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).
Tests to diagnose an engine's failure to start, focusing on coil and ballast resistor performance.
| Identifier | ExFiles\Box 6\6\ 06-page385 | |
| Date | 27th November 1937 | |
| To Rm{William Robotham - Chief Engineer}/Wym.{G. Harold Whyman - Experimental Manager} from Rm{William Robotham - Chief Engineer}/W.Brazier. TESTS TO ENQUIRE INTO THE FAILURE TO START 25.G.VI. When the failure occured the engine was fitted with a Delco distributor, glowray wire ballast resistance, 15,000 turn R.R. coil and standard sparking plugs. A 20,000 turn R.R. coil also failed to start the engine until the ballast resistance was short circuited. 1st. TEST. The car was left in the cold chamber all night at 20°F.{Mr Friese} The only change from when the failure occured being a 20,000 turn coil fitted, the idea being to see if we were clear with the proposed production fittings. An almost immediate start was the result. 2nd. TEST. Car left in the chamber all night at 20°F.{Mr Friese} Fitted with 15,000 turn coil and all other fittings as when the engine would not start with R.W. It was found to be impossible to start the engine in this condition. As we had already tested the ballast resistance and found it to be high, we changed to a standard one. The engine would still not start. A 20,000 turn coil was then fitted and a start was obtained immediately. A further test with the previous ballast was not so good, but the engine started. 3rd. TEST. With the failure of the 20,000 turn coil to start when we brought it out to Duffield, in our minds, we ran the engine for two minutes with the ballast resistance shorted. This was sufficient to oxidise the contact points, and with the resistance again in circuit a start could not be made until the points were cleaned. From the results obtained we say the failure to start 25.G.VI was due to an inefficient coil coupled with a ballast resistance higher in value than the one called for on drawing No. D.W.295. | ||