactory to use and we can later prove whether it is essential to use this rather than a reduced cam width where no backing off is required. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} | ||