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).
19-EX piston failures due to breaking piston stops and rapid ring wear at high speeds.
| Identifier | ExFiles\Box 15\3\ Scan060 | |
| Date | 1st July 1932 | |
| R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. E.{Mr Elliott - Chief Engineer} Du. c. Ev.{Ivan Evernden - coachwork} Hdy.{William Hardy} X7040. Hs.{Lord Ernest Hives - Chair}2/ADS.7.32 19-EX PISTON FAILURE You will see by the daily report on 19-EX that they have had a failure owing to the piston stops breaking. We have previously reported similar failures which have occurred. From our experience, these failures only occur on cars which are driven at very high speeds. We had a case on Mr. Fairey's car in which the piston ring stops had all worn completely away although there was no other damage to the pistons. We have also had it happen on the test bed when we have been doing high speed tests. Normally we never see any signs of this, therefore it is not a question of the amount of wear being increased at high speeds but it means that the tendency to wear only occurs at high speeds. E.{Mr Elliott - Chief Engineer} has looked into the question of piston rings and finds that the Phantom piston rings are relatively weaker than the 25 HP. We believe that at very high speeds a vibration starts upon the ring which causes rapid wear. Hs.{Lord Ernest Hives - Chair} | ||