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).
Request to produce four modified Wraith III cylinder heads with smaller valves to test improvements on valve seat warping.
| Identifier | ExFiles\Box 8\6\ 06-page33 | |
| Date | 27th June 1938 | |
| 619 To HPS.{Horace Percy Smith - Experimental Factory Mgr} Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}19/JH.27.6.38. Wraith III Cylinder Heads. You will note from our report Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}15/JH.25.6.38. that we have recommended reduced size of inlet and exhaust valves on production to effect an improvement on valve seat warping that has been experienced. In view of this we should like you to produce 4 heads complete with valves in order to get some more experience as to how much improvement will be effect by this modification. The part numbers for the job are, EX.29685 Cylinder head. EX.29686 Inlet valves. EX.29687 Exhaust valves. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} | ||