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).
Valve spring, propeller shaft, and clutch juddering issues, including proposed solutions and tests for Bentley cars.
| Identifier | ExFiles\Box 30\2\ Scan366 | |
| Date | 3rd May 1934 | |
| (3) E/Lid.{A. J. Lidsey}1/HP.3.5.34. -------------------- the remaining spring is overstressed and breaks, allowing the valve to drop in the cylinder. K.{Mr Kilner} said he was issuing a design incorporating both double valve springs and a locking ring. Wor.{Arthur Wormald - General Works Manager} said that this trouble should be overcome as early as possible and before the next 10,000 miles car started running. With regard to the second complaint, Rm.{William Robotham - Chief Engineer} stated that there were actually two troubles, one at high speeds when the car is driving the engine, the throttle being closed, and which was evident in the form of a rattle; there was a cure for this in the form of a damper bolted to the propeller shaft; this was in use on Lp{Mr Lappin}'s car. The second clutch complaint is juddering when starting from rest and although the clutch is the same as we have used for years on the 20/25 HP. car it was worse in this respect on the Bentley because of the higher 2nd gear ratio, more flexible transmission, engine with lighter flywheel and more vigorous power impulses at low speeds. The damper on the propeller shaft will not remedy this. Sg.{Arthur F. Sidgreaves - MD} asked if the new clutch with increased area of friction surfaces etc. would overcome this complaint. Hs.{Lord Ernest Hives - Chair} said that the new clutch is running on 21-G- IV and the present indications were that it was no better in this respect than the standard clutch, although they had not yet exhausted all its possibilities. K.{Mr Kilner} said he would like to see the 'DON' flexible clutch centre applied to this clutch and tested. Wor.{Arthur Wormald - General Works Manager} said if there was any prospect of applying this new clutch to the 'C' series Bentley cars. Rm.{William Robotham - Chief Engineer} said that even if the new clutch was made to work better than the present one it would not be possible to incorporate it on 'C' series because it required a standardisation test. He said they were experimenting with various loadings of clutch spring centres and types of clutch linings on the standard clutch, in order to overcome the trouble of juddering. Wor.{Arthur Wormald - General Works Manager} said that he regarded this as a very serious complaint and suggested that all clutch material should be held up for 'C' series for as long as possible in order to give the Experimental Department further time to find a solution to the problem. This was agreed to and Wor.{Arthur Wormald - General Works Manager} asked E/Lid.{A. J. Lidsey} to find out how long it will be possible to hold up material for the clutch without upsetting the continuity of output. | ||