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).
The testing of irido-platinum contact points, detailing wear, misfiring, and rusting issues.
| Identifier | WestWitteringFiles\G\September1921\ Scan57 | |
| Date | 9th September 1921 | |
| R.R. 285A (100 T) (S.H. 159, 11-8-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2800 EFC. AB.22. 9th Sept. 1921 X.1818 -X.3656. IRIDO-PLATINUM CONTACT POINTS. (IPE-IPC) These sets, from Messrs. Reynolds, have the points welded on steel studs which are riveted in position in the usual way. The first set was run normally for about 80 hours, after which the distributor was sealed against air for the purpose of testing platinum sparking points in an unventilated distributor. After a further 120 hours, misfiring occurred and the blade contact was found to have become concave and the screw-point convex; A black patch on both points suggested the presence of impurities in the metal. Very little sparking occurred during the run. The second set was now fitted, and soon settled down to almost sparkless operation, the distributor being still unventilated. After 350 hours, the blade-point was badly concaved and the screw-point convexed, though there was no sign of any impurity. The cam casing and breaker mechanism, however, was smothered in iron rust, apparently from the rocker rollers whose pivots had worn away very badly and raised the make ratio to .7 from .5. This rusting always takes place to some extent and may be connected with current impulses which take place Contd. | ||