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).
Laboratory report criticizing and comparing two types of oil, A and B, based on their properties.
| Identifier | WestWitteringFiles\O\2January1926-March1926\ Scan171 | |
| Date | 15th March 1926 | |
| Hs.{Lord Ernest Hives - Chair} COPY. Laboratory. H12/EA15.3.26. Report No.L383. Report and Criticism on Oils A & B submitted by you to The London Midland & Scottish Rly. Co's Laboratory. From the report issued by the above firm, A.{Mr Adams} is slightly thinner at 70°F which is an advantage, but B. has the advantage in respect of cold set. The higher free fatty acid in A.{Mr Adams} for ordinary running should be an advantage though this might be a disadvantage if the engine were left idle for protracted periods. As to the effect of heating to 200°C for 24 hrs., the amount of asphaltic bodies is not exceptionally high even in B. whereas in A.{Mr Adams} it is decidedly low. The general opinion is that much fatty oil in a compound oil is inclined to cause more carbon to form in the cyl. or thereabouts; thus compound oils are considered more essential for racing or high efficiency but straight mineral oils have the compensating advantage for the general user, in that longer periods can elapse before decarbonisation is necessary. The carbonisation test should not indicate great difference between compound oils containing 4.5 and 11.2% respectively, of the same fatty oils (other things being equal) it may be (and we have some evidence to support this) that coconut oil is more easily burnt under the conditions of test but it does not follow that it would deposit more carbon in the engine. As to spreading power or relative surface affinity, A.{Mr Adams} has the advantage, but this is in all probability largely due to its higher fatty acid content. Hl. | ||