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).
Failures and troubles experienced with Engine II PER N°6 during a 10,000-mile test.
| Identifier | ExFiles\Box 179b\3\ img374 | |
| Date | 25th March 1933 guessed | |
| - 2 - not good, starting at 536 M.P.G. and finishing with 308 M.P.G. Petrol consumption was high, but the carburettor was not final in design and consumption tests carried out will enable better results to be obtained. The following are failures and troubles experienced during the 10,000 miles. ENGINE II PER N°6 The engine retained its power, showing no signs of fatigue during the long sustained runs. Starting up from cold became worse as the mileage increased, several attempts having to be made before the engine continued to fire. depreciation of the petrol pump diaphragms being the probable cause, as they failed completely later. A test with separate gravity tank proved two things: (1) That the erratic starting up was not the fault of the carburettor. (2) That the faulty starting up was due to shortage of Petrol. With the gravity tank fitted the engine started up immediately and continued to run. After fitting new fabrics to the petrol pump although a slightly longer time was taken before the engine fired, no second attempt had to be made. The engine became very dirty with oil leaks from the rocker cover joint, breathers in rocker cover, front of engine & dynamo drive housing. These features are the result of sustained maximum speeds. When the car was not driven above 60 M.P.H. ie. approximately half throttle none of the above oil leaks took place and the engine remained clean. It would appear that at maximum speeds the breathing of the engine case is inadequate. Slow running of the engine was poor throughout the mileage. A slight improvement was made after attention to the carburettor, but poor distribution was the main cause. Detonations became noticeable after a mileage of 4,800. Towards the finish of the mileage the ignition had to be retarded 5 to 6 notches when accelerating from low speeds, to lessen the pronounced detonations. | ||