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).
Performance and material properties of main bearing alloys used in Bentley engines to address hammering out issues.
| Identifier | ExFiles\Box 115\1\ scan0342 | |
| Date | 29th May 1937 | |
| To Hs.{Lord Ernest Hives - Chair}, from Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} 10.20 c.c. to RHC.{R. H. Coverley - Production Engineer} c.c. to By.{R.W. Bailey - Chief Engineer} c.c. to Hl. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}9/AP.29.5.37 BENTLEY BEARINGS. Examination of the main bearings in A.C.2. after 17,000 miles in 3.B.lV. reveals that no hammering out has taken place and the shells are as tight in the housings as when first fitted. Hammering out has been a source of trouble on 4¼ Bentleys with the standard A.C.7. main bearings which causes excessive clearance and creates engine thump and roughness. The main difference in the two alloys is that the A.C.2. (2¾ tin) has a Brinell of 80 - 85 in comparison with standard A.C.7. (7% tin) having a Brinell of 45 and thus by its increased hardness resists the hammering out. A Standardisation Sheet has been issued and we should like to get these on Production as soon as possible. Following inspection of the bearings by all concerned, we are handing Hl. several of these bearings for analysis in order to confirm that we go into Production with precisely the same analysis and treatment as these have been given. This applies only to the main bearings, the big ends being unaltered from the present material. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} | ||