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).
Recommendation of Castrol oil for engines to reduce piston knocks and wear.
| Identifier | ExFiles\Box 35\2\ scan 119 | |
| Date | 9th September 1919 | |
| To EH. from R.{Sir Henry Royce} Copy to CJ. " " BN.{W.O. Bentley / Mr Barrington} X.2448 R9/G4/9/19. X.1434. X. 2778. X. 3317. RE LUBRICATING OILS AND PISTON KNOCKS. As soon as we have agreed, I propose to circulate the Sales Dept. that we recommend Castrol for the running of our engines. The extra cost of 4/4 per gallon for this oil, which apparently would run the car 5,000 miles would be .01d. per mile, which is not enough to be worth considering when one gets probably a sweeter running engine, and less wear and tear on the engine. You have reported in connection with the Buick, that this oil is less liable to get through the combustion chamber than the thin mineral oil. Exactly why this should be I cannot suggest an explanation,(except perhaps it maintains its viscosity better at high temperatures) but it would be interesting to find out which of the lubricants carbons up first, the three of interest are, Castrol, Price's motorine Band C, and Vacuum Oil of about the viscosity. R.{Sir Henry Royce} | ||