The trial of nitrided exhaust valve stems for the Phantom III to reduce sticking and noise.
| Identifier | ExFiles\Box 96\2\ scan0242 | |
| Date | 25th June 1937 | |
| To HPS. {Horace Percy Smith - Experimental Factory Mgr} from Rm {William Robotham - Chief Engineer} /Swdl. {Len H. Swindell} 354 Rm {William Robotham - Chief Engineer} /Swdl. {Len H. Swindell} 2/AP.25.6.37 PHANTOM III. We understand that the Aero people are nitriding the stems of the exhaust valves which reduces the tendency to sticking. At the present time we cannot go to a less clearance than .003" - .004" with our KE.965 exhaust valves on account of sticking. Large clearances make for noisy valve gear especially on a solid rocker gear as we are now trying on Ph.III. In view of the above will you please produce a set of valves to E.88447 with nitrided stems for trial with a diametrical clearance of .0015" - .002" in the guides. Rm {William Robotham - Chief Engineer} /Swdl. {Len H. Swindell} | ||
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).