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).
Recommendations on the use of S.A.E. 20 and S.A.E. 30 oils in cars, discussing consumption and starting advantages.
| Identifier | ExFiles\Box 145\3\ scan0177 | |
| Date | 12th April 1938 | |
| 1235 W/N. Br.{T. E. Bellringer - Repair Manager} from Rm.{William Robotham - Chief Engineer} c. BP. Rm{William Robotham - Chief Engineer}7/R.12.4.38. With reference to Br/M6/A.6.4.38., attached is a copy of our recommendations with regard to the new oils, and their application to cars at present being turned out of the Factory. The only thing against using thin oils on cars that were produced some little time ago is the danger of high oil consumption. If a car seems to be giving very good oil consumption with S.A.E.30, it is improbable that it will give any trouble on S.A.E.20. It should, however, be made clear to the customer that the main advantage of S.A.E. 20 is easy starting, and if he does not have any trouble on S.A.E.30, there is no particular advantage in him changing over. The only exception to this rule, we think, is in the case of a Doctor who is always running about Town, and he would certainly be better off with a lighter oil. Rm.{William Robotham - Chief Engineer} | ||