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).
Experiments to lower exhaust valve temperatures on a cylinder head.
| Identifier | ExFiles\Box 106\5\ scan0178 | |
| Date | 11th December 1936 | |
| 354 554 To E.{Mr Elliott - Chief Engineer} from Rm{William Robotham - Chief Engineer}/Mths.{Reg Matthews} c. to Hs.{Lord Ernest Hives - Chair} c. to By.{R.W. Bailey - Chief Engineer} c. to E/TGD. Rm{William Robotham - Chief Engineer}/Mths.{Reg Matthews}18/AP.11.12.36. EXHAUST VALVE TEMPERATURES. Further to our report Rm{William Robotham - Chief Engineer}/Mths.{Reg Matthews}35/AP.12.11.36., we have continued our experiments on valve temperatures on the LeC.5222 head and the standard 25/30. cylinder head. We have not succeeded in lowering the valve temperature of the LeC.5222 head below that of the standard head, in the later experiments the valve temperature of the standard head was a maximum of 842°C., this temperature is slightly higher than the previous figure of 834°C. for the standard head, but this slight difference may be accounted for in two ways. First, at the same time that we modified the LeC.5222 to take the larger valves, we also changed the camshaft, and secondly, the optical pyrometer used in these tests had, during the time we were not using it, been re-calibrated once or twice. The modification of the LeC.5222 head by increasing the size of the exhaust valves from 1.225 to 1.400 resulted in a decrease in temperature from 870°C. to 850°C, and even then the temperature was still 8°C. higher than the standard head. By increasing the diameter of the valves on the standard cylinder head from 1.225 to 1.400 we only managed to decrease the valve temperature by 6°C. from 842° to 836°C., but in this case increasing the size of the port at the valve seat portion does not have as marked effect as increasing the ports of the LeC.5222 head which as pointed out in our previous report, is restricted more than the standard head by lowering the water jacket round the valve guides. Rm{William Robotham - Chief Engineer}/Mths.{Reg Matthews} | ||