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).
Slipping clutches, potential oil seal improvements, and new clutch designs for Bentley and 20/25 models.
| Identifier | ExFiles\Box 103\1\ scan0125 | |
| Date | 24th July 1934 | |
| 15300 To Wor.{Arthur Wormald - General Works Manager} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}20/KW.24.7.34. Replying to Wor.{Arthur Wormald - General Works Manager}5/R.18.7.34. We note that Hd.{Mr Hayward/Mr Huddy}. reports that 22 cars that have suffered from slipping clutches have all the known improvements. There is however one improvement which we believe has not been fitted to the cars in question, and that is a better oil seal for the rear main bearing. We understand from By.{R.W. Bailey - Chief Engineer} that this has now been fitted to over 100 20/25's. The oil seal has a bearing on clutch trouble because we think that oil vapour entering the clutch pit via the rear main bearing has a tendency to cause slipping. With regard to major alterations in design, both the Bentley and the 20/25 now running in France are fitted with clutches to N.Sch.3948. This clutch has 50% more area than the present standard clutch and in addition, the fabric can be fitted to either the driving or the driven member. The difficulty is that so far every modification we have made whereby the life of the clutch is improved has increased the tendency of the clutch to be fierce on engagement. 21-G-IV, however, is the best compromise that we know of and if the clutch is reasonably smooth when it has completed 10,000 miles it will be considered for standardisation. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||