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).
Problem with seizing Spectre exhaust valves and proposing a modification to the valve stem.
| Identifier | ExFiles\Box 96\2\ scan0037 | |
| Date | 15th March 1935 | |
| from RHC.{R. H. Coverley - Production Engineer} c. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} X 35F RHC.{R. H. Coverley - Production Engineer}9/MS15.3.35. SPECTRECodename for Phantom III EXHAUST VALVES. SpectreCodename for Phantom III Exhaust Valves E.{Mr Elliott - Chief Engineer} 86289 are inclined to seize in the bottom end of the guide, and it is suggested this is due to the formation of carbon on the fitting portion of the stem which, in the closed position, projects approx .100 below the mouth of the guide. Carbon accumulating here tends to work up the guide causing the valve to bind and seizure results. It is therefore recommended that the .336 diameter relieved section above the neck of the valve should be extended slightly, as shown below, so that the whole of the stem is shrouded by the guide in the closed position, as on Phantom, 20/25 HP. and Bentley. The scrubbing action of the guide would then prevent carbon forming on the stem and it is considered this should overcome the trouble referred to. [Diagram 1 Handwritten Text] STEM AT PRESENT PROJECTS .100 BELOW VALVE GUIDE [Diagram 2 Handwritten Text] VALVE MODIFIED AS SUGGESTED ABOVE RHC.{R. H. Coverley - Production Engineer} | ||