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).
Valve seat warping in the Wraith III cylinder head, proposing new valve specifications for experiment.
| Identifier | ExFiles\Box 10\3\ 03-page155 | |
| Date | 25th June 1938 | |
| 654 To By.{R.W. Bailey - Chief Engineer} c. to RHC.{R. H. Coverley - Production Engineer} c. to Da.{Bernard Day - Chassis Design} c. to Mx.{John H Maddocks - Chief Proving Officer} c. to HPS.{Horace Percy Smith - Experimental Factory Mgr} c. to Da{Bernard Day - Chassis Design}/MGS. c. to By/WS. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}15/JH.25.6.38. WRAITH III VALVE SEAT WARPING IN CYLINDER HEAD. Further to our report Rm.{William Robotham - Chief Engineer}1/R.20.6.38. recommending the adoption of smaller valves i.e. 1.5 dia. inlet and 1.3 dia. exhaust, we have checked over the comparative shape of inlet valves and find the Phantom III tulip type is the best as shown on attached curve with regard to performance. The valves recommended therefore are - Exhaust EX.29687. Inlet EX.29686. which should be detailed to BW numbers and instructed for production to effect an improvement on the valve seat warping trouble that has been experienced, until such time that a cure can be made and recover the lost power through small valves. We should like two heads as follows, designed and detailed for further experiment in connection with this job. 1st. head. (a) EX.29687 1.3 dia. exhaust valve with its centre spread .075 from existing position. (b) EX.29686 1.5 dia. inlet valve with Phantom III type of tulip head on existing centres. (c) Water spacing brought down as shown on EGD.704. In order to avoid handed rockers the exhaust water tubes could be spread to the best davantage by .0375 and by alteration to the rocker pedestals and distance pieces, common exhaust and inlet rockers used as at present. We consider that the slight amount of inline the exhaust push rods will be subjected to by the spreading of the exhaust valve centre will be satisfactorily catered for in the | ||