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).
Improvements and testing for a 20 HP long duration camshaft.
| Identifier | ExFiles\Box 102\5\ scan0028 | |
| Date | 18th March 1930 | |
| CHP. From Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} x5090 Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}4/MJ.18.3.30. 20 HP. LONG DURATION CAMSHAFT. x5771 In curve V.761 you shew the 112º camshaft to give a marked improvement in performance above 1750 R.P.M. At 500 R.P.M. however, it is 5 lbs/sq.in. down in M.E.P. We want to raise the compression ratio with the 112º camshaft until we make up this M.E.P. on your test engine unit and them take a power curve. From figures we have from you comparing the 4.6 and 5.25 engines we anticipate that the required compression ratio will be 5.75. The compression pressure should also be taken and compared with standard. Having taken a normal power curve with optimum ignition advance we should like you to find how much the ignition can be retarded to drop 2% in power. The pistons RHC.{R. H. Coverley - Production Engineer} is making give - 6 - 1 No packing under cylinders. 5.75 - 1 .050 packing under cylinders. 5.5 - 1 .100 " " 5.25 - 1 .150 " " These tests should be repeated with the 116º camshaft. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||