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 report detailing a N°5 big end bearing failure, including crankshaft and bearing measurements.
| Identifier | ExFiles\Box 146\1\ scan0296 | |
| Date | 30th June 1938 | |
| A case where Halls metal big ends have been fitted without drilling crank, grooving, or fitting large oil pump. To Bentley Motors Ltd. Derby Copy to Rm.{William Robotham - Chief Engineer} Levallois Re: CHASSIS B.101.EJ - Mr. CLOTEAUX Total mileage as per speedometer reading: 29.827 miles. During a long run in very hot weather a short time ago, N°5 big end bearing failed, and then the connecting rod, which very unfortunately has almost wrecked the engine of this car. The customer has informed us that, at the time of the failure, the engine speed was about 3800 r.p.m. He said that, as he was driving with the cut-out open, he did not hear anything until the failure of the connecting rod occurred. We have dismantled the engine and ordered the necessary replacement parts from the Works. The following is our report upon the engine: 1 2 3 4 5 6 7 Diameter of the crankshaft main journals.......... 2.247 2.247 2.247 2.2465 2.247 2.2475 2.247 .246 .246 .246 .2455 .2465 .247 Ovality............... .001 .001 .001 .001 .0005 .0005 .000 Diameter of crankpins........... 1.998 1.998 1.9975 1.9975 1.998 1.9975 x .996 Internal dia- meter of main bearings............ 2.2495 2.250 2.250 2.250 2.2505 2.251 2.250 Bow at centre of crankshaft = .006" Main bearings: White metal (original). Condition of surface very good. Slight cracks in the lower halves of N°4 & 5. Big end bearings: Hall's metal with RR.56 liners. Condition of surface very good on Nos. 1,2,3,4 and 6. We fitted a set of connecting rods with Hall's metal bearings to this car during an R.20 engine clean on 13.5.37, at 19.919 miles. | ||