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).
60-hour test bench results for split silent pistons.
| Identifier | ExFiles\Box 77\3\ scan0011 | |
| Date | 11th November 1919 | |
| R.R. 235A (500 T) (S.D. 408. 26-4-17.) Bm. 2/156/13. To R.{Sir Henry Royce} from EH. Copy to CJ. " " BN.{W.O. Bentley / Mr Barrington} " " E.{Mr Elliott - Chief Engineer} " " DA.{Bernard Day - Chassis Design} " " EP.{G. Eric Platford - Chief Quality Engineer} EH8/LG4.11.19. 9/32 RE SILENT PISTONS. X.3651. We have run a set of split pistons for 60 hours on the Test Bench. The speed has averaged from 2000 to 1200 R.P.M. full throttle the whole time. We examined the pistons after 60 hours running and found them to be in very good condition. We measured them with a micrometer and the maximum amount of wear we could measure was .0005", in fact there was not sufficient for us to be certain that any wear had taken place at all. These pistons are running on the fitting portion i.e. .003" to .002"; they were ground oval; the grinding being carried well round. In starting the engine up dead-cold after we had examined it we could not pick out any knocks at all. After we have completed the 100 hours we shall fit these cylinders and pistons on to a car and see what they are like on the road. A full report on the 100 hour test will be sent to you when the test is completed. We are using on this engine castrol oil. Mr. Platford has also got two cars running continuously fitted with split type pistons. One is running usefully between London and Derby and the other is either on the dynamometer or used on the road. So far we have not discovered any "nigger" with the split pistons. The patterns for the newplunger pistons will be Contd. | ||