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).
Dismantling a B. 56. BN Bentley engine due to severe thudding and bearing issues.
| Identifier | ExFiles\Box 83\4\ scan0175 | |
| Date | 25th April 1936 | |
| HOTEL DE FRANCE. CHATEAUROUX. Indre. France. GWH{George W. Hancock - Head Chateauroux}/5/JAB. 25th April 1936 To. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} From. G.W.H. B. 56. BN.{W.O. Bentley / Mr Barrington} - BENTLEY. We have dismantled the engine to examine the bearings and pistons. The engine was thudding very bad during the run from Paris. The connecting rod bearings do not show any sign of cracks but the bedding surface does not show a full bed on the bottom caps. The sketch gives an approximate view of the bottom caps. The main bearings, N° 6 especially, show very bad groove marks and the crank bearing is ringed. N° 1 is similar but not to such an extent. The intermediate bearings and centre are also grooved. The centre and one and seven are dirty and pitted. The alignement of the pistons with the cylinders has not been true. Nos. 6, 5, 3, & 2 pistons show very heavy score marks on the top land of these pistons and the bearings show a heavy side thrust showing out of alignement. I have not seen cylinder bores so chattered at the top as Nos. 6, 5, 3, & 2 are. The Valves were not in a bad condition, most of the Exhaust had been bottoming but had not dug in. Upon going over our valve chart, the stretch so far has been N° 1, .001, N° 7 .001, N° 10 .002, N° 11 .003. The others have not shown any increased clearance. We are dismantling the Clutch and shall fit the plate sent out. Particulars of the clutch we cannot give until dismantled. RE PROPELLER SHAFT. The Hardy Spicer Shaft on our car has no flange on the Gear box end to fit the damper, so it will not be possible to do as you suggest. ------------- G.W.H. | ||