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).
List of recommendations for improving a mechanical system, focusing on plunger valves, eccentrics, and rocker shafts.
| Identifier | ExFiles\Box 106\5\ scan0083 | |
| Date | 7th March 1933 | |
| -3- The following recommendations are made which would improve the working of the system :- (1) The plunger valves and seatings should have the best possible machine finish - preferably ground - lapping is not satisfactory owing to the absence of any guide for the purpose. The seating should be kept thin, and it might be an advantage to substitute a spherical seating about .005" - .010" deep for the present one (using same valve). (Attention has already been drawn in a previous report of Matthews' to the necessity for a good finish on valves). (2) The present combination of bearing metals for the eccentrics should be altered - cast iron or preferably one of the high tensile ferrous alloys being substituted for the nickel of which the eccentrics are at present made. As a quick test we should like to try a shaft in Nitro Alloy with the existing rockers whilst waiting for those in C.I. (3) The eccentric clearance on the rocker shaft should be reduced - this could be done if a more suitable bearing material is used for the eccentrics - at present some of the eccentrics show signs of 'pitching' on the shaft under the combined valve and eccentric arm loads - this is the main cause of the trouble with No. 2 eccentric. (4) Limits arranged to prevent eccentric oil hole trouble. Further attempts at easing No. 2 eccentric and shaft have shewn no improvement - apparently the slight pitching of the eccentric with consequent heavy loading near one end results in continual 'picking up'. A power curve taken from the engine with tappets in their present state is attached. Hs{Lord Ernest Hives - Chair}/C. S. Steadman. | ||