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).
Depot sheet regarding 40/50 valve guide washers, recommending asbestos grummits to prevent fouled sparking plugs.
| Identifier | ExFiles\Box 17\6\ Scan107 | |
| Date | 13th August 1930 | |
| X.7060 To Hd.{Mr Hayward/Mr Huddy} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} (For Depot Sheet). Hs{Lord Ernest Hives - Chair}/RM{William Robotham - Chief Engineer}2/AD13.8.30. 40/50 VALVE GUIDE WASHERS. Xdeo X7970 One of the main sources of fouled sparking plugs when running under traffic conditions is oil passing down the valve guides into the cylinders when the engine is turning over slowly. This trouble usually occurs when the felt grummits which surround the valve stem become perished due to heat. Under these conditions they lose their flexibility and cease to make a seal. We have recently standardised for 40/50s grummits made in asbestos rope which have proved themselves to be much more reliable than the felt. We recommend that asbestos valve grummits should be fitted in all cases where replacement is considered necessary. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||