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 modifications and performance, including changes to bearings, cushioning, and housing.
| Identifier | ExFiles\Box 91\2\ scan0351 | |
| Date | 18th September 1937 | |
| 4. The delation of the tail bearing enabled a larger Trunnion thrust bearing to be used which overcame the noise which is experienced with the standard ball bearing. also the place of the tail bearing was taken by a ball bearing carrying the clutch shaft which overcame the drag experienced with the oilite bush which previously carried it. ---------------- The clutch was exceptional in all respects, and there were no marked vibration periods that could be attributed to the deletion of the tail bearing. At no time, even with unfair treatment, could judders be produced or the clutch be made to slip. Gear changes could be made with the engine speed all wrong without any perceptible snatch. There was no objectionable smell from the Thermoid when the clutch was maltreated, and there were no squeaks on engagement as experienced with previous types of centre plate. The pedal clearance was only re-set once during the mileage and the wear of the Thermoid appeared to be hardly measurable. The compound cushioning gave a more progressive action and the engagement took place over a wider range of the pedal travel than formerly, which improved the operation Under conditions of extreme heat the trunnion tended to stick on the sleeve on which it slides. It has been agreed that slightly more clearance is required here. A ventilated clutch housing was fitted. There were no complaints of noise with this arrangement and very little dirt had entered the housing. It should be mentioned that practically no rain was experienced during the mileage, so that the effect of wet conditions on the ventilated housing cannot be given. A Standardisation sheet for the Thermoid facings and compound cushion plate has been issued. The outcome of the cheapened clutch is under discussion. | ||