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).
Summary of performance characteristics for a high-power cylinder head, detailing power gains, detonation issues, and smoothness.
| Identifier | ExFiles\Box 134\2\ scan0061 | |
| Date | 1st July 1936 | |
| x1129 July 1936 High Power Head. Before criticising and commenting on this head, a brief summary of the position up to date would probably be of value. Power. The head has been run on the single cylinder unit and gave an exceedingly good performance, having gains over the standard head as under - 1,000 11% 2,000 7.5% 3,000 12.5% 4,000 28.0% Detonation. Detonation characteristics were rather peculiar, as there was severe high speed detonation. This was cured by fitting twin inlet valves and a salt-cooled exhaust valve, or alternatively an alum. head with twin inlet valves and a normal exhaust valve. Smoothness. Indicator diagrams showed a rather rapid rate of pressure rise using the plug in the centre of the combustion chamber, but as all attempts to alter this failed, it was inferred that it was purely local and would not necessarily cause roughness. There was an alternative plug position which, however, was found to give unsteady running. This, considering the plug position, was not unexpected, and it could probably be remedied by one of the following methods - (1) Using a long reach plug. (2) Inclining the plug to bring the points in line with the combustion chamber walls. | ||