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).
Piston and cylinder dimensions, limits, and matching to achieve finer clearance limits.
| Identifier | ExFiles\Box 48\1\ Scan106 | |
| Date | 1st September 1919 guessed | |
| - 2 - to the quoted piston dimensions and limits ( this will avoid alteration to the cylinder) so as to overlap limits. At first sight it appears that the limit on the piston could be increased to 1 thousandth in lieu of the present ½ thousandth, so that the largest piston would correspond with the largest cylinder and the smallest piston with the smallest cylinder, and give the specified clearance of 9 and 6 thousandths. This is a point which perhaps it is worth your while looking into. Until you have completed your investigation into this question of matching pistons and cylinders by selection, we think that in those cases in which chasses are held up for pis-ton taps when at normal working temperature and when pistons and cylinders are within the existing drawing limits that the Test Dept. should call for pistons and cylinders which are matched to give clearances of not less than 8½ and 5½ thousandths, or more than 9½ and 6½ thousandths at top and bottom of skirt respect-ively. We feel sure that it will be a great help if pistons and cylinders can be matched up to give finer clearance limits in this way. Bn.{W.O. Bentley / Mr Barrington} Bn{W.O. Bentley / Mr Barrington} | ||