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).
Chief items at 12,650 miles for a B. IV. Bentley after a 15,000-mile test in France, which was concluded due to body and engine failure.
| Identifier | ExFiles\Box 82\3\ scan0359 | |
| Date | 4th June 1935 | |
| X200a Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux} 3/JAB 4.6.35. Please circulate & return To Sg.{Arthur F. Sidgreaves - MD} from Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux} to Wor.{Arthur Wormald - General Works Manager} to E.{Mr Elliott - Chief Engineer} to By.{R.W. Bailey - Chief Engineer} to De. to Bn.{W.O. Bentley / Mr Barrington} to Bp. to Mx.{John H Maddocks - Chief Proving Officer} to Hs.{Lord Ernest Hives - Chair} 5. B. IV. BENTLEY - 15,000 Miles in France. Report on chief items at 12,650 Miles Specification to Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer} 2/KW 2.4.35. { Owing to the deterioration of the Body, and failure of Engine, the test is concluded } E N G I N E 1) 7 TO 1 COMP. RATIO CAST IRON CYLINDER HEAD GIVING 126 BHP. The detonations became very noticeable with the increased mileage. The ignition had to be retarded 4 to 6 notches to entirely delete the detonations when accelerating from low speeds. There has been no trouble with over heating or pre-ignition. The Plugs do not show excessive burning of the electrodes. Performance has not improved with running. The Carbon deposit was normal. 2) SMALL BORE INDUCTION PIPE 1.375 DIAMETER. We have had no failure with the small bore pipe. Distribution was uneven, at slow speeds. Idling of the engine was not consistent. Slow running on the road not consistently good. The mixture was inclined to become strong. 3) CLUTCH. We have run with a fixed centre driven plate in the Clutch for 10,000 miles. On the road, there has been no sign of slipping. The engagement towards the latter end, was not smooth when using second gear. Examination of the spring loaded back plate showed that the three locating studs had chattered and caused indents in the east iron plate grooves. This would be a source of uneven taking up of the Clutch. The condition of the fabric on the driven member was very good, no appreciable wear had taken place. 4) NARROW PIN CRANKSHAFT. This shaft is worse than previous shafts for vibration periods. A load of 20 lbs was needed on the damper, to damp out the periods. The periods came in at 1,000, 2,650, and 3,600 engine revs. At a mileage of 8,300, N° 5 Connecting rod bearing seized on the Crankpin and tore up the surface. | ||