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).
Diagnosis of blackened distributor points, concluding the cause is oil vapour, not an electrical fault.
| Identifier | ExFiles\Box 70\3\ scan0163 | |
| Date | 1st June 1926 | |
| Contd. -2- EFC1/T1.6.26. recognised by the points appearing dirty and usually badly blackened all over their surfaces. This effect does not take place on the bench where oil vapour cannot be present. Thus you will see that the worst part of the problem is not an electrical one, but consists of the mechanical exclusion of oil vapour from the distributor head. Steps have been taken in recent designs to overcome this, and improvements are by this time already in production. At the same time, electrically we now have ignition coils of higher inductance, taking a smaller current; this will help the platinum points appreciably, in the absence of oil, but will not materially reduce the blackening when oil vapour is present. It will probably be found that in the distributor head on Mr. Sidney's car there is an oil film on everything, indicating the presence of oil vapour when running. Contd. | ||