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).
Differential thermal expansion in a high-powered engine with an aluminium head and cast iron block.
| Identifier | ExFiles\Box 134\2\ scan0131 | |
| Date | 2nd September 1937 | |
| Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} from Rm.{William Robotham - Chief Engineer} c. Ry. c. Jnr.{Charles L. Jenner} c. Rm{William Robotham - Chief Engineer}/Ed.{J. L. Edwards} 1129 Rm{William Robotham - Chief Engineer}11/R.2.9.37. When we come to the high-powered engine, we shall have an aluminium head and a cast iron cylinder block. We know from our experience on P.III that this will give us a maximum amount of differential expansion between the push rod and the engine. We should like someone to make an analysis to say what this differential expansion is likely to be as a maximum, and whether we can deal with it by a camshaft toe similar to that used on 32-EX. Incidentally, we presume it would be better to follow P.III practice and use a duralumin tube push rod. If this is so, room should be allowed for such a push rod in the design. The rocker ratio will, of course, have an effect on this problem. We do not expect to have an oil cooler on this engine, and so the oil will not follow the water temperature as quickly as it does on P.III. Rm.{William Robotham - Chief Engineer} | ||