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).
Page detailing engine modifications, bearing replacement procedures, labour hours, and oil flow testing.
| Identifier | ExFiles\Box 114\3\ scan0088 | |
| Date | 4th May 1938 guessed | |
| - 2 - Either of the modifications B. or C. are invariably carried out in conjunction with an R.10 or R.20 for which the customer pays. It is recommended that when an engine is dismantled for an R.20 modification C. should be carried out. It is not good policy to effect Mod.B. in conjunction with an R.20. In fact Modification C. carried out with an R.10 which is usually needed after one year's service would in the long run be the most economical and undoubtedly the best method of dealing with the bearing problem. The comparative extra labour hours for the Mod.B. and C. are as follows : Mod.B. in conjunction with R.10 extra hours 46¾ Mod.C. " " R.10 " " 136 Mod.C. " " R.20 " " 100 With regard to material it is very seldom necessary to replace the main bearings when Mod.C. is done. In addition to the previous instructions for Mod.C. the following should be added :- (a). Adopt the Works method of forcing the bearings into the housings to ensure correct bedding of the back of the shells. (b). "Nip" - this should be .001" at each side of the bearing relative to the joint face on both halves. Before the bearing is clamped up, therefore, the bearing shells stand proud of the housings by this amount on each of the four joint faces giving a total nip of .002. (c). The No.7 main bearing should be in white metal with white metal faced steel liners. As this bearing has a steel backing there is no necessity to force the bearing in question as outlined in (a). The total nip of this bearing should not be more than .001. With regard to the oil test previously referred to, we have for a number of years used some form of oil flow test. It has been of invaluable service, particularly on aero engines as an indication of the condition of bearings, without the necessity for dismantling or re-assembling. We should profit by this experience and make more use of oil flow tests on car work. With the use of an apparatus which has already been developed by K.{Mr Kilner} the condition of the bearings in an engine can be established by a test which takes less than one hour. It has been found particularly valuable for ascertaining the condition of bearings on a car sent in for a certificate for re-sale purpose | ||