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 rattles caused by carbon build-up and a proposal for a new six-ring piston design.
| Identifier | ExFiles\Box 35\2\ scan 229 | |
| Date | 20th April 1920 | |
| R.H. 250 . 100 T/PxF. 846. 6-8-19. O.{Mr Oldham} 2460. X.2448 To Hs.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} Copy to CJ. " " Bn.{W.O. Bentley / Mr Barrington} " " Da.{Bernard Day - Chassis Design} " " EFC. " " By.{R.W. Bailey - Chief Engineer} R14/G20.4.20. X.2748. RE PISTON RATTLES. X.3751a. With reference to piston rattles, and the accumulation of carbon above the rings causing tightness, I should be glad if you would examine whether the same fault occurs with the cast iron under the same lubricating conditions as has been found in the aluminium pistons. Secondly, I agree that we press forward standardisation sheet for the six-ring type, but taking care not to make the top band of metal too narrow, in such a way that if the carbon did deposit there it could be very easily pulled off. One would therefore suggest that the top edge was rounded or bevelled and the top ring a little further from the top of the piston. [Handwritten diagram of a piston head profile with the word 'Thus'] R.{Sir Henry Royce} | ||