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 the Phantom and Wraith valve gear for improved lubrication.
| Identifier | ExFiles\Box 10\3\ 03-page083 | |
| Date | 1st October 1937 | |
| 654. To By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} c. By/CS. Phantom and Wraith Valve Gear. Further tests on the Phantom valve gear with solid rockers indicates that we have been on the low side regarding the oil supply to the push rods and valve tips. This has shown up on a unit where the diametrical clearance of the rocker bushes on the shafts was on the low limit side i.e. .002". By slight modifications, the supply has been corrected and we should like you to include the alterations for the production of the Phantom solid rocker gear, likewise these modifications should be applied to the Wraith, which has the same system. (1) Present .062 dia. holes in rocker shafts (E.89152) increased to .075 dia. (2) The dimension of rocker bush bore E.89154/5 when reamed in position is .601+1/4 dia. and the rocker shaft E.89152 .599-1 dia. giving a nominal clearance of .002 and .004 to the maximum limits. Will you please modify these dimensions to give a nominal clearance of .003 still with the same minimum of .002 and maximum of .004. In this way the average clearance on rockers produced will be higher and more consistent, than before and give a more satisfactory lubrication. The dimension could be as follows:- Rocker shaft E.89152 - .598 ± 1/2 Bore of rocker bush E.89154/5 in position - .601 ± 1/2 Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} | ||