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).
Engine pinking issues, referencing an experimental car and a Bentley for comparison.
| Identifier | ExFiles\Box 109\5\ scan0132 | |
| Date | 14th April 1939 | |
| 664 Sg.{Arthur F. Sidgreaves - MD} from Rm.{William Robotham - Chief Engineer} c. Hs.{Lord Ernest Hives - Chair} Rm{William Robotham - Chief Engineer}5/R.14.4.39. With reference to Sgl/E.13.4.39., we think there must be something peculiar about your car because we have run 3,000 miles on one of our experimental cars fitted with these modifications, and no pinking has occurred. Furthermore, the Bentley which has just completed 50,000 miles in France has exactly the same modifications but a slightly higher compression ratio, and you will see from Mx{John H Maddocks - Chief Proving Officer}'s report that this does not detonate excessively. We will check everything over as soon as we get the car. Rm.{William Robotham - Chief Engineer} | ||