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).
Report page detailing the performance and maintenance requirements of various engine valves and bearings under test conditions.
| Identifier | ExFiles\Box 140\1\ scan0226 | |
| Date | 2nd September 1938 guessed | |
| -22- The chome-nickel steel intake valves supplied as standard equipment in the engine were used throughout the test without replacement. It was necessary to grind these valves after approx. 100 hours of operation, regardless of conditions of engine operation. The exhaust valves used during the test were selected as engine conditions dictated. With an intake manifold pressure of 10 inches of mercury above atmospheric, Silichrome No.1 valves were definitely unsatisfactory for engine speed above 2,000 rpm. at full throttle. From the point of view of commerical application, these valves would probably be unsatisfactory at this manifold pressure and even lower engine speeds, since it was necessary to grind them after approximately each 20 hours of operations at the relatively lowengine speeds, since it was necessary to grind them after approx. each 20 hours of operation at the relatively low engine speed of 1000 rp.m Exhaust valves of S.A.E. number 2112 steel were substituted for the silichrome No.1 valves. These showed a slight improvement but there is still a question of their giving satisfactory service in a supercharged passenger car or commercial vehicle operated continuously at a high load factor. Although these vales could be used up to speeds of 4000 r.p.m. it was necessary to grind them after approximately each 20 hours of operation. The best results were obtained with Stellite-faced valves although even they were not entirely satisfactory. However, dynamometer service of this sort is known to produce much shorter exhaust valve life than the most severe road operation. so the exhaust valve problem may not be as serious as it might at first seem. Babbitted connecting rod bearings proved to be quite satisfactory for supercharged engine operation. The main and camshaft bearings supplied with the engine were quite satisfactory. In general, very few mechanical problems were encountered and none of them appeared to be insurmountable for the engine designer. Acknowledgment. The author is much indented to Mr. Charles D.{John DeLooze - Company Secretary} Hawley and Mr. Earl Bartholomew for their criticisms and editorial assistance in the preparation of this paper. | ||