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).
Engine work carried out on crankshaft and bearings at various mileage intervals.
| Identifier | ExFiles\Box 146\3\ scan0177 | |
| Date | 16th November 1936 | |
| Bentley Motors (1931) Ltd., DERBY. .................... Rm.{William Robotham - Chief Engineer} [Handwritten above reference number: 12205] [Handwritten: Piles (crossed out)] [Handwritten: Swell (underlined)] [Stamped: copy VA (illegible)] Sr/Crnl/16.11.36. Bentley bearings. ------------------ With further reference to our memo. SrIO/Crn.12.11.36, I am giving you, here-under, a translation of Chomet's report on the above matter :- B. I CW - mileage at 5/11/36 .... 68,717 kms. Work carried out to engine (crankshaft & bearings). Sept 2nd, 1935. Mileage 33,560 kms. Replaced white metal bearings (failure of white metal) by six lead bronze bearings (bearings with oil feed to conrod bearings). No examination was made of the crankshaft. April 4th, 1936. Mileage 56,780 kms. Completely dismantled the engine. Examined lead bronze bearings - found to be O.K. Slight tightening up of conrod bearings, reducing distance pieces to give .003" play. Crankshaft journals in good order - no wear since replacing the white metal bearings by lead bronze bearings. Crankshaft bearings in bad state (failure of white metal). Replaced crankshaft bearings in white metal by Halls metal. Nov 5th, 1936. Mileage 68,717 kms. Dismantled conrods to examine bearings. Big end bearings O.K. - no wear since tightening up at 56,780 kms. Crankshaft journals in perfect condition - no wear since replacement of bearings. Dismantled main bearings for examination. Bearings had commenced to hammer in their housings, particularly the rear main bearings. We found the bearings to be .002" below their normal position when topping, although we allowed the toppings, at the first building up, to overlap about .001" in order to give a perfect fit to the bearings in their housings when they were tightened up. Work effected on crankshaft - tightened up bearings by lightly filing liners. REMARKS: ------- We do not think that the tightening up of the crankshaft, by reducing the thickness of the bearing liners is a satisfactory remedy. The clearance between the main bearings and the liners still exists, and the bearings continue to hammer in their housings, resulting in wear in the crankcase. .......................... | ||