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).
Notes on engine component design, materials, and testing, including tappets, springs, and cold chambers.
| Identifier | ExFiles\Box 147\5\ scan0137 | |
| Date | 1st July 1937 | |
| -8- Rm{William Robotham - Chief Engineer}/CTS{C. Trot Salt - Carburation}11/R.S.7.37. Bottom Tappets. The most important point is that they must turn. Selective assembly is adopted in production - tappets must fall slowly under their own weight. No trouble experienced on cars. Slight trouble on Bedford trucks after long mileage. Inspected tappets - looked like slight disintegration of cast iron. Have not harmed camshaft. As a test to improve, best material nickel chrome molybdenum iron. Inspected after prolonged running shows "polishing" effect only. This change of material has not gone any farther than one test - too expensive. Our test of cast-iron guides should improve the scheme considerably. Bottom Tappet Spring. Primary object to assist turning of tappets. Secondly, to keep tappets in continuous contact with cams for quieter running. Cam Accelerations, of Vauxhall 25 are the highest they could satisfactorily run with this scheme of bottom tappets. Critical Period of Vauxhall 25 Crank. = 3800 R.P.M. Air Silencers. 'A.C.' Type fitted. Do not affect distribution 'A.C.' men tune silencers for Vauxhall experimental requirements. Cold Chamber. When Vauxhall's first started using their cold room, it took them 3 months to get satisfactory methods of "preparing" engines for test in it, due to sudden condensation followed by freezing in electrical distributors, spark plugs, etc. We could send someone later to follow this up when we are ready to use our own cold room. Valve Springs. They appear to have carried close coiling at the bottom of the spring a stage further by having a more gradual widening of the coil spacing. Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} | ||