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).
10,000-mile bench ignition contact point experiments comparing Iridio-Platinum and Tungsten materials.
| Identifier | ExFiles\Box 35\6\ scan 278 | |
| Date | 19th May 1927 | |
| -3- 10,000 MILE BENCH IGNITION CONTACT POINT EXPERIMENTS. Contact point material. | Conditions | Iridio-Platinum (pt). | Tungsten (Tn.B.). | |---|---|---| | Previous Std. coil Otherwise standard. Dist. run reverse direction to normal. | Remarks. 16P | Remarks. Finished 16.5.27. Condition good. Screw point slightly oxidized. Trimmed once at 7000 miles. 16T | | Previous std. coil; otherwise std. Dist. run at twice normal speed, i.e. 1400 r.p.m. | Finished 14.2.27. Sharp pip trimmed at 5000 miles to obtain consistent sparking. Pip had penetrated to steel on screw. Large proportion of screw pt. transferred to lever pt. Pts. clean & bright. 17P | Finished 14.2.27. Screw point oxidized slightly otherwise condition good. No appreciable wear and no misfiring. 17T | | Previous std. coil; otherwise std. Dist. run at half normal speed, i.e. 350 rpm. | Finished 28.3.27. Trimmed at 5600 miles for regular sparking, also at 9600 mls. Condition V.{VIENNA} fair. Slightly worse than normal. 17AP | Finished 28.3.27. Trimmed at 8000 miles slightly, but misfiring later attributed to coil. Condition fairly good. 17AT | | Previous std. coil; otherwise std. Remy dist. | Finished 14.12.26. Platinum fitted to Remy points. Condition good, surfaces clean and fairly even. 18P | | | USA Bosch dist. coil and condenser. | 19P | Finished 16.5.27. Condition good. Lever point slightly oxidized. No trimming required. 19T | 19.5.27. | ||