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).
Examination of failed Bentley engine bearings from trials cars, identifying two separate issues.
| Identifier | ExFiles\Box 115\1\ scan0083 | |
| Date | 26th September 1936 | |
| To Sg.{Arthur F. Sidgreaves - MD} from Rm.{William Robotham - Chief Engineer} c. to Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} c. to By.{R.W. Bailey - Chief Engineer} X1020 Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}3/KW.26.9.36. Bentley Engine Bearings. Further to Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}1 KW.19.9.36, we have now had an opportunity of examining both the trials car bearings which have completed 24,000 miles in England, and Sr's trials car on which the big end failed. From these sets of bearings we have decided that there are 2 separate issues with regard to the trouble which has been experienced - (1) The shim which separates the two bearing halves is a steel piece lined with Hall's alloy. We always had very great difficulty experimentally in getting the alloy to stick to the steel, and in production apparently good adhesion is not a practicable proposition. The result is that in both cases the Hall's metal bearing has broken away from the shim, and spoilt the big end bearings. E.{Mr Elliott - Chief Engineer} By.{R.W. Bailey - Chief Engineer} and Rm.{William Robotham - Chief Engineer} have agreed that we should put forged shims in R.R. alloy on production as soon as we have done sufficient experimental running. We are urging the necessary tests. (2) The slack in the rear main bearing does seem to develop on the new bearing alloy in about 15,000 miles if the car is driven to capacity. It should be appreciated, however, that 6-B-IV has now completed 15,000 miles in France on its original main bearings. These are now being stripped for examination. There are several sets on test which give promise of improvement, but a great deal of testing will be required before we can change them on production. What we can do immediately is to improve the oil supply to the rear main bearing. | ||