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).
Piston rattle faults, decarbonisation, and recommendations against immediate modifications to engines.
| Identifier | ExFiles\Box 35\2\ scan 212 | |
| Date | 31th January 1930 | |
| To R.{Sir Henry Royce} from En. To CJ. - 3 - Bnl/W22320 Contd. rattles developed) whereas before the War we were forced to recommend decarbonisation of pistons and cylinders after 3000 miles owing to the development of detonations. It appears from this that we are considerably in advance of the pre-war car as regards distance which can be run before decarbonisation is necessary. From careful consideration of all available information it is recommended that no action be taken to change or modify pistons of chassis which have been delivered, chassis which are on test, and engines erected or erecting in the Shops. At this stage also it is not recommended that any modification be incorporated in pistons in course of manufacture. It is considered that the piston rattles experienced form a fault which must be urgently and fully investigated, but from the information at present available it is not certain that it will appear in standard cars when standard oil is used. It is possible by fitting a top ring practically to ensure that this fault will not occur but the tests and experiments have not proceeded far enough to satisfy us that no new fault or other difficulty will arise through the incorporation of this proposed modification. The altered parts have run 10,000 miles or their equivalent and the incorporation of any new part without such test is only recommended when a definite fault of a serious nature has been discovered. At the moment we have no evidence of a definite nature that the fault will occur on standard cars. It is therefore recommended that the matter be raised again in 10 days time for further consideration in order that it may be decided whether (Contd.) [Stamped Text: RECEIVED CHIEF ENGINEER'S OFFICE 31 JAN 1930] | ||