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).
Translated article discussing the causes of oil degradation and the requirements for effective oil filters.
| Identifier | ExFiles\Box 135\3\ scan0233 | |
| Date | 16th February 1938 | |
| Translation from "L'Auto" 16/2/38. Redex 1139 Towards less frequent oil changes [Handwritten note] SWB we should try & get hold of one of these filters for comparative purposes The introduction touches upon the changes in the chemical and physical properties which unfavourably influence the character of lubricating oils. It appears to be a matter for reflection that, after mechanical construction has progressed so far as to give engines with moderate oil consumption, the oil has to be drained every 3,000 km. Mentioning crankcase capacity and the expenditure incurred for a 25,000 km. annual mileage, it goes on to deplore the apparent lack of means for suppressing this too frequent drainage and ends up by stating that such a means has just been discovered. Professor J.{Mr Johnson W.M.} Clower of the Polytechnic Institute of Virginia first determined the source and nature of these impurities. The following are 'inherent':- Bodies formed chemically during the course of use. Those which exist in the oil in its crude state and which cannot be eliminated by the refining process. Those which are introduced during the refining process and which cannot be got rid of. On the other hand there are exterior impurities which get into the oil during storage and under working conditions. The crude oil contains a deal of harmful ingredients such as sulphur and unstable hydrocarbons. During refinement the oil comes into contact with various solvents, acids, water and air. Sources of 'non-inherent' impurities are given, followed by the requirements which a good filter should fulfil: a) Remove all harmful impurities. b) Easy mounting c) Initial and upkeep cost which gives real economy. d) Absolute safety of working e) Capable of good service for 10,000 or more km. f) No oil leaks or short-circuits g) Capable of collecting all water and other impurities. | ||