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).
The failure of 'V' series pistons due to ten broken rings.
| Identifier | Morton\M3.1\ img006 | |
| Date | 1st April 1925 | |
| R.R. 493A (50H) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. BJ. c. to RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} c. to DA.{Bernard Day - Chassis Design} EY. c. to Wox. Expl. No. REF: Hs{Lord Ernest Hives - Chair}/LC/1.4.25. SECRET EAC. 'V' SERIES - PISTONS. X8040 Further tests with the pistons in which two rings were fitted in the one groove, the top one being weaker than the lower one, confirm that there was no appreciable reduction in the oil consumption. When we dismantled these pistons we found ten broken rings. The failures occurred on the top and second pair of rings. 6 of the rings were the strong type and 4 of the rings the weak type. These pistons have now been removed from the engine and we are fitting a set of pistons with 4 plain rings and one wide scraper ring as instructed by R.{Sir Henry Royce} when he was last at Derby. Hs.{Lord Ernest Hives - Chair} | ||