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).
Analysis of radiator cooling efficiency, engine overheating issues, and a proposed redesign of the cylinder head.
| Identifier | ExFiles\Box 11\3\ 03-page217 | |
| Date | 19th July 1930 guessed | |
| -2- temperature. This proves that the radiator cooling efficiency is not sufficient when the engine is giving off its maximum heat units. Also it clearly proves and demonstrates that when the air temperature goes up to 31°C. it is again inadequate to deal with the high water temperatures from the engine. The tests also show the importance of getting rid of the air when it has passed through the radiator as quickly as possible. It will be seen from the tests that at 60 M.P.H. a considerable improvement is got when the front and rear shutters in the bonnet are open, but at 70 M.P.H. the opening of the rear shutters in the bonnet does not give any better results, but there is the same improvement by opening the front shutters in the bonnet. When looking at No. 1 test, you will observe that there is the most difference in the top and bottom water temperatures. This again proves that the engine is giving off too much heat in the top cylinder block. This is the reason why I have reported to you that I am of the opinion that there are localised heat spots in the cylinder head. You remark in your letter that tests have been taken to prove that this is not the case. From those remarks, it is obvious that the whole of the cylinder head is inadequately cooled, and in my opinion the cylinder head requires re-designing to give more water space round the valves, etc. To substantiate my opinion, I took a test with a double water supply from the bottom of the radiator to the water pump. By doing this, we maintained a higher flow of water at higher speeds, the increased loss of water verifying this. Therefore, it is not a question of increased flow in the cylinder head that is | ||