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 valve mechanism trouble and misfiring on a PIII model during a cold start.
| Identifier | ExFiles\Box 96\2\ scan0179 | |
| Date | 9th December 1936 | |
| To RM.{William Robotham - Chief Engineer} Redes 354. 9/12/36. Trouble Valve Mechanism on PIII While Starting from Cold. Considerable trouble has been experienced with misfiring on the PIII while starting up from cold. To determine the exact cause of the trouble the following experiments with the aid of a rig have been completed. 1) The rig was fitted with a standard quarter shaft and Rockers eccentrics and bushes complete and left out all night in the frost. The next day a close inspection of the Valve mechanism while in slow motion showed clearly that the eccentrics were dragged round by the motion of the rockers while opening the valves. In so doing the spring loaded plungers followed the eccentrics. It is obvious that the plungers will not return to their original position owing to the non return valve inside the plunger. And consequently if the efficiency of the non return valve is good and the oil cannot leak past the plunger. The Valves will be held off their seats and remain so until the plungers have been released by hand. | ||