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 expansion and necessary clearances for aluminium and cast iron pistons, including a diagram with measurements.
| Identifier | ExFiles\Box 180\M3\M3.7\ img006 | |
| Date | 27th June 1919 | |
| To R.{Sir Henry Royce} from AH. c. to FCR. c. to EWH. c. to L. c. to BY.{R.W. Bailey - Chief Engineer} c. to DA.{Bernard Day - Chassis Design} ORIGINAL. EH2/LG27.6.19. 27th. June 1919 RE - PISTONS. X.2448 Attached herewith is a chart which shews the expansion on different aluminium and cast iron pistons. The pistons were heated in a bath of hot oil, we stopped up the oil return holes in the pistons so that the inverted piston was full of oil at the desired temperature whilst it was being measured. The aluminium piston K.17764 is the present standard. The clearances we find necessary on this piston are as follows:- [Handwritten diagram annotations] Taper .018" .008" Taper .005" The clearances we can run with compared with the expansion of the piston shews that the piston must work at a very cool temperature on the fitting portion. The appearance of the piston after running is that it is bedding from top to bottom. The cast iron piston K.4237 runs with the following clearances:- Contd. | ||