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).
Letter from Shell-Mex and B.P. Ltd. detailing the viscosity characteristics of their standard Double Shell Motor Oil.
| Identifier | ExFiles\Box 145\3\ scan0231 | |
| Date | 10th October 1934 | |
| C O P Y Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}20/KW T & R.{Sir Henry Royce} LGC/LD. 10th October 1934. Messrs. Rolls-Royce Ltd., Derby. Dear Sirs, For the attention of Mr. Robotham. We have to thank you for your letter of October 8th, and would suggest that our standard Double Shell Motor Oil will prove a satisfactory lubricant for winter purposes. We have marketed this grade for a number of years and its distribution is, therefore, universal. It is a straight mineral oil with the following viscosity characteristics: Pour Point - 5°F Viscosity at 70°F 2,400 secs. " " 140°F 205 " " " 200°F 68 " and is, therefore, comparable with Mobiloil A.F. to which you refer. We should be very glad to supply further information if you wish it, but can assure you that our recommendation is very strong from very considerable experience of the performance of Double Shell with practically every make of car. Yours faithfully, For SHELL-MEX AND B.P. LTD., Manager - Technical & Research Dept. Received Tech. & Res. Dept. 12 OCT 1934 | ||