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).
The performance and maintenance of a bypass oil filter on a 32-EX Phantom III.
| Identifier | ExFiles\Box 91\2\ scan0155 | |
| Date | 15th July 1937 | |
| CHATEAUROUX. 300a Rm{William Robotham - Chief Engineer}/IMW{Ivan M. Waller - Head of Chateauroux}/G/JAB.15.7.37. To. Rm.{William Robotham - Chief Engineer} c.c. Rm{William Robotham - Chief Engineer}/Swal. c.c. Rm{William Robotham - Chief Engineer}/CWH. 32-EX. PHANTOM III. Bye-pass Filter. The Castrol "CW" oil in this engine had covered 6,640 miles in England and France. Samples taken after 3,400 miles showed the oil to be dirty, also there was no perceptible difference between the oil collected from the outlet from the filter and that in the sump. The outlet pipe was then modified as previously reported. At 5,180 miles, the flow through the filter had considerably diminished. There was still no noticeable difference between the oil from the filter and the sump, but it was not appreciably dirtier than at 3,400 miles. We have been waiting for the oil promised from England before draining down and refilling, and using some old "CW" (before "Patent" Castrol) for replenishments. We decided in view of the dirty state of the oil and reduction in flow from the filter to wait no longer, so we drained down after 6,640 miles and refilled with Castrol "XL". We have also fitted a new filter element and returned the dirty one for your inspection (in same package with a shock damper). It should be noted that changing the element is not as simple a job as we were given to believe. It is necessary either to remove the exhaust manifold, or else the filter and engine side shield. The sump of the filter contained quite a lot of dirt indicating that the filter must be doing some good. The element had already covered 2,092 miles before the engine was filled with Castrol "CW" in Derby. ----- P.S. Will you please send us another spare filter element. Rm{William Robotham - Chief Engineer}/IMW.{Ivan M. Waller - Head of Chateauroux} | ||