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 detailing troubleshooting of acceleration failures and recommendations for improving the petrol delivery system.
| Identifier | ExFiles\Box 91\2\ scan0082 | |
| Date | 7th July 1937 guessed | |
| ( 2 ) Accelerated to 60 MPH. Partial failure with gradual acceleration to 80 MPH. 60 seconds to complete recovery. Further 12 mins. running, Air 27°c, U.B. Air 60°c 10 mins. halt. Air 27°c, U.B. Air 70°c, Petrol in Tank 37°c. Delivery pipe disconnected from pump in frame, pressure release noted when union was loosened off. Engine then switched on. Pump worked for 15 seconds before giving full delivery. During this time spasmodic splashes of petrol only delivered. Pipe connected up again and car accelerated. Again hesitated at 60 MPH. Delivery intermittent for 1 min. 15 seconds. Bonnet was then removed, and car run 12 mins. Air 28°c, Air under carburetter 56°c. 10 minutes halt - Air 28°c, Air under carburetter, 46°c - Petrol in tank 37°c. No failure on acceleration. Further 12 mins. running, bonnet still removed, Air 29°c, Air under Carb. 56°c - 10 minutes halt Air 29°c, Air under Carb. 45°c Petrol in tank 37°c. No failures on acceleration. Finally cutaway covers fitted to the frame pump and the floorboard removed. The bonnet was again fitted and the failure reproduced. It was verified that the pump was working during the failure. The weather has now become cooler and running has been resumed with the parallel pump scheme working as fitted up at Derby. We can think of no single thing we can do to effect a cure but would recommend a combination of all details known to give an improvement, however slight. 1) Petrol pipe outside frame wherever possible. 2) Petrol filter outside frame. 3) Pipe to carburetter outside Vee. 4) Bonnet doors open possibly facing forwards. 5) Non-return valve in petrol tank vent or restriction hole. (This car has an open vent hole on the filler spout, no pipe being fitted. It was noted that no pressure is built up in the tank as was the case with 35-EX. which had a long vent pipe which gave restriction.) | ||