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).
Gearbox noise issues and component swapping on chassis B.12.AW, the Paris Trials Car.
| Identifier | ExFiles\Box 146\5\ scan0331 | |
| Date | 23th April 1940 | |
| FJH{Fred J. Hardy - Chief Dev. Engineer} please reply - attach to other memo 126 S To Bentley Motors Ltd. Derby............... Rm.{William Robotham - Chief Engineer} Levallois Sr/VA3/ET.23.4.40 Re: CHASSIS B.12.AW - PARIS TRIALS CAR. We confirm having telephoned to you this morning concerning Bentley V gear box troubles. The position at present is as follows: We removed the gearbox from chassis B.14.AW and fitted it to the above car. We found upon test that the gearbox of B.14.AW was more noisy (rattles and knocks on the overdrive and the 3rd gear, but less pronounced on 3rd than on the overdrive) than the one removed. We then removed the gearbox from B.10.AW and fitted it to B.12.AW. This box is not so noisy as the one removed from B.14.AW but it is difficult to change from top to 3rd without making a noise (crashing). B.12.AW. We have dismantled the original gearbox of this car and find that the side shaft has about .015 end play and to take up this play we shall need a thicker bronze thrust washer, as fitted to the front end of the side shaft. The existing washer is .104" thick (diameter 2 5/16"). We shall therefore require a washer .119" thick. Providing they are available, we should like you to arrange to have sent to us a set of bronze washers of various thicknesses, as fitted to the front and rear end of the side shaft. As Sr. wants us to refit this box to his car, we shall be glad if you will kindly arrange for the material to be sent to us as quickly as possible and by Mail Express. B.14.AW. The gearbox of this car is the worst of the three re noise. Before removing it from B.12.AW, we put the car on our ramp, removed the side plate from the box and it was observed that, when the overdrive was put into operation, there was a bad rattle from the bronze lined cones fitted to the 1st and 3rd motion shaft, especially the one towards the front end of the box wobbled and joggled about rather badly. The noise, however, could be damped out from each cone by applying pressure to the outer diameter of the cone with pieces of wood. Of course, as there was not much oil in the box when carrying out this operation, it may be that the noise coming from the cones and their movement were amplified. | ||