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).
Test results for 40/50 camshafts, focusing on timing adjustments and large diameter inlet valves.
| Identifier | ExFiles\Box 182\M19\ img201 | |
| Date | 17th June 1931 | |
| ORIGINAL To E.{Mr Elliott - Chief Engineer} From Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}8/KT.17.6.31. 87090 40/50. CAMSHAFTS. We have been trying to obtain some more information for you. TIMING Lec.2918. The first thing we did was to try and reproduce the timing given on Lec.2918. again and compare it with the best we have done with the R.{Sir Henry Royce} engine shafts. Sheet Hs.{Lord Ernest Hives - Chair}379 shews the result. The curve given for "A" timing cancels the previous curves given in Sheet 3. of our last note as we found a defect in the brake which caused inaccuracy. "A" timing is the same as Lec.2918 except that we open the inlet valve 14 degrees earlier. The two curves on Hs.{Lord Ernest Hives - Chair}379. shew that we lose a considerable amount of low speed torque with the proposed timing and at the same time are actually also down at the high speeds. LARGE DIA. INLET VALVES. Hs.{Lord Ernest Hives - Chair}380 shews a repeat test on the large and small valves with a different camshaft; the difference between the two is reduced but the same characteristic remains. i.e. the large valves are inferior over the whole useful range. The valves were fitted to different heads so that we still have to check the c/r.{Sir Henry Royce} accurately to ensure there is no difference. We shall shortly be able to report on - (1) Std. Inlets 30º seats. (2) Inlets the size of existing exhaust. (3) Std. Inlets with head machined to give greater clearance. (4) As (3) but larger inlets. This should clear up some of the existing mysteries. REAR WITH EARLY INLET OPENING. Have been looking up some of the tests we did on this with the R.A.E. indicator Hs.{Lord Ernest Hives - Chair}3/LG20.9.23. The conclusions said - | ||