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).
Diagnosing and curing an elusive squeak or note in the engine, caused by the oil pump gears.
| Identifier | ExFiles\Box 66a\2\ scan0238 | |
| Date | 30th October 1928 | |
| To Hs.{Lord Ernest Hives - Chair} from Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux} 48060 HS{Lord Ernest Hives - Chair}/GWH{George W. Hancock - Head Chateauroux}1/LG30.10.28. RE. DEPOT SHEET NO. HM.{Capt. W. Hallam - Head Repairs} 87. 4/4/T X8150 We have had cases of an elusive squeak or note on an experimental chassis and chassis on test. We believe this also has occurred on customers cars. The noise starts low and builds up very similar to an electric horn (not Klaxon). It comes on when the engine temperature is normal. The squeak or note is very elusive and difficult to locate. It invariably comes on after pulling up in traffic or turning sharply right or left. It may appear to come from front brakes, engine gears, dynamo or magneto. It cannot be produced with the car standing still and the car may be driven all one day without producing it. The cause is the oil pump gears setting up a vibration when the load is temporarily taken off, due to air getting in the system when suddenly braking or cornering. The noise comes from the main feed oil pipe to the relief valve, or the valves in the relief valve unit. We find that it can be cured by changing the oil in some instances. When this does not effect a cure, the oil pump must be changed. The oil pump causing this trouble had gear wheels with the teeth unevenly cut and cross-binding. Hs{Lord Ernest Hives - Chair}/G.W.Hancock. | ||