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 the cause and cure for engine flooding on the Phantom III model.
| Identifier | ExFiles\Box 93\2\ scan0191 | |
| Date | 15th May 1937 | |
| 308 Lds. C. Mr. By.{R.W. Bailey - Chief Engineer} Rm.{William Robotham - Chief Engineer} RHC.{R. H. Coverley - Production Engineer} Fm/SWH. DA{Bernard Day - Chassis Design}-ISH. Phantom III Flooding. With reference to the above trouble, evidence points to its nature being epidemic, and we, therefore, look for some reason to correspond. We think we have discovered the cause of the trouble, and a cure. In a filter body and floatchamber taken from a test car selected at random from Phantom III chassis that had completed their test we found thin thread like slivers of aluminium which have obviously come from the same source. The lodging of any one of these pieces of metal underneath the float needle in its passage from the filter to the floatchamber would be enough to cause pronounced flooding. The velocity of flow in the vertical part of the petrol pipe leading to the carburetter and in the float needle compartment must be sufficient to carry these thread like pieces of aluminium up the pipe and over the weir for them to be found in quantity in the floatchamber. The filter chamber is closed by a stainless steel plug, and we were able to demonstrate that screwing in this plug released or cut off these needles of aluminium, which latter were then able to pass through the 60 mesh gauze, and so to the carburetter. The 60 mesh gauze is what has always been used in the past for S.U. carburetters and is being used at the present time on Bentley carburetters. On the 25/30 we have a similar filter in 100 mesh gauze which we think is fully capable of stopping these aluminium needles, and we have now made flow meter and engine bed tests which confirm that the fine gauze can be used on Phantom III without loss of power. A report is being issued, and we should like to have Experimental agreement. It is unfortunate that we have the coarser gauze on Phantom III, but this is what is used and is satisfactory with the S.U. carburetter, and was not changed when the | ||