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).
Recurring bearing failures on a 3½ Litre Bentley and the debate over repair methods.
| Identifier | ExFiles\Box 114\3\ scan0074 | |
| Date | 20th September 1938 | |
| To By... from Rm{William Robotham - Chief Engineer}/GWH.{George W. Hancock - Head Chateauroux} Rm{William Robotham - Chief Engineer}/GWH.{George W. Hancock - Head Chateauroux}21/N.20.9.38. Re: 3½ Litre Bentley - Bearings. Re the conditioning of bearings during an R.20 and the advisability of fitting the increased capacity oil pump. I would like to bring to your notice a case that is being dealt with at this Depot, which substantiates our experience, but which Derby have not agreed with. The case in question is G.Eyston's Bentley B-24-DG. The history of this car is as follows. At 13,000 miles the car was returned to Derby for various faults, chiefly period in engine. The engine was not satisfactory after a considerable amount of work carried out, and a new engine was fitted (Aug.1936). After a further mileage of 31,312 the con rod bearings had broken up (17.12.37). A Mod.C. was carried out and new bearings fitted, the small oil pump being retained owing to Hm{Capt. W. Hallam - Head Repairs}'s memo Rm.{William Robotham - Chief Engineer}16/MH.{M. Huckerby}28.10.37. The car is in again after a further mileage of 16,504 for an R.20. Examination of the bearings makes it impossible to refit them. Three of the con rods are broken up, flanges at the side broken off, the remaining being cracked. The metal deposited in the oil has ruined the journal bearings, therefore, a complete new set of bearings are being fitted, but I am taking the responsibility and fitting Halls metal to the con rods and having the increased capacity oil pump fitted. The points I wish to raise are: We at Kingsbury did not agree to going back to white metal on the 3½ litre for con rods, having seen sufficient evidence to justify our opinion, but we were not asked or consulted at the meeting when Rm.{William Robotham - Chief Engineer} and Hd.{Mr Hayward/Mr Huddy} ruled that [strikethrough] white metal should be used in future for 3½ litre con rods. The truth of the matter being that neither of them knew what was wrong with Halls metal. We had at that time learnt what was wrong ( i.e. the correct fitting of the shells and the correct bearing clearance. We were also of the opinion that the increased capacity oil pump was necessary but Hm{Capt. W. Hallam - Head Repairs}'s memo sent out on 28.10.37 cut this out. | ||