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).
Various schemes tested to resolve water circulation issues in Bentley and 20/25 engines.
| Identifier | ExFiles\Box 93\4\ scan0034 | |
| Date | 29th June 1936 | |
| -2- Hs{Lord Ernest Hives - Chair}/Std.10/KW.29.6.36. (4) Since the basic cause of the trouble could not be obviated, it was decided to endeavour to cure the trouble on the lines of the method we are standardising on the Bentley and 20/25 engines; i.e., ensuring that the water flow circulates thoroughly throughout the head. With this in view the following schemes were tried - (a) The front two water outlets into the top water rail were blanked up on each head. This reduced the temperature difference from the original 10°C. to 6°C. (b) The main outlet pipes were reduced in dia. to .750" by means of packing washers with .750" holes in them: this gave a temperature difference of 8°C. (5) As it appeared to be impossible to cure the trouble without alteration to the cylinder head, the engine was removed complete from No.50 chassis and the tests continued on the production unit test bed. Arrangements were made to read the temperatures at the rear of the cylinder head and at the outlet pipes by means of thermometers and the temperatures at various points in the cylinder head water jacket space, by means of thermo-couples inserted through holes drilled in the core plugs, the junction of the couple projecting 0.5" & 0.75" into the water space. Tests were carried out with the arrangements, and the results are shown on attached sheets ('A' series of tests). (6) The above tests being carried out on the production unit test bed, time was limited, so a more complete investigation was made on the experimental bed, arrangements tried and results obtained being shown on att. sheets ('B' series of tests). Actually, to present date, the arrangements (2) and (5) only have been tried completely, since No.(4) arrangement was only able to be tested on a different pair of cylinder heads, so that this did not give a true comparison with (2) and (5). | ||