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).
Adjustment of clutch brakes and related issues with gear changing.
| Identifier | ExFiles\Box 74\2\ scan0210 | |
| Date | 27th April 1921 | |
| X.3339. R.{Sir Henry Royce} from EP.{G. Eric Platford - Chief Quality Engineer} c. to CJ. c. to PN.{Mr Northey} c. to Hm{Capt. W. Hallam - Head Repairs}^c c. to Bt.{Capt. J. S. Burt - Engineer} c. to Hs.{Lord Ernest Hives - Chair} EP{G. Eric Platford - Chief Quality Engineer}1/F27.4.21. X.3427 - RE. CHANGING GEAR - ADJUSTMENT OF CLUTCH BRAKES. X.3339 With reference to your R16/G25.4.21, we have always worked on the principle of having the clutch brake so adjusted that the clutch does not stop too quickly, and our instructions for this routine of adjustment and inspection are that "with the engine running at normal slow speeds and the car standing, the clutch ceases to revolve when depressed fully, in two or three seconds." This adjustment, how it is obtained, and the advantage of it, is also described in our Instruction Book. On our early post-war cars we felt that the range of adjustment on the springs was not sufficient to obtain this and a lower rating of spring was obtained. The adjustment and action of this brake, however, is very much affected by the lubrication of the clutch, more so now with our present oil retaining clutch, as it will contain a large quantity of oil which is certainly very effective so far as the correct action of the clutch is concerned, but certainly causes a drag when disengaged. This point is also brought up in our instructions re attention to the clutch pad. We still find that in most of the complaints we have of faulty changing gear due to the faulty adjustment of this clutch brake, the driver has not taken eu into consideration the condition of the clutch as regards lubrication when making the adjustment. Although there are a few customers who insist on the clutch being adjusted to stop quickly, they are rather exceptional, and we certainly have found that the disadvantage of such adjustment is so great in the hands of the ordinary driver that a free running clutch is much to be preferred to one which stops quickly, and the advantage of this adjustment is clearly demonstrated in our drivers' Demonstration Class. We do not recommend the use of thick oil for the gear box, and although there are various grades of thinkness of Price's amber gear oil, the type we recommend is the thinnest. We have experienced trouble with the viscosity varying, but this we have taken up with the makers and feel we are now correct contd. | ||