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).
Investigation into petrol supply failures on the Phantom model caused by air locks from fuel gassing and the subsequent solution.
| Identifier | ExFiles\Box 44\1\ Scan257 | |
| Date | 16th November 1928 | |
| Hs{Lord Ernest Hives - Chair}/GWHL/LG16.11.28. PHANTOM - FAILURE OF PETROL SUPPLY. We have, since fitting the Zenith and Enot's petrol filters in conjunction with the cast dash, had failures of the petrol supply at varying speeds. We found the failures occurred when a different petrol was being used (i.e. a better quality) than our Shell Mex. In investigating the cause we find that the primary trouble is due to the autovac and filter being fitted on the exhaust side of the engine, and with the fitting of the cast dash, the whole of the autovac is under the bonnet whereas previously there has been half the autovac under the scuttle. The failures have also been increased by the fitting of the metal cover to the filter. The heat that the whole autovac now receives combined with the feed pipe to the filter is such that the petrol is gasing very freely. We find that this is to such an extent that the filter becomes filled with gas and causes an air lock. We have been able to overcome this by lagging the whole of the autovac and the petrol feed pipes, but as this looks objectionable we carried out further investigations and have been successful by fitting an air release to the feed side of the filter. To do this we drilled the top of the filter and fitted a .187" pipe which is then led back to the top of the autovac tank. We found that this released the gas sufficiently to prevent an air lock forming and under extreme conditions it has functioned perfectly. contd :- | ||