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).
Issues with the rocker cover, radiator, ignition, and carburettors.
| Identifier | Morton\M18\ img035 | |
| Date | 31th July 1935 guessed | |
| ( 7 ) There is too much oil in the rocker cover casing. The angle of the cylinder head causes a well of oil, which reaches above the joint cover, while the engine is running. It will have to be more efficiently drained, as it not only submerges the valve springs, but leaks out of the joint. A considerable amount of this oil is sucked out by the breather when the air silencer is saturated. The carburetter air cylinders have been found with a quantity of oil in. The intakes of the Carburetters were full of oil when dismantled. RADIATOR. The Radiator mounting is satisfactory. The water level (half an inch in header tank) was maintained when no trouble with water boiling occurred. The two front wing stays which were held to the Radiator shell by set screws, were continually working loose. It was not thought possible to use studs & nuts because of clearance in fitting. By a slight alteration to the inner bottom flanges of the stays, we have been able to fit studs and use a full nut and spring washer. The two wing stays have remained firm with this method. DISTRIBUTORS FOR IGNITION. We would like to criticise the Cams of the distribution and the drive. With the amount of backlash in the drive, timing of the contacts is very uncertain, the lag has to be allowed for. It is very easy to get 10° advance or retard of the Ignition. Another disadvantage is the cam being on the small size, brings the make and break of A & B side very close together. It is easy to get a mis-reading of which set of contact points are making or breaking. A slightly larger cam would increase the time limit of breaking of the two contacts (checking timing electrically). We are of the opinion that the two switches A Block & B Block will give rise to complaints when actually there would not be sufficient cause. In this respect we have found that A or B singly were misfiring, but when both ignitions were in use there was no misfires. On other occasions for no apparent reason, the speed of the Car, would be slower when running on B or A singly. The two firing together, normal speed was obtained. One plug not firing would not materially effect the running of the Car, and most probably would begin to fire again, but the Owner having found one plug out would not be satisfied, until it was made right. CARBURETTERS. The Carburation has been affected by the heat of the Engine. The fitting of the carburetters in the VEE, and the petrol pipe lying on top of the tappet cover case, has caused a very strong mixture to be drawn into the Engine, when starting, after the Engine has been stood for over ten minutes. The heat from under the bonnet & the Engine has been absorbed by the Carburetters. Taking cool air to the Carburetters does not over-come this trouble. We have since obtained good slow running. | ||