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).
Fitting of aluminium tin big-end bearings and the introduction of an overdrive gearbox for Bentley.
| Identifier | ExFiles\Box 146\1\ scan0169 | |
| Date | 18th January 1938 | |
| 1245 W/P. Sr. from Rm.{William Robotham - Chief Engineer} Rm{William Robotham - Chief Engineer}2/R.18.1.38. We have to-day telegraphed you as follows:- "ALUMINIUM TIN BIGEND BEARINGS SHOULD BE FITTED "TO P.III AS SOON AS POSSIBLE. THIS MUST NOT "INTERFERE WITH Hs{Lord Ernest Hives - Chair}' TRIP TO THE RIVIERA." In order to avoid big-end failures and to enable you to dispense with the oil cooler, which is an unreliable and expensive fitting, we are trying to standardise these big-end bearings as soon as possible. With this object in view, we want to get as many cars running about with them as possible. We are fairly happy about their durability. Our main concern is whether they can be fitted up both in production and by Depots and where any problem arises about running them in. For this reason we do not particularly want you to put up big mileages; on the other hand, as soon as they are run in we should like you to give them all the hammering you can for a few thousand miles. The idea of this is because you can always produce worse conditions in France than we can in England. Will you, therefore, try and get 3 or 4,000 miles of 100% batting in, within a reasonable period. With regard to my Brother-in-Law's trip to the Riviera, he has now decided to go via Boulogne. I would, therefore, be obliged if you would amend your route and list of suitable eating houses accordingly. You will be glad to hear that it was decided yesterday to introduce the overdrive box on the Bentley, subject to a 15,000 miles' test in France, at the 101st chassis in 'M' Series, which at the present rate of Sales will enable the announcement to be made somewhere about Motor Show time. The car with this box on will be in France next week, and we will ask Waller to give you an early opportunity of trying it. With a 10 x 43 rear axle ratio it gives 106 m.p.h. @ 4,500 revs on the overdrive, and with the present standard rear axle ratio of 10 x 41 it will give 112 m.p.h. @ 4,500 on the overdrive, which should take care of any reduced windage bodies which your customers may demand. Rm.{William Robotham - Chief Engineer} | ||