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).
Oil pressure failure in Bentley oil pumps, testing various solutions, and providing recommendations.
| Identifier | ExFiles\Box 149\2\ scan0135 | |
| Date | 27th January 1937 | |
| Hs.{Lord Ernest Hives - Chair} from Rm.{William Robotham - Chief Engineer} By.{R.W. Bailey - Chief Engineer} RHC.{R. H. Coverley - Production Engineer} Mx.{John H Maddocks - Chief Proving Officer} 1265 Rm{William Robotham - Chief Engineer}15/R.27.1.37. BENTLEY OIL PUMPS. As you know Hancock ran into trouble with oil pressure failure after braking on the 15,000 mile test on C.B.IV. We have reproduced this trouble in Derby. It is due to the reluctance of the helical pump to pump air. We find that on the pump we have been testing reducing the helix angle to 10° makes a big improvement. We are trying several more pumps like this to make sure that their behaviour is consistent, and that none of them is noisy. The straight tooth pump would appear to be impossibly noisy for production in this size. We also have information from Mr. Taub of Chevrolet's that we have the wrong tooth form for silent oil pumps, and we are getting a cutter to reproduce the form he recommends. The Works inform us that unless they are able to make some more oil pumps, production will be held up. We recommend that they go ahead for the next fortnight fitting 25/30 oil pumps to Bentley cars, by which time we hope to be in a position to tell them what type of large pump to make. Before cars leave for test we hope that large pumps will be available to be fitted to them. If this suggestion is not feasible then our only recommendation is to make 10° helix angle pumps. Rm.{William Robotham - Chief Engineer} | ||