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).
New camshaft design for a 25 HP engine, comparing theoretical and practical valve timings.
| Identifier | ExFiles\Box 102\5\ scan0073 | |
| Date | 24th September 1931 | |
| Ry, from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. E.{Mr Elliott - Chief Engineer} Y5090. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}1/AD24.9.31. NEW CAMSHAFT FOR 25 H.P. [Left Diagram] 1.5 10.8 .013 clrce. 48 50.5 Inlet Duration 226.5 Exhaust " 241.5 [Right Diagram] 3.2 10.6 46.4 46.0 Inlet Duration 223 Exhaust " 236.6 It is a fact that we do not get the theoretical duration of valve opening in practice. The above timings were carefully taken with .013 clearance on two different camshafts to Sch.1153 (E.55640). The theoretical inlet valve duration is 130º but the average practical duration is only 225º and we consider that this should be taken into account when evolving the camshaft to R3/M3.9.31 for the 25 HP. Actually we think that we require the full 230º inlet valve duration recommended by R.{Sir Henry Royce} if we are to get the best results. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||