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).
Modifying Bentley carburettor terminals and the float chamber drainage system to prevent flooding and sparking.
| Identifier | ExFiles\Box 3\6\ 06-page163 | |
| Date | 5th May 1934 guessed | |
| - 3 - replaced by a spring washer and milled nut giving a firm grip on the end of the H.T. conductors, and we should like information confirming, or otherwise that the two Bentley cars in question were equipped with this type of terminal which is standard for K.L.G. plugs at present on the Bentley. An additional reason for cancelling these terminals on the Bentley is that they can get round into such a position as to short the plug to the induction pipe, and thereby create another source of sparking. We now return to the question of petrol emission from the float chamber. It has been Rolls-Royce practice for some time to use completely sealed float chambers ventilated and balanced by a passage way communicating with the air inlet casting, and the 20/25 S.U. type of carburetter about to come into production is arranged in this way. The Bentley S.U. however is practically the standard S.U. production with independent float chamber bolted on having an external balance and ventilated passage communicated to the atmosphere. It was the policy to use the standard S.U. carburetter for the Bentley and all our experimental experience was gained with standard instruments equipped with the standard float chamber mechanism. We do not consider this mechanism a first class job and we have not used it in our own design for the 20/25. To deal with the immediate position regarding flooding we have put in hand a scheme for modifying the existing carburetter by attaching a banjo connection to the vent in the lid{A. J. Lidsey} joined by a pipe to the existing drainage system on each of the carburetters. Float chambers will be thus vented and balanced to the existing drainage pipes the upper end of which is connected to the air inlet and the lower end of which discharges on to the road. This requires testing to see that the carburation is not upset in any way, and we should also be sure that the bottom end of the drainage pipe is not in a position where it is liable to be subject to depression due to a current of air passing across the outlet hole. If, as we anticipate, this scheme turns out to be satisfactory we think that all Bentley cars should be fitted with it. This is a comparatively easy modification to make and should ensure that in the event of heavy flooding the petrol will not be discharged externally but will be dealt with by the drainage pipe and is carried clear of the engine and undershields on to the ground. We also propose to cancel the hand flooders. If we do this and also seal with all possible | ||