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).
Troubles with Bentley petrol pumps, including vapour lock and carburation issues.
| Identifier | ExFiles\Box 31\5\ Scan094 | |
| Date | 3rd August 1933 | |
| X148f To E.{Mr Elliott - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}13/KT.3.8.33. X2677 BENTLEY PETROL PUMPS. GWH.{George W. Hancock - Head Chateauroux} still continues to have trouble with the petrol system, having the standard arrangement of petrol pipes on his car in France, in spite of the fact that we cannot reproduce his condition over here. Naturally he runs faster, and the French petrol is different from ours. The trouble is not due to the petrol pump being below standard, because we sent out to him another pump which did not eliminate the trouble. He has re-arranged the pipe lines and seems to be almost free from the vapour lock trouble for the time being. We have had certain other troubles in connection with the mechanical petrol pumps most of which have been largely overcome. These troubles were enumerated in our Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}7/KT.24.8.32. We have recently, however, experienced another difficulty, and that is, the carburation is susceptible to the variation in head, which is a feature of the mechanical pump. The mechanical pump delivers petrol to the chamber at about 4 lbs/sq.in. when the car is idling in order to ensure that it will deliver sufficient to supply the engine at maximum speed. This high pressure definitely affects the idling setting of the carburetter. We attach a curve, Rm.{William Robotham - Chief Engineer}B.15, which shows the result of raising the head on the carburetter float chamber. In each case the needle was re-set for idling, the result being that the consumption varied over the whole range as shown. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||