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).
Modification to the Wraith cylinder head thermometer bulb position to prevent erratic ignition.
| Identifier | ExFiles\Box 175\5\ img026 | |
| Date | 16th March 1938 | |
| To HPS.{Horace Percy Smith - Experimental Factory Mgr} from Rm{William Robotham - Chief Engineer}/Std. c. Rm{William Robotham - Chief Engineer}/Wym.{G. Harold Whyman - Experimental Manager} 6003 Rm{William Robotham - Chief Engineer}/Std.1/AP.16.3.38 WRAITH CYLINDER HEAD THERMOMETER BULB POSITION As a result of the fitting of the R.R. distributor in Wraith and also the raising of the distributor mounting face, the thermometer capillary with the bulb in the new front position passes too close to the distributor leads, and may result in erratic ignition operation. To avoid this it is necessary to move the bulb position to another point and the only feasible one is that shown on SCD.504. We wish to test this out immediately before it is detailed and instructed for production. Will you please modify a Wraith cylinder head (which we will hand you) to this drawing so that a test can be made on the test bed. Will you also please cancel our instruction for SCD.777 modification on all existing heads and substitute SCD.504 for it. Rm{William Robotham - Chief Engineer}/Std. | ||