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).
Bearing failures caused by using thin oils and the importance of cleaning suction strainers.
| Identifier | ExFiles\Box 145\3\ scan0214 | |
| Date | 12th December 1940 | |
| W/N. Br.{T. E. Bellringer - Repair Manager} from Rm.{William Robotham - Chief Engineer} c. Hd.{Mr Hayward/Mr Huddy} Rm.{William Robotham - Chief Engineer}16/ML.12.12.40. 1235 THIN OILS. We have investigated the failure of the bearings on Br's Bentley, and have come to the conclusion that the trouble is due to the fact that we put S.A.E. 20 oil into this engine after we had decarbonised it. This is because at present, we use nothing but this viscosity oil in the Experimental Shop. We have already pointed out the dangers of using thin oil when the car is driven hard, in Depot Sheet By.6. of 22.2.39. and that nothing thinner than a "30" oil should be used in chassis previous to B-2-MR. (Depot Sheet No: Hd.{Mr Hayward/Mr Huddy} 387, reference Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls}6/MH.{M. Huckerby}24.5.38) Our experience with Br's car, however, has emphasized the danger of using S.A.E. 20 on old type Bentleys. Another point has arisen in connection with lubrication, and that is that when a by-pass filter is fitted, the customer is apt to continue running for a long period without cleaning his suction strainer. The importance of cleaning the suction strainer was mentioned in Depot Sheet Hd.{Mr Hayward/Mr Huddy} 399 of 8.12.38., but we have recently experienced a case where the oil pressure failed completely due to the suction strainer being clogged, in spite of the fact that the oil was as clean as when new because a by-pass filter was fitted. Whenever therefore, the instructions contained in Depot Sheet Hd.{Mr Hayward/Mr Huddy} 399 are carried out, the fact that the suction strainer must be cleaned every 10,000 miles, should be impressed upon the customer. Rm.{William Robotham - Chief Engineer} | ||