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).
Sparking over in the battery ignition distributor head on a 20 HP chassis.
| Identifier | WestWitteringFiles\K\September1923\ Scan50 | |
| Date | 18th September 1923 | |
| R.R. 493 (40 H) (SL 42 12-7-23). J.H. D.{John DeLooze - Company Secretary} EXPERIMENTAL REPORT. COPIES TO: R.CJ. BJ. WOR.{Arthur Wormald - General Works Manager} By.{R.W. Bailey - Chief Engineer} E.{Mr Elliott - Chief Engineer} Da.{Bernard Day - Chassis Design} EP.{G. Eric Platford - Chief Quality Engineer} PN.{Mr Northey} OY. Mr. Brock. Expl. No. 4357. REF. EFC2/T18.9.23. OBJECT OF TEST. To determine if, in any circumstances of running on 20 H.P. chassis, sparking over occurs in the battery ignition distributor head. TESTER. EFC. and CAP. CONDITIONS. The conditions most likely to cause sparking over in the distributor are retarded spark, weak mixture, and full throttle, either for acceleration or for running chassis under brake load or up a hill. These were the conditions under which tests were made. As reported in our EFC1/T14.9.23 a special distributor head with mica windows was utilised and an observer was stationed on the footboard of the car to observe the action of the distributor through these windows, the bonnet being lifted. SUMMARY OF TEST. It was found possible under these extreme conditions to produce a very occasional spark over in the distributor. For instance, in running up a hill a quarter of a mile long, and of such a gradient as to allow the car just only to climb on top gear, about half a dozen spark-overs at the most were observed in the distributor, during the run up, this being, it will be understood, with retarded spark and the weakest possible mixture for consistent running. In view of the extremity of the circumstances and the comparative rarity of spark-overs, it is not considered that the limitations of the distributor seriously affect the performance of the ignition. It is also clear from this and our previous report, that the worst condition of firing in the sparking plug corresponds almost exactly to a spark gap in air on the bench of 6.5 mm. Ignition coils are now being tested to be capable of regularly firing six gaps in air, of this amount, when operating from an 8-volt battery. EFC. | ||