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).
Use of Textolite timing gears for Bentley and 20/25 engines.
| Identifier | ExFiles\Box 136\1\ scan0183 | |
| Date | 28th March 1936 | |
| X1155 To E.{Mr Elliott - Chief Engineer} c. to Wor.{Arthur Wormald - General Works Manager} c. to By.{R.W. Bailey - Chief Engineer} c. to EP.{G. Eric Platford - Chief Quality Engineer} c. to Sft.{Mr Swift} c. to Mx.{John H Maddocks - Chief Proving Officer} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}11/KW.28.3.36. Textolite Timing Gears. It would appear that, having regard to the present programme, we are committed to two or three years output of the existing 25/30 unit which is used both in the Bentley and in the 20/25. Production, Test Dept. and Experimental all agree that the timing gears are one of the most unsatisfactory features of the engine. Production have the utmost difficulty in getting reasonably satisfactory gears and these are frequently criticised on test. This has long been appreciated. Solely with a view to aiding production, we embarked upon a series of experiments with textolite gears, and these satisfactorily completed a high speed continental run, a Standardisation Sheet being signed up 3 months ago. Production are emphatic that with these gears they can save 18/0d. per car and produce a better job. The Test Dept. are emphatic that the 12 sets they have had through their hands were a better job and would overcome the majority of the existing criticisms. The reason we cannot have textolite gears on engines being produced to-day is that we are now using the 20/25 balancing cam fixing. If we revert to the Bentley balancing cam fixing and the small crankcase alteration required to accommodate this, we can have textolite gears. The Bentley cam balancer has been criticised because one sample was found which had worked loose. From our experience, however, we should say that this sample was due to a fitting error, because we have run this design 100,000 miles in France, many more in England, and over 1000 hours high speed test running without ever having encountered trouble. We should therefore recommend that we revert to the Bentley type balancing cam so that textolite gears can be fitted if desired. We say that the 12 sets produced can be examined from time to time, and should give ample evidence as to the success of the experiment in customers' hands. It should be appreciated that we are committed to textolite material on all Ph.III cars now being produced. Technically of course our only interest in the material is that production say they can get a better job for less money, and the Test Dept. agree with them. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||