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).
The use of mineral oil in cars, addressing issues of acidity and 'squawks' in 20 HP models.
| Identifier | ExFiles\Box 144\1\ scan0110 | |
| Date | 1st January 1925 | |
| HS.{Lord Ernest Hives - Chair} /967 BY6/H.{Arthur M. Hanbury - Head Complaints} 1. 1. 25. MINERAL OIL ON CARS. Referring to Hs{Lord Ernest Hives - Chair}6/LG. 30.12.24. we are at the moment actually trying out a mineral oil supplied by Prices. I am having same carefully checked against Vacuum BB. and if it appears to be reasonably the same in general characteristics, I propose to try this for "running in" and testing in the Works. In regard to the peculiar fact that the 20 HP. seems to be particularly liable to squawks, I am inclined to think that the same thing will be found true of the EAC.II, and that it is possibly due to the fact that the engine being somewhat higher in compression will work on a leaner mixture, and the oxidising effect of the excess of air in the charge will be to increase the acidity of the oil considerably. There is one point worth making clear, namely, that when I was speaking of the acidity of the oil, I did not refer to its original acidity, but its tendency to turn acid under running conditions in the cylinder barrel, which in my opinion is enhanced by the use of lean mixtures, so that it is quite probable that the customer who has the trouble may be a customer who is always trying to run on the leanest possible mixture, which would possibly account for the fact that we only have trouble with a certain number of our 20 HP. customers, not a high percentage, but still, when we do have trouble with them, it seems to persist, and of course the customer never leaves us alone so long as he has trouble. In these special cases I have recommended EP.{G. Eric Platford - Chief Quality Engineer} for the present to recommend the use of Vacuum BB. If we find by our tests and use in the Test Dept. that Prices' mineral oil is equally good, we shall recommend Prices, of course. The point I had in mind was not so much changing from Prices' to Valvoline or Vacuum BB. as to have an alternative recommendation. Contd. | ||