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).
Letter from Dennis Bros Ltd discussing modifications to a centre main bearing for a petrol engine.
| Identifier | ExFiles\Box 116\1\ scan0065 | |
| Date | 9th September 1938 | |
| BY APPOINTMENT HEAD OFFICE AND WORKS DENNIS BROS LTD COMMERCIAL VEHICLE AND FIRE ENGINE MANUFACTURERS GUILDFORD SURREY ENGLAND A B C CODE 5TH EDITION LIEBERS 5 LETTER BENTLEYS MARCONI ALL COMMUNICATIONS TO BE ADDRESSED TO THE FIRM AND NOT TO INDIVIDUALS TELEGRAMS: DENNIS GUILDFORD TELEPHONE GUILDFORD 1575 (7 LINES) OUR REF. JM{Mr Morley}/EMA. YOUR REF. RM{William Robotham - Chief Engineer}/CTS{C. Trot Salt - Carburation}/2/JH. DENNIS ESTABLISHED 1895 [Handwritten]: 1020a 9th September 1938. [Handwritten]: C.T.S. [Handwritten]: See me R Messrs. Rolls Royce Ltd., D E R B Y. Dear Sirs, We beg to thank you for your letter of the 6th inst. referring to the trouble with the centre main bearing of our 100 x 120 4-cylinder "C" Type petrol engine. We have pleasure in forwarding you herewith a further blueprint of the original centre main bearing 34445, together with a print of the later type bearing 35755. You will note that the latter bearing has only one oil hole and that we do not call for a dowel hole in the top half of the bearing. Further, the position of the oil groove has been altered in such a manner as to register with the oil supply hole and at the same time reduce the effective area of the bearing by as small an amount as possible. The reason underlying the use of two holes in the top half of the original bearing 34445 was to enable us to use one bearing as a spare for both our "B" and "C" type engines. In view of the trouble which we have had with the centre main of the latter type engine, we have decided to increase the bearing area as much as possible and this will mean our giving the new bearing a separate part number; this being 35755. Actually this drawing does not show the bearing which we propose to use, but is merely one which has been manufactured to deal with engines which are already out in service, and you will note that we have called for the use of a thinner section of white metal. In answer to your query why the oil groove did not go round the centre of the bearing, we would state that this is due to the fact that commercial vehicle engines are normally run long beyond the stage when they should have been withdrawn [Left margin, vertical text]: CUSTOMERS' VEHICLES DRIVEN AT OWNER'S RISK ONLY. | ||