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).
History and experimental use of hydraulic tappets on the Phantom III engine.
| Identifier | ExFiles\Box 96\2\ scan0136 | |
| Date | 9th September 1936 | |
| X354 [Signature] Swdl{Len H. Swindell} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} from E.{Mr Elliott - Chief Engineer} c. Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} By.{R.W. Bailey - Chief Engineer} Da.{Bernard Day - Chassis Design} MX.{John H Maddocks - Chief Proving Officer} Hs{Lord Ernest Hives - Chair}/Swdl.{Len H. Swindell} E/JNR.{Charles L. Jenner} E/Psn. E.6/HP.9.9.36. Hydraulic Tappets on Phantom III. We are very interested to receive the results of the experiment discussed with you in connection with the above, as given in your memo Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}3/KW.2.9.36. The question of the use or not of hydraulic tappets has a somewhat chequered history. It will be remembered that we never succeeded in quietening the tappets of J.III engine until we added hydraulic tappets, but presumably the answer to this is the dashboard insulation. Some time ago last year we got very enthusiastic to try and get rid of the hydraulic mechanism on the Phantom III engine, but at a meeting we held with all the Experimental people who had had any experience on this matter it was definitely said that we could not do without the automatic adjustment. At that time we were considering a scheme in which the clearance was transferred to the camshaft chamber by reversing the tappet spring. The reason I am recalling the past is so that we bear in mind all the previous experience gained. Personally I think we should use every effort to simplify the valve gear and if as the prospect appears we can hold the clearance on the exhaust valve to a maximum not exceeding .007 there is reasonable chance of getting the valve gear sufficiently quiet relative to the occupants of the car. Whether the standard of silence would be sufficient externally can be decided by experiment. We should like to have similar figures for the inlet valves as it may be necessary to use push rods of different materials for the exhaust and inlets to which we can see no objection as we should anticipate being able to make provision for rendering the assembly fool-proof. [Handwritten on left margin]: Release supply | ||