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).
Instructions for modifying Bentley crankshafts to prevent connecting rod failures by improving lubrication.
| Identifier | ExFiles\Box 114\3\ scan0014 | |
| Date | 23th February 1939 | |
| Hd.{Mr Hayward/Mr Huddy} K.{Mr Kilner} GWH.{George W. Hancock - Head Chateauroux} Sr. c. BY/SR. c. RHC.{R. H. Coverley - Production Engineer} BENTLEY CRANKSHAFTS. In giving the question of connecting rod failures consideration, particularly the fact that 2 and 5 big ends almost invariably fail under certain conditions of running when the remaining four are quite unaffected, it is clear to me now that this is the result of a point which I have raised before but did not see the full implication of the suggestion, viz. that 2 and 5 obtain all their oil from short intermediate bearings only, whereas 1, 3, 4 and 6 are connected to one long bearing and one intermediate. To avoid this fault, I am instructing herewith that three holes instead of two of .278 diameter should be arranged for on crankshafts which have to be handled in the course of repair. Where two holes have been introduced in the intermediates, in accordance with present instructions, I wish to have two more holes, but in this case .1875" diameter, the new holes being arranged to equally divide the bearing circumferentially, that is, the four holes will then be at 90° to each other. This matter is important and urgent. BY.{R.W. Bailey - Chief Engineer} | ||