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).
Engine fuel distribution issues and experiments to improve carburettor performance.
| Identifier | ExFiles\Box 85\4\ scan0013 | |
| Date | 7th February 1933 | |
| X208. FILES. 7.2.33. BENSPORT J.I. Comp. Ratio. 6.3 : 1. E.59139 (113 1/2o) Camshaft. 2 - 1.375 S.U. Carbs. on cast alum pipes, between 2 & 3 and 4 & 5 cyls. DISTRIBUTION. With perfectly balanced pipe, the centre cylinders are weak, while the outside cylinders are rich. By reducing the overhang of the buffet ends past the outer ports, distribution was considerably improved, though M.E.P. was still lost at low speeds, due to gas surging from one end of the pipe to the other. Increased heat improved this, but little was gained. As an extreme comparison the centre of the pipe was completely blanked, and each carburetter separately tuned to give correct mixture. This condition gave good distribution, and an increase in power at middle and low speeds due to ramming. But blow back and very uneven running at high speeds with considerable loss of power resulted. Also pulsation effect caused the pistons to oscillate badly at low speeds. Varying sizes of restriction hole, between the two halves of the pipe have been tried, and it was proved that as the diameter of the hole was increased, as the centre cylinders became weaker and outside cylinders richer. But the front cylinders were affected most by this experiment, and it might be assumed that although good distribution is given with .500 restriction, the position of the carbs. is not entirely suitable to the front end of the engine. This is supported by the fact that with a blank in the centre, uneven running is confined to the front cylinder only. Hs{Lord Ernest Hives - Chair}/C.T.Salt. | ||