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).
Modification to address overoiling issues in the Phantom III engine.
| Identifier | ExFiles\Box 96\2\ scan0274 | |
| Date | 26th November 1937 | |
| To By.{R.W. Bailey - Chief Engineer} c. to Hd.{Mr Hayward/Mr Huddy} c. to BR.{T. E. Bellringer - Repair Manager} c. to La.{L. A. Archer} 354? Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}10/JH.26.11.37. PHANTOM III OVEROILING. With reference to the complaint of overoiling causing smokey exhaust and oiled up plugs as per example the attached complaint on 3.BT.{Capt. J. S. Burt - Engineer}17 (Bernard), we would suggest that the oil supply to the rocker mechanism be reduced as follows and tried out before going to the expense of fitting new valve guides at a cost as quoted of £11.7s.6d. The modification consists of having a .075 dia. single hole in both the inlet and outlet banjos (E.76929) connected to the tappet filter in place of the existing 2 - .156 dia. holes in each banjo. This reduced supply was tried experimentally to prolong the periods between the necessary cleaning due to being silted up, by virtue of having a reduced quantity of oil to deal with. The attached photograph indicates that with the reduced oil supply the filter would last over longer periods before becoming silted up, although unfortunately we had to part with 33.EX before we had completed the 5,000 miles. 33.EX filter had the reduced supply and 36-EX the standard supply. Other than for reason of prolonging the life of the filter, La.{L. A. Archer} tried this modification on a production car which was smoking in the exhaust and reports that this is cured. There is still a sufficient supply not to be detrimental to the working of the valve gear. We would like this tried out on cars with overoiling trouble and would be prepared to issue a depot sheet and standard-ise if effective. The only danger is that the small holes in the Banjos may get blanked up, this however is of no more consequence than the filter getting choked as the tappets coming up noise give the lack of oil warning. If adopted then a note should be added in the instruction | ||