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).
Component performance and failures including pistons, valve springs, carburetter, and oil pump after mileage testing.
| Identifier | ExFiles\Box 82\5\ scan0154 | |
| Date | 2nd June 1937 guessed | |
| ( 3 ) when stripped after returning, the pistons were found to be cracked in several places. Oil consumption was below 800 mpg. when the car was driven hard. With more gentle driving, 1.400 m.p.g. and over was obtained. There was a steady improvement right up to the end of the mileage. Castrol "XL" was used. N° 6 VALVE spring (Exhaust, No 3 cylinder) EB.3256 broke at 3.322 miles. It was replaced by a standard spring. No other trouble was experienced with the valves and fittings and they were not removed during the mileage. The maximum total tappet clearance lost by any valve during the 15.000 miles was .005". The water temperature fluctuated between 74°c and 82°c indicating faults in the water passages. The thermostatic control of the water flow in conjunction with fixed shutters was good, and allowed for quicker warming up from cold than standard Bentley which is a very useful feature particularly for town work and much appreciated by Sr. in Paris. CARBURETTER. LOP. EB.2705. Irregular slow running was experienced and found to be due to a punctured float in the rear carburetter. The soldered joint round one end of the centre tube had cracked. OIL PUMP. LOP. EB.2216. EB.2133/4 Driver Gears 22° angle. Increased capacity Helical Gears. The oil pump was very noisy for several minutes starting from cold. Both Bentleys in France with these oil pumps were bad in this respect. Oil pressure was between 25 and 30 lbs/sq" at 70 m.p.h. up to 95°c oil temperature. With a further rise to 115°c, 23 lbs/sq" was obtained. The pressure obtainable at full speed with oil temperature at 120°c, the normal maximum was 20-23 lbs/sq". the highest reached under extreme conditions was 135°c. and oil pressure at maximum speed fell to 18 lbs/sq". [Handwritten note on the left margin] Dodd. where have our tests got to Rm{William Robotham - Chief Engineer} | ||