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).
Specification and test report for a Zenith Carburetter, Type 48VI-2.
| Identifier | ExFiles\Box 122\1\ scan0189 | |
| Date | 5th June 1935 | |
| To Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c.c. to Hs{Lord Ernest Hives - Chair}/CTB. X1034 Hs{Lord Ernest Hives - Chair}/GR.{George Ratcliffe}7/KW.5.6.35. 18-G-IV. Zenith Carburetter; Type 48VI-2. Specification as received from test bed :- Choke 36 Main Jet 165 Comp.jet 150 Slow running 70 Cap. tube No. 1. Economy - nil. Pump 13 mm. Spring 600 grms. Jet 70 Leak 50 Ventilation over capacity tube 4.0 mm. Fitted to 18-G-IV with 6-port manifold, large capacity, central floor water heated. Acceleration was very poor up to 25 M.P.H., carburation being weak with flat spots at 28/33/35 m.p.h. Above 40 m.p.h. carburation appears O.K. Slow running fairly good at 3 m.p.h., but not quite so even as Stromberg. Running idle was uneven and showed up worse than Stromberg. Slow speed acceleration, part and full throttle was very poor, the lag between idling and main feed being very prominent at 5 to 10 m.p.h. It was found that when fitting the carb., the flange had a very bad air leak of .004". This was faced up and the necessary adjustment made to the low speed air bleed. This alteration was the only one from the original setting on the test bed. Consumption checked:- 13.3 m.p.g./46 m.p.h./70 miles. Hs{Lord Ernest Hives - Chair}/C.Ratcliffe. | ||