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).
Engine oil consumption, endurance testing, and racing at Le Mans.
| Identifier | ExFiles\Box 82\4\ scan0315 | |
| Date | 4th June 1936 | |
| -3- Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}24/KWA4.6.36. (2) Oil Consumption. With regard to oil consumption, as is so often the case there is a mystery attached to this. We have run 8 or 9 endurance tests in France, where we flog the cars unmercifully, and we have never had a case (except where a bearing has failed or something of the sort) where we have not been able to average well over 1,000 miles to the gallon after 15,000 miles' running. It is however true that with the present cylinder bore finish it takes some time for the rings to settle down and get the correct oil consumption. As an example I attach the figures of our last endurance run. The official oil consumption of our experimental cars is certainly better than 800 m.p.g. There is not the slightest use of it being better than 1,500 m.p.g. because if oil stays in the crankcase too long it gets so contaminated that it helps the engine to wear out. We are following up the mystery of the 3,000 miles re-bore, as evidently there is something silly here. At the same time we have in hand a complete investigation of oil consumption which should in due course bear fruit. I shall be over at Le Mans on the Thursday. We are certainly tempting providence by letting one car run in a race of this nature against our immediate competitors, and I expect they can hardly believe our temerity. Yours sincerely, | ||