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 S.U. Carburetter Co. Ltd. concerning variables when tuning a thermostatic carburetter.
| Identifier | ExFiles\Box 121\4\ scan0217 | |
| Date | 8th October 1938 | |
| TELEPHONE: BIRMINGHAM EAST 1171. TELEGRAMS: FLEXCARBUR, BIRMINGHAM. THE S.U. CARBURETTER CO. LTD. PROPRIETORS - MORRIS MOTORS LTD. VISCOUNT NUFFIELD CHAIRMAN OLIVER BODEN, O.B.E. VICE-CHAIRMAN T.C. SKINNER, M.I.A.E. MANAGING DIRECTOR ADDERLEY PARK, BIRMINGHAM, 8. YOUR REF: OUR REF: BC/ER 8th October 1938. Messrs. Rolls-Royce Ltd., D E R B Y. Dear Sirs, For the attention of Mr. Salt. Car Experimental Dept. Replying to your letter of the 7th inst., concerning variables when tuning the thermostatic carburetter. Relating to your present 4½-Litre layout, it is fairly definite that you will only use the "middle" taper, of the three variable tapers on the accelerator needle - that of .008" to the one eight of an inch. We will, if you like, make up (they are not stocked) the other two tapers, but as previously mentioned on the present engine they would not warrant even the fitting time. The spring variable has already been settled by conversation and letter. Regarding the suction disc, the diameter can be varied and the best way of dealing with this will be to have half a dozen stock .455" diameter discs (complete with needle) and turn off the outside diameter to any smaller specified size. Probably the .435" diameter disc would suit your job, as mentioned in previous correspondence. We would advise varying in "steps" of .010" on this diameter. The suction disc may also be varied in its position (seated on) on the needle - the standard position gives 5/16" needle travel - as a maximum this figure can be increased to ⅜" or reduced to a minimum of 3/16". -1- | ||