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).
The critical effect of engine water temperature on carburation and the use of a radiator blanking plate.
| Identifier | ExFiles\Box 127\5\ scan0062 | |
| Date | 11th November 1940 | |
| 109B To Ev.{Ivan Evernden - coachwork} from Rm{William Robotham - Chief Engineer}/Wym.{G. Harold Whyman - Experimental Manager} Copy to Jnr.{Charles L. Jenner} Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} Rm{William Robotham - Chief Engineer}/APS. Rm{William Robotham - Chief Engineer}/Wym.{G. Harold Whyman - Experimental Manager}2/ET.11.11.40. 8 H.P. STANDARD - PAR.649. We have found on the above car that the carburation is very critical to engine water temperature. Under standard production conditions, that is, the car as supplied to the public by the makers, the carburation is very weak in cold weather, and to get the engine to run at all reasonably, we have had to fit a 8½" deep blanking plate to the bottom of the radiator. This has the effect of raising the temperature of the water at the bottom of the cylinder block, and also slightly raising the under bonnet air temperature. Measured outlet water temperature with and without the blanking plate is 85° C., but although no actual figures of the inlet temperature have been taken, the inlet water pipe is quite cold with no blanking plate fitted, but too hot to bear one's hand on it with a blanking plate fitted. Radiator dimensions are 18½" x 13" x 1 13/16". Under bonnet air temperatures at the carburettor intake have been taken, as follows: UNDER BONNET TEMPERATURE. OUTSIDE AIR TEMPERATURE. No blanking plate fitted: 20° C. 4° C. Blanking plate fitted: 23° C. 5° C. The water system is thermo-syphon, and the induction system, whilst not being 100% water heated or exhaust heated, does receive some assistance from the exhaust manifold because it is integral with it. Rm{William Robotham - Chief Engineer}/Wym.{G. Harold Whyman - Experimental Manager} | ||