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).
Diagnosing and rectifying engine detonation issues in a 'New Wraith' car by adjusting ignition and fuel.
| Identifier | ExFiles\Box 109\5\ scan0142 | |
| Date | 21th July 1939 | |
| 664 COPY FOR FILES. Rm{William Robotham - Chief Engineer}/FD.{Frank Dodd - Bodies}9/JH.21.7.39. Sg{Arthur F. Sidgreaves - MD}'s. New Wraith. When this car arrived it was running on Discol petrol, car was tested but there were no detonations. The ignition was checked, Kennett having reported altering the distributor points, the ignition was found to be 1/2" late. We removed the Discol and put in Shell No.1 re set the ignition to T.D.C. and tested car. The detonations were apparent immediately, and persisted throughout the entire speed range being very noticeable between 50 - 60 m.p.h. The automatic advance was checked on the rig and found to be correct for the standard Wraith. It was decided to alter the curve characteristic to the Bentley V, this was done and the car again tested on Shell No.1. Detonations are now passable at low speeds and have entirely disappeared up the range. If cars are expected to run on Shell No.1 with the raised crown pistons and Bentley camshaft it will be necessary to have the distributor altered to the Bentley V type of governor to avoid complaints of detonation, It was noticed that the engine was not quite so lively with this governor, and there is no question that for performance more advance and a higher Octain petrol are to be preferred. The car was handed over to LA.{L. A. Archer} for further modifications, i.e. change cyl. block, fit roll rod etc. Rm{William Robotham - Chief Engineer}/RD. | ||