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).
Secret memo regarding piston stops, recommending they be filed below the surface and that the practice of counterboring the stop pin hole be discontinued to avoid leakage.
| Identifier | ExFiles\Box 105\2\ scan0158 | |
| Date | 23th March 1925 | |
| X.5040 To R.{Sir Henry Royce} from E.{Mr Elliott - Chief Engineer} c. to CJ. HS.{Lord Ernest Hives - Chair} BY.{R.W. Bailey - Chief Engineer} S E C R E T. E5/M23.3.25. I N D I A.{Mr Adams} PISTON STOPS. X.5040 Further to our remarks concerning the above in E1/M23.3.25., we think the stops ought to be filed away below the surface even if in different material to avoid the risk of them coming loose. This is especially so in view of the fact that it is Derby practice to counterbore the hole for the stop pin in the depth of the ring groove, with a drill .013" to .018" larger than the pin. We should like to see this practice discontinued if possible to avoid the leakage which necessarily occurs around the pin and behind the piston ring. E.{Mr Elliott - Chief Engineer} | ||