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).
Overcoming piston knocks, considering split pistons and the potential use of cast iron over aluminium due to production issues.
| Identifier | ExFiles\Box 77\3\ scan0050 | |
| Date | 12th December 1919 | |
| R R.{Sir Henry Royce} 235 a (100 T) (S.F 846 6 8-19) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2460 Contd. -2- Hs{Lord Ernest Hives - Chair}3/LG12.12.19. best thing we know of to overcome piston knocks, we think that the design of those pistons, as split pistons, should be the best we can do. The outstanding virtue of the split pistons is the fact that it is impossible to seize them up on the fitting portion. We are getting, on some of the cars, a slight knock when the engine is hot and just turning over slightly. This knock occurs with either the split type as solid trunk type piston. The characteristic of the knock is not like a piston knock; it is very elusive and difficult to trace! We are investigating the cause of it. We feel very anxious about the pistons positions because there is no doubt that we shall bever satisfy the Sales Dept. until we supply them with an engine which under no condition can they find a knock. At present the Works are producing a very few pistons because of the Moulders Strkde, but as soon as the Strike is over, the Works will have a start on a very large batch of pistons. There are a great number of cars nowsimply waiting for pistons and the number increase daily. We think it is worth while reviewing the piston question once more with reference to what is the best thing to do when the Moulder go back to work. 4 We recommend that we reconsider the question of using cast iron pistons or at least we ought to have a design of cast iron pistons ready and being tested in case we cannot obtain absolute silence and reliability with the aluminium. | ||