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).
Camshaft timings, valve bounce, and cost estimations for different engine configurations.
| Identifier | ExFiles\Box 96\2\ scan0234 | |
| Date | 1st June 1937 | |
| -4- Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}5/R.1.6.37. The following timings indicate what is meant regarding the toe and main accelerations:- LeC.5401 Camshaft. Main Accelerations. At .012 clce.running timing. IO 9° PTDC IO 26° BTDC IC 35° PBDC IC 70° PBDC EO 36° BBDC EO 71° BBDC EC 4° BTDC EC 31° PTDC. Std. Camshaft Hydraulic System. Main Accelerations. Assumed Squash out of .001. IO 6° PTDC IO 18° BTDC IC 46° PBDC IC 70° PBDC EO 46° BBDC EO 70° BBDC EC 6° BTDC EC 18° PTDC. The slow running as tried on the Test Bed despite the increased overlap at running clearance is still up to standard P.III, but will be confirmed on the road. VALVE BOUNCE. Using the Bentley type of single spring with close coiled base EB.3256 the exhaust valves start to bounce at 4400-4450 RPM, whilst the lower stress springs Rs.{Sir Henry Royce's Secretary}500, which were designed for the job, bounce at 4300-4350 RPM. These are receiving the attention of E/Psn. COST. Although not done officially, our estimate of the saving in cost per engine by using the solid rocker gear would be £14. This is taking into consideration the overhead charge on labour of 175%. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} | ||