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).
Investigation into the cause of piston knocks, detailing tests on an overoiler and bearing examination.
| Identifier | ExFiles\Box 48\1\ Scan186 | |
| Date | 16th September 1926 | |
| X4190 "Hs{Lord Ernest Hives - Chair}" Derby "Rm{William Robotham - Chief Engineer}" Derby PS2/JP.16/9/26 RE PISTON KNOCKS. Your "Hs{Lord Ernest Hives - Chair}/RM{William Robotham - Chief Engineer}6/LG10/9/26" to hand, and remarks re above noted. Concerning the "Lorraine", I have written to them for the conditions and specifications, but have not yet received a reply. Concerning the overoiler, I carried out two experiments this week with oil 50° cent. First test by running engine via starter oil poured out chiefly Nº5, Nº2 runing it a good second. Second test soldered up intermediate bearing main oil supply pipes, and run engine; little or no difference in the amount of oil pouring out of Nº5 and Nº2. There is something funny about this case because Nº5 has never given trouble, Nº2 being the culprit. I now think the trouble may lie in the fit of the piston. I am now taking the engine out of frame and intend to rebed all bearings carefully, after which I shall carry out similar tests as above. I have already examined the main bearings and they leave a lot to be desired. They are a poor job generally. Ps. PS-I am interested in the small plane competition. How are you getting on ? 9-30 20-9-26 | ||