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).
General notes on the running performance and issues encountered with a vehicle's engine, clutch, and transmission during a mileage test.
| Identifier | ExFiles\Box 83\2\ scan0306 | |
| Date | 13th March 1938 | |
| (I2) GENERAL NOTES ON THE RUNNING. The engine proved very reliable and was not dismantled in anyway during the mileage. There was a slight period noticeable at 3,300 r.p.m. but this became no worse during the running. The power was good and maintained throughout with no appreciable change in the tappet clearances. Both petrol and oil consumptions were better than previous Bentleys on 15,000 miles test. The carburettors were inclined to flood causing poor idling and difficult starting when hot. This was attributed to the leverage on the needle valves being barely sufficient for use with the high pressure petrol pumps. The engine failed altogether on one or two occasions for a short period when travelling on snow, usually preceded by symptoms of weakness. This was first attributed to low under-bonnet temperature with fixed shutters, but this explanation was subsequently discredited. The trouble once occurred under normal conditions. It could not be reproduced by any of the various tests tried, and no reason can be given. It is regarded as an isolated fault, probably peculiar to this car. Bad water leaks developed from the water pump gland, and oil leaks were experienced from the rocker cover joint. It was necessary to renew the dynamo brushes near the end of the mileage as they had worn right down. Knocks were experienced due to the centre bolts of the torque reaction dampers fouling. The holes in the centre plates were enlarged to give more clearance. The thermoid clutch was good for smoothness of engagement, and the light pressure with the pedal servo spring an improvement on standard for traffic work, gear changing, and also for making it easier to fully disengage the clutch before engaging a gear for starting off. The general characteristics of the overdrive gearbox were thoroughly good. The rear axle flange joints were good for freedom from oil leaks. The thick half shafts and strengthened driving dogs contributed to a general improvement in the transmission. | ||