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).
Clutch oil leak, damper unit, and carburation issues for a B. 56. BN. Bentley.
| Identifier | ExFiles\Box 83\4\ scan0179 | |
| Date | 27th April 1936 | |
| Gry{Shadwell Grylls} YC INTA FB Hs.{Lord Ernest Hives - Chair} X264a HOTEL DE FRANCE CHATEAUROUX. Indre. France. To. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} From. G.W.H. B. 56. BN.{W.O. Bentley / Mr Barrington} BENTLEY. CLUTCH The dismantling of the Clutch has given us proof of the increased jaggers. Oil has got on to the fabric on the pressure plate side. The flywheel was perfectly dry, and the fabric in contact with the flywheel face is entirely free from oil. The interior of the clutch casing was smothered in oil, and the oil was clean. This indicates that it is not engine or gear box oil. It looks suspiciously like bijur oil. The only places where this can come from are, trunion feed, clutch trunion shaft and the equalising shaft bearings for the foot brake. We fixed up a bijur pump and tried these points to ascertain whether any undue amount of oil was escaping into the clutch case, but we could not get any sign of excess. To make sure of this however, we are cutting off the bijur supply to these parts for the time being, to ensure that no bijur oil can enter the case. The condition of the clutch otherwise was good. There is no wear on the clutch case where the lugs take the drive. The springs, driving and damper are in a good condition. Clutch was free on the splines. The bearing in the gear box of the clutch shaft may be slacker than what one would desire, but as this is supported in the flywheel, one cannot be certain of the slackness. The oil to get on the front fabric face has apparently entered the clutch casing by the slots for the driving lugs and when stationary, ran down the pressure plate and on to the fabric. We could not observe any other place where the oil had entered. There was no sign of the oil having run down the flywheel face. To take care of the aforesaid trouble, we would recommend that the inner edge of the castiron pressure plate should be turned or shampered so that the oil would run away from the fabric. This you may say would form a high point for the oil to be flung off at speed, but the trouble in our opinion is when the engine comes to rest, when the oil runs downwards. We have received the coiled pipe for the damper unit complete with valve. These are being fitted. We are also fitting a baffle plate in the lower half to prevent the oil being swished out of the rear due to the increased acceleration, details of which will be sent if proved satisfactory. CARBURATION We would like to point out that slow running is ruined by poor petrol pumps. If there is any leak past the valves or the diaphram, the pump pulsates fairly often (approximately every five seconds) while the engine is idling. | ||