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).
Modifications to valve stem diameters for the Phantom III and 25-29 HP models.
| Identifier | ExFiles\Box 96\2\ scan0064 | |
| Date | 26th September 1935 | |
| Lt Smith - Please supply Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} F.2/HP.26.9.35. Rm{William Robotham - Chief Engineer} Phantom 3 Valves. ---------------- Replying to your memo Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}15/KW.17.9.35, I have already decided to increase the exhaust valve stem diameter, and have added .032". At the same time for the sake of interchangeability of the guard rings and other small pieces I am making the inlet valve stem to the same increased diameter. The inlet valve is of course larger and will carry a larger stem. At the same time the head is made much thinner than the exhaust and its total weight should be no more. I should be glad if you could supply me with the respective weights of the present inlet and exhaust valves. The modified valves are shown on LeC.4711. A similar modification is being instructed for the big bore 25-29 HP. and is shewn on LeC.4720. The attached table shows the various valves with the proportionate increases we have adopted. ATT: E.{Mr Elliott - Chief Engineer} | ||