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).
Letter from F.H.R. to Claude Johnson regarding a big end bearing failure on an experimental car and suggestions for testing oil pressure.
| Identifier | ExFiles\Box 16\1\ Scan048 | |
| Date | 15th June 1912 | |
| T.C. On Warwald COPY. Beacon Hotel, Hindhead, Surrey 15th June 1912. Mr Claude Johnson from F.H.R. With reference to attached re experimental car (1849) from France. I am sorry to hear of the failure of the big end bearing. I do not think that it indicates conclusively the necessity of extra pipes to the intermediate bearing. This engine had rather high compression, and the intermediate crank would always be the one to fail if the oil failed intermittently. I have suggested/that the pipes and passages to the three main bearings be increased. This also would include a good annulus in the bearing. I think this would be a good opportunity for making this test, but at the same time the dynamometer or test plate tests should be quite capable of demonstrating whether this increase in the passages/is sufficient for the highest speed running at the greatest power. The pump, of course, must have sufficient capacity to maintain the pressure, and experiments may be made with different pump pressures to find the maximum pressure that can be maintained with the pump when the oil is hot, and the minimum pressure that the engine will run with without failure. It is worth while reducing the oil pressure slightly until the engine gives out to determine whether with this increase of passages what pressure of oil is necessary. Comparing this with standard engine with present pipes and passages will let us X740 | ||