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).
Ignition coil temperature tests under hot summer conditions.
| Identifier | ExFiles\Box 164\5\ img395 | |
| Date | 26th August 1938 | |
| 6017. To By.{R.W. Bailey - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to By/RD. c. to RM{William Robotham - Chief Engineer}/Wym.{G. Harold Whyman - Experimental Manager} Rm{William Robotham - Chief Engineer}/RC.{R. Childs}8/JH.26.8.38. re coil temperature tests. The recent spell of hot weather has proved to us that the Delco-Remy coil, when subjected to hot underbonnet temperatures, coupled with high voltage conditions due to a fully charged accumulator, becomes too hot and because of this, causes misfires on 'pick-up' after a prolonged period of running. In order to ascertain the coil temperatures when subjected to periods of running under summer conditions, road tests have been carried out on 24.C.VI. The results of these tests point to the following conclusions :- (1) The Delco-Remy coil in its present form, becomes too hot when subjected to summer conditions, and is not suitable for production. (2) The use of heat insulating washers is detrimental with respect to the cooling of the coil and should not be used on production. (3) A saving of approx. 20°C. may be obtained on a metal cased coil, by fixing its brackets to the frame instead of the existing position on the crankcase. Mounted in this way the Delco-Remy did not misfire, but its primary winding is still too hot. Under the worst condition this was found to be in the region of 160°C. (4) The 'IN3' coil, in a metal case, is, like the Delco, too hot under adverse conditions. The coil is built on the lines of the Delco but has a gauge thicker primary. A coil with more turns of still thicker gauge on the primary winding should be tried. (5) The R.R. 20,000 turn coil (D.76973) gives a good performance under all conditions. We have, however had failures on the experimental cars. This coil should be tried in a metal case. | ||