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).
Brief report on the development of a high-power engine head, detailing issues and recommendations.
| Identifier | ExFiles\Box 134\2\ scan0132 | |
| Date | 23th August 1937 | |
| HIGH POWER HEAD. The following is a brief report of all the work done on the above head since the start of its development. Salient points are given, and recommendations for a main engine made. (1) CYLINDER DISTORTION & RING GUMMING. A 50 hour endurance on the original engine caused piston rings to gum up badly on the exhaust side, with resultant blow-by causing picking up of the piston. This was cured by placing a water jet, as shown in Fig.l, and blanking off the water inlet at the bottom of the cylinder to .125" dia, thus pushing most of the circulating water through the jet. A 100 hours endurance was then run satisfactorily. The following points arise:- (a) The distance between the exhaust ports and the cylinder walls must be kept reasonably large to permit a decent water space. (b) The main flow of circulating water should be injected between the port and the cylinder with a small feed only at the base. In a main engine it may be necessary (i) to feed water to both ends of the block to a long water rail. (ii) to feed the water to the centre of the rail. (c) Siamised exhaust ports may become too hot, and allowances in the design for a six port system should be made. (2) HIGH SPEED DETONATION. A peculiar form of "detonation" was evident on these heads at high speeds. It is considered that this is a form of pre-ignition, and the main controlling factor appears to be the throat area. In order of importance, high speed detonation was influenced by:- (i) throat area. (ii) exhaust valve temperature, i.e., solid or cooled valves. (iii) type of gasket:- C. & A.{Mr Adams} corrujoint or aluminium. (iv) plug position. | ||