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).
Report to Borg & Beck, Ltd. regarding periodic lever flutter on a 10' C.P. clutch.
| Identifier | ExFiles\Box 130\3\ scan0141 | |
| Date | 3rd December 1940 | |
| 1110 Rm{William Robotham - Chief Engineer}/GB.1/RF. 3rd December, 1940. Your ref. Sales.2/AMS/LF. A.M. SHINKINS, Esq., Messrs. Borg & Beck, Ltd., Tachbrook Road, LEAMINGTON SPA, Warwickshire. Dear Sir, Here is our report on the periodic lever flutter on your 10" C.P. clutch. It was noted that, on cars fitted with this clutch, the pedal came up against the floorboards at the higher engine revs. One or two clutch throwout ball races have failed owing to this cause. One of these clutches was fitted to an engine on a test bed and clutch throwout race movement was plotted against engine revs. This is shown on the enclosed graph. The race movement at 3500 r.p.m. could not be measured owing to lever flutter, but it is more than at 4000 r.p.m.. At the latter revs, the period has been passed. We have tried chrome plating the lever pins to eliminate slack, but this does not reduce the severity of the period. We are to try stiffening the pressed cover next. We would like to treat clutches as follows:- On new cars, set the pedal so that there is 1 1/8" of free movement before starting to disengage the clutch. 1" of this movement is to allow for wear. (The pedal rises as the clutch wears). 1/8" of the movement is to look after the centrifugal effect of the weights. At present, increase of engine speed brings the clutch pedal up 3/8". If we give the pedal 1 1/8" of free movement, the clutch will not disengage fully. | ||