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 the performance and wear of aluminium-tin bearings after 110 hours of testing.
| Identifier | ExFiles\Box 116\1\ scan0028 | |
| Date | 12th April 1938 | |
| ALL COMMUNICATIONS TO BE ADDRESSED TO THE FIRM AND NOT INDIVIDUALS TELEGRAMS: DENNIS GUILDFORD TELEPHONE: GUILDFORD 1575 (7 LINES) OUR REF. JM{Mr Morley}/CS. YOUR REF. RM{William Robotham - Chief Engineer}/Mths.{Reg Matthews} 7/AP. 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 DENNIS ESTABLISHED 1895 12th April, 1938. Messrs. Rolls Royce Ltd., DERBY. Dear Sirs, We beg to thank you for your letter of the 5th inst., re aluminium-tin bearings, and have pleasure in advising you that so far the bearings have covered approximately 110 hours running, the majority of which has been under fairly heavy conditions. The average speed has been 1500 r.p.m. when a minimum of 100 lbs per sq. inch b.m.e.p. has been maintained. We are enclosing you a set of photographs of the bearings as they were recently stripped for examination, and you will note that there appears to be a tendency for a "wiping" of the metal immediately under the centre line of the connecting rod. This marking is not very pronounced. You will note also that there is evidence that dirt has entered the bearings, and this we feel sure is due to the design of the big end of the connecting rod which employs setscrews to hold the cap in position. The drilled holes for the top setscrew passes into the oil hole leading from the big end bearing to the gudgeon pin bearing, and under certain conditions it is possible for foreign matter to be pushed through by the set-screw into the drilled hole for the supply of lubricating oil to the little end. We are also forwarding you two prints giving the dimensions of the crankshaft before and after the present series of runs. The engine is now being re-assembled and should not be normally stripped again until about the 23rd instant. We will advise you of any further observations which we make, and if there are any points which you wish us to note specially, please advise us and we will let you have whatever information is possible. We cannot be sure of the exact date when the engine will be next CUSTOMERS' VEHICLES DRIVEN AT OWNER'S RISK ONLY. | ||