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).
Test report on car 33-MX after modifications, detailing issues with over-oiling and carburettor flooding.
| Identifier | ExFiles\Box 96\3\ scan0001 | |
| Date | 9th September 1935 | |
| from Mx.{John H Maddocks - Chief Proving Officer} lxd1/T9.9.35. PARIS TRIALS CAR 33-MX.{John H Maddocks - Chief Proving Officer} We have run this car 100 miles after modification as outlined in lxd12/T26.8.35. The fully split pistons have overcome the piston knocks. Although considerable improvement to the overoiling has been effected by fitting white metalled connecting rods and split pistons with slotted scraper rings, there is still too much smoke from the exhaust. We had no trouble with overoiling of sparking plugs. We think the overoiling is due to oil getting past the valve stems. Owing to the cylinder angle the valves are partially submerged in oil, and some scheme is required for draining this excess of oil away. We do not consider that we shall ever be able to rely on the "grummits" to deal with the excess of oil which lies in the cylinder heads. Carburetter flooding. The filter has been fitted to the pipe line near carburetters. During a test run yesterday one of the rear carburetters started to flood violently and we had to return to the Works. We were rather scared about this as the drain pipe led the petrol right on to the hot exhaust pipe. Altered and lengthened drain pipes are being fitted. It is possible that the flooding was due to foreign matter which had got into the valve seating during the fitting of new pipe line to the filter, but we could not find any definite evidence of foreign matter on dismantling. contd- | ||