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 report on a Bentley Trials Saloon (B.2.LS) following a piston and big end bearing failure.
| Identifier | ExFiles\Box 88\2\ scan0243 | |
| Date | 19th July 1938 | |
| To Sg.{Arthur F. Sidgreaves - MD}.. from BY.{R.W. Bailey - Chief Engineer} c. Rm.{William Robotham - Chief Engineer}. c. Hd.{Mr Hayward/Mr Huddy} BY.23/N.19.7.38. Bentley Trials Saloon - B.2.LS. Referring to Sg.{Arthur F. Sidgreaves - MD}22/KW.12.7.38, which I regret pressure of other work prevented me from reporting upon towards the end of last week, by which time I had obtained the necessary information. The facts of the case were that the piston was broken to pieces, and the No.6. big end bearing had completely melted out. From an examination of the parts it is quite clear that the piston was the result of and not the cause of the accident. This was obvious from a close examination of the pieces of the piston which had been salved. In examining the crankcase and main bearings it was found that No.7. 6. and 5 bearings had excessive sinkage effects, the total increase being: (a) No.7. .028" (b) No.6. .022" (c) No.5. .018" The remaining four had standard running clearance. The chassis in question is one of those fitted with AC.2. main bearings, but I am not inclined to think this was the actual cause of the trouble. The car was examined in March after 10,000 miles, and the main bearings were then all perfectly good, and the bearing clearances were normal. What astonished me is that it was possible for a Trials car to have practically 1/32" vertical slack on No.6 and 7 bearings, and yet the car was not reported by the Driver for "thudding" or "roughness". My view is that at some point between the examination at 10,000 miles and the present time, the car has been run on third gear at high speed, which has caused Cont'd... | ||