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).
Test results and data for modifications to S.U. carburetter float chamber covers on a Bensport petrol pump.
| Identifier | ExFiles\Box 27a\2\ Scan203 | |
| Date | 15th July 1933 | |
| X2677 To E.{Mr Elliott - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/W.Bell. c. to By.{R.W. Bailey - Chief Engineer} Hs{Lord Ernest Hives - Chair}/WB.{Mr Brazier/Mr Bell}8/KT.15.7.33. BENSPORT PETROL PUMP TESTS. X489 Modification to S.U. Carburetter Float Chamber Covers. With the full Bensport suction and delivery systems installed with a standard Bensport pump, the various details of the float chamber covers (2 off) were modified, and the delivery measured after each modification, for comparison with the open pipe delivery. Owing to the variation of the latter, it was deemed preferable to express the results obtained as percentage reduction relative to the open pipe delivery measured prior to each modification, all figures shewn were taken at 2000 r.p.m. | | | Delivery Pts/Hr. | Reduction % | |---|---|---|---| | | | Open Pipe | With Modification | | | 1. | Float Chamber Covers Comp. .125" Needle Valve Seats. | 133 | 112.5 | 15.4 | | 2. | As 1. with six needle valve release holes (same result with four holes) .125 dia. ea. | 133 | 116 | 12.8 | | 3. | Needles removed. | 133 | 120.5 | 9.40 | | 1a. | Float chamber covers comp. .095" needle valve seats - standard. | 133 | 106 | 20.3 | | 2a. | As 1a. with four needle valve release holes .125 dia. each. | 133 | 109 | 18.0 | | 3a. | Needles removed. | 133 | 109 | 18.0 | | 4. | Float chamber covers only - No seats etc. | 133 | 126 | 5.25 | The valve chamber cover was designed with a .187" diameter port between the pipe connecting union, and the needle valve seat, which, coupled with the fact that the direction of flow was suddenly changed - through an angle of 90° - was a possible source of restriction. In addition | ||