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).
Results of a series of tests on tungsten points for contact breakers.
| Identifier | WestWitteringFiles\Q\December1926-January1927\ 75 | |
| Date | 18th September 1926 guessed | |
| -2- Contd. Tests on Tungsten Points. No.2. Conditions - RR. previous standard + except for the tungsten points. These worked for 9500 miles satisfactorily then failed, owing to the lever point working loose. Condition previous to failure very fair, but surface pitting and pip formed on lever. A sample labelled 2C is a contact breaker lever and point having run for 9447 miles under similar conditions on expl. chassis 44-PK. No misfiring was experienced and the condition was reasonably good. No.3. Tungsten points on Delco-Remy contact breaker and distributor. Conditions otherwise RR. previous standard.+ Condition very good. Absence of pip on lever and surface pitting. These points have been removed from their lever and are contained in an independent envelope labelled 3 (red). No.4. Conditions - RR. present standard, but with tungsten points. Points pitted slightly and oxidised on surface. No misfiring. Condition fair, but not like those run on Delco-Remy. (Nos.4, 6 etc.). No.6. Tungsten points on Delco-Remy contact breaker and distributor, but otherwise RR. present standard. Condition good, but small pip formed on lever; absence of pitting. No.8. Conditions - RR. contact breaker, finer primary coil, double ballast resistance. Condition of points fair. Slight projection of metal on lever point, with corresponding cavity on screw point. Occasional misfiring. No.10T. Conditions as 10P above for platinum, with altered position of contact points in relation to cam, but this time for tungsten points. Lever point good; screw point oxidised. Fairly even contact. Point filed off after 7,000 miles. No misfiring, and this would appear to be the best tungsten point result obtained on RR. contact breaker, just as 10P would appear to be the best result experimentally obtained for platinum points on the RR. contact breaker. Contd. | ||