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).
Lead bronze bearings, oil pressure, and bumper bars for Bentley vehicles.
| Identifier | ExFiles\Box 27a\1\ Scan237 | |
| Date | 6th February 1935 | |
| L4013 To Sr. from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}14/KW.6.2.35. Lead Bronze Bearings for Bentleys. Replying to Sr/WHA.5/ET.4.2.35, on our 10,000 miles tests in France our big ends fail after about 12,000 or 13,000 miles' running. If you want to be on the safe side you should look at your big end bearings after 12,000 miles, and if they show signs of failing you can replace them with lead bronze. With regard to the query re oil pressure. When starting up from cold the oil pressure with the large pump and lead bronze bearings will go off the scale, but once the engine has become thoroughly warmed up it should be as it is at present, i.e., about 30 lbs., except when idling, when it will fall to 15 lbs. The object of the larger oil pump is not to increase the normal running pressure, but to prevent the pressure falling when the oil gets hot. With regard to bumper bars, supplies are now available for production, and we will ensure that some are sent over to you almost immediately. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||