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).
Adoption of split aluminium pistons and troubleshooting an engine knock.
| Identifier | ExFiles\Box 35\2\ scan 203 | |
| Date | 26th February 1920 | |
| H.R. 235 a (100 T) (S) F 846 6.8.19 G 2469 X.2448 To Hs.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} c. to CJ. c. to Ba. c. to Da.{Bernard Day - Chassis Design} c. to Ck.{Mr Clark} RL/G26.2.20. X.2448 RE SPLIT ALUMINIUM PISTON. X.3559. X.3451. We are pleased that the pistons are shaping well. I should like to press the adoption of aluminium pistons for the repair cars. I have, however, passed the design of cast iron piston which has been sent here for re-pair work, which has been drawn upon the lines of the latest aluminium split piston. I think, however, while we are mak-ing the change, it would be better to test with a view to adopting the aluminium pistons. Regarding the illusive knock mentioned in your memo of the 20/2/20, I am inclined to think this knock may possibly be caused by the carbon accumulating just above the top ring. The only way I can suggest of avoiding it would be the location of the rings higher up, but we fear we must keep some distance between the top and the rings to prevent the heat getting to the rings. Recent memo points out that you are making exhaustive tests of piston rings in various positions and various clearances of the part above the top ring. I think this is important as there seems no uniformity of practice. R.{Sir Henry Royce} | ||