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).
The difficulties of using Bentley-type pistons and outlining experiments with alternative piston designs.
| Identifier | WestWitteringFiles\D\December1919\ Scan25 | |
| Date | 29th December 1919 | |
| To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. c. to BR.{T. E. Bellringer - Repair Manager} c. to K.{Mr Kilner} c. to DA.{Bernard Day - Chassis Design} c. to EP.{G. Eric Platford - Chief Quality Engineer} CK{Mr Clark} ORIGINAL BENTLEY-TYPE SPRING PISTON MENTION OF 2EX "THE 10,000 MILE CAR" HsB/L.G.29.12.19. X.2448 RE PISTONS. X.3432 X.3454 The proportions of our piston and connecting rod do not lend themselves to the Bentley type of spring piston; the gudgeon pin boss being so low down, there is no room to get the flexible band in the bottom of the piston like what is used on the Bentley pistons. It would be no use extending the skirt of the piston to get this flexible band on because our piston already extends out at the bottom of the cylinder when the piston is at the bottom of the stroke. I spoke to Capt. Bentley about this piston recently in London and he said that our proportions would make it difficult to obtain the best results. We are sending a drawing of a standard piston to see what they can recommend. We have found it is possible to re-set the split aluminium pistons when the clearances have increased. This we have done by peaning them with a hammer on the non-pressure side. We are running a car with pistons treated in this way and so far it has run 150 miles quite satisfactorily. We are about to try a set of condemned solid type pistons. We shall split them and then pean them out with a hammer to give them the desired clearance. We have got some castings of the improved type split pistons on which the metal is better distributed on the non-pressure side to form the spring. These look very promising. (Contd). | ||