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).
Performance issues and criticisms of carburettors, oil filters, and engine components.
| Identifier | ExFiles\Box 91\4\ scan0255 | |
| Date | 15th September 1935 guessed | |
| ( 2 ) CARBURETTERS. [Handwritten note in left margin: Swell] Engine failed to start when hot due to evaporation of petrol in the float chambers escaping via the balancing pipes into the Air Silencer intake. The result being, too strong a mixture was drawn into the Engine. This was cured by uncoupling the balance pipes from the Air Silencer, leaving the gas to escape into the bonnet. Loss of high speed and acceleration during the hot weather was due to the air intakes drawing the hot air from inside the Bonnet. Taking the intakes to the outside of the bonnet gave a smoother Engine, snappier acceleration, and increased maximum speed. Without the cold air intakes the four Carburetters are not satisfactory. On cold mornings the result was the reverse. Removal of the Petrol Filter from under the Bonnet, cured 90% of the trouble of petrol supply failure. The Engine ran remarkably smooth from 50 M.P.H. upwards. Under favourable conditions 90 M.P.H. was reached. [Handwritten note in left margin: LS] The rubber mounting gave no trouble, examination however shows that the rubber on the O.S. has been cut deeply by being continually compressed over the steel washer. The N.S. rubber was hard and brittle on the outside surface, having been affected by the heat of the Exhaust. OIL FILTERS. [Handwritten note in left margin: Swell] The Teclemit Filters element for the hydraulic tappets became choked after approximately 10,000 miles, and very little oil was getting through to feed the tappets. It did not appear to be effective in stopping sludge from going through, as trouble was experienced with the oil hoses feeding the tappets becoming choked. The main Filter was washed and scraped as it was suspected to be lowering the main supply. E N G I N E Criticisms. To drain the Engine oil it is necessary to first press down the locking plunger before the tap can be operated. This plunger is at times compressed with difficulty. A much lighter spring could be used. Oil Filler. Although the mouth of the filler has been enlarged, the pipe itself is too small to take oil freely. One should be able to turn a tin of oil upside down in the mouth, and leave it until it is empty. This is not possible owing to the restriction. The hinged filler cap as fitted on the Bentley is far superior to the present screw cap. | ||