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).
Letter detailing the results of initial tests on oil filters and cartridges.
| Identifier | ExFiles\Box 135\3\ scan0160 | |
| Date | 4th August 1937 | |
| Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}7/AP. August 4th 1937 Jervis B.Webb, Esq., General Filters Inc, 9001 Alpine Avenue, DETROIT. U.S.A. Dear Sirs, We thank you for the six filters and six extra cartridges received from you and for which we have instructed a covering order. We have carried out some initial tests with the original filters received and are somewhat disappointed with the results obtained to date. In view of the above we give you details of our test and the 'set up' of the filter, from which we hope you will be able to give your opinion as to whether they are being run in the most efficient manner. Regarding the 'set up' of the filter we have adhered to the conditions of your pamphlet, that is, the inlet pipe is ¼ copper tube and the outlet 5/16" copper tube. The pressure feed varies between 5 lbs. sq.in and 15 lbs.sq.in. dependent upon the conditions of temperature and speed, the outlet being returned back to the sump via the oil filler cap, there being no back pressure, also the flow can be observed. This filter is being tested on our 12 cylinder 7½ litre unit which has a sump capacity of 2 gallons and an oil pump circulation flow of approximately 9 gallons/min. The history of the test as being carried out abroad is as follows, Commencing with new Castrol CW. oil in conjunction with the new filter, samples of oil taken after a period of 3,500 miles shewed the oil to be dirty with no perceptible difference in condition between the oil flowing from the filter and the oil in the sump. At 5000 miles the flow through the filter had diminished considerably, the oil being in approximately the same condition as at 3,500 miles. A new filter element was fitted but unfortunately the oil was also drained and the unit filled with new oil. continued | ||