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).
Engineering memorandum on the analysis of used Mobiloil 'EP' and deposits from a Bentley 3½-Litre car gearbox.
| Identifier | ExFiles\Box 173\2\ img002 | |
| Date | 29th December 1933 guessed | |
| Copy for :- Mr.Robotham c/o Vacuum Oil Co., Inc., New York ENGINEERING MEMORANDUM Bentley 3½-Litre Car Gearbox and Back Axle Lubrication. In connection with the use of Mobiloil "EP{G. Eric Platford - Chief Quality Engineer}" for gearbox and back axle lubrication on the Bentley 3½-Litre car, the two samples which were handed to Mr.O.T.Jones and Mr.J.Russell Sharp on the 20th instant have been examined very carefully in our laboratory with a view to discovering the cause of the deposits which were present in certain units after some 15,000 miles running. The sample of used Mobiloil "EP{G. Eric Platford - Chief Quality Engineer}" drawn from the gearbox is in perfectly normal condition. It contains 0.8% moisture which is due no doubt to condensation and a very small quantity of other impurities which are quite negligible. It is important to note that as far as can be ascertained, there is no indication that the compound in the oil has separated in any way, and we believe that this oil is in perfectly normal condition. The sample of deposit, also taken from the gearbox, had the following composition :- Oil 83.0% Carbonaceous material 13.4% Ash - Iron Oxide 2.8% Copper Oxide 0.4% Free Metal 0.3% Other Impurities 0.1% The metallic oxides in this are doubtless due to wear, and are not abnormal in proportion for a deposit of this nature. The carbonaceous material is stated to be "like the dried skin of boiled linseed oil, with a rubbery texture". When submitting this deposit to our laboratory, we made no mention of the fact that boiled linseed oil might possibly be present, so that this comment by our chemist is quite unbiassed. It is unfortunate that it is extremely difficult to make tests which will identify clearly the nature of this material, and actually all the deposit which we had available was used up in making the analysis quoted above. It is felt that if a further quantity of this deposit is available it may be possible to apply tests to show definitely whether it is from linseed oil or from some other source. We have also discussed the question of the action of Mobiloil "EP{G. Eric Platford - Chief Quality Engineer}" on a coating of boiled linseed oil, such as we -1- | ||