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).
Expansion and necessary clearances for aluminium and cast iron pistons.
| Identifier | ExFiles\Box 35\2\ scan 083 | |
| Date | 27th June 1919 | |
| R.R. 226a (100 T) (S.E.S. 576, 16-4-19) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2354 To R.{Sir Henry Royce} from EH. c. to CJ. c. to BN.{W.O. Bentley / Mr Barrington} c. to E.{Mr Elliott - Chief Engineer} c. to BY.{R.W. Bailey - Chief Engineer} c. to DA.{Bernard Day - Chassis Design} RE PISTONS. X.2748. Attached herewith is a chart which shews the expansion on different aluminium and cost iron pistons. The pistons were heat treated 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 E.17764 is the present standard. The clearance we find necessary on this piston are as follows:- .018" Taper .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 pistons E.4237 runs with the following clearances:- Contd. | ||