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 results of endurance testing on pistons for two different engine units.
| Identifier | ExFiles\Box 86\2\ scan0066 | |
| Date | 21th September 1933 | |
| To RHC.{R. H. Coverley - Production Engineer} From Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}2/KT. 21.9.33. PISTON TESTS. We have now completed endurance running on pistons with various bedding on two of our engines. B.I. Unit. This engine has been running with pistons having 20 HP. land clearances with the exception that the bottom land is increased to 3.240" diameter; the skirt is to Hs.{Lord Ernest Hives - Chair}1107. In effect this is a piston with top land sizes to prevent the skirt from fracturing and a skirt diameter to give the best possible bedding. We should like to examine these pistons and then replace for further running. At the same time we should like a further .002" slack introducing between the cam wheel and crank pinion to that we can continue our tests on the balanced cam. Up to date we have run it with the clearance increased from .002" to .004" and find the silencing cam capable of dealing with this amount of back lash. C.XI. Unit. This unit has been fitted with pistons out of GWH{George W. Hancock - Head Chateauroux}'s unit. These are to Hs.{Lord Ernest Hives - Chair}1107. They have now run 8 hrs. endurance and require inspection before running further. As soon as we have had a look at them, we should like the engine to be rebuilt for further test. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||