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 the performance of various electrical and engine components.
| Identifier | ExFiles\Box 83\2\ scan0304 | |
| Date | 13th March 1938 | |
| ( 10 ) Parts. Result of Test. Lucas Combined Regulator and cut-out. 19,320 miles. Maintained good control of battery charge. Initial charge at start of running considerably higher than standard. No trouble experienced at any time. New Lucas Coil (sent out from Works Rm{William Robotham - Chief Engineer}/RC.{R. Childs}I/JH.1.2.38). 6,433 miles. No trouble experienced. Cold starting and slow running good. Water Temperature Thermometer at front of cylinder head. Whilst the instrument read 1°-2° lower in this position, the needle was inclined to fluctuate 3°-4° above its normal temperature reading of 81°c. This does not occur if a thermometer with a slower response is used. A more dead-beat instrument has been called for. K.L.G. FL.30 X. Sparking Plugs. (Single point) (Standard FLB.30 X. have larger barrels). Short barrels bring terminals too close to induction pipe flanges allowing external sparking to occur under certain conditions. Otherwise satisfactory. Rate of wear .010" in 5,000 miles as previously noted on Bentleys on 15,000 miles test. Lodge Sintox Plugs. Type 640 & 641. (Three point). Run 3,190 miles with satisfactory results. Rate of wear same as K.L.G. .006" in 3,000 miles. More difficult to adjust than K.L.G. The 641 type are preferable to the 640 for Bentley, as they have longer barrels which facilitate fitting. The 641 were also slightly better for wear than the 640 | ||