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 aluminium pistons and investigating an engine knock issue.
| Identifier | ExFiles\Box 77\3\ scan0125 | |
| Date | 20th February 1920 | |
| To HS.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} Copy to C.J. " " BN.{W.O. Bentley / Mr Barrington} " " BA. " " CK.{Mr Clark} COPY RECEIVED 4 III 1920 X3757 R1/G26/2/20. X2446 PISTON (SPLIT ALUMINIUM.) y 751 X 3559 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 repair work, which has been drawn upon the lines of the latest aluminium split piston. I think, however, while we are making the change, it would be better to test with a view of adopting the aluminium pistons. Regarding the elusive 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} | ||