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).
Investigating the blackening of EAC battery ignition contact points due to oil vapour.
| Identifier | WestWitteringFiles\N\July1925-September1925\ Scan42 | |
| Date | 12th June 1925 | |
| R.R. 493A (50 H) (D.D. 31, 12-6-25) J.H.D. EXPERIMENTAL REPORT. Expl. No. 8680 REF: HPC/TDC.T.25. To R.{Sir Henry Royce} From HPC. c. CE. E.{Mr Elliott - Chief Engineer} c. By.{R.W. Bailey - Chief Engineer} By/RD. EAC. BATTERY IGNITION. X8680 X4652 It is now practically proved that the blackening effect on the ignition contact points which has sometimes occurred on some of the new EAC. chassis is due to the influx of oil vapour through the ball bearing. Utilising a distributor head cut away to make the space in which the rotor works freely open to the air, it has been noticed on a test engine which, with the standard distributor head was bad for blackening of the points, that a big efflux of vapour took place which was largely stopped by removing the crankcase vent cap. The condition varies on different engines and on several EAC. engines the performance of the platinum points is no worse than on the 20 HP. upon which this particular blackening effect has not so far been known by us to occur. In this connection the following report from one of Mr. Hives' testers is of interest :- "We have noticed that the engine we are at present running (No.10 EAC.Special) has considerable blow-past the pistons. With the oil hot and the filler cap removed oil fumes escape freely but with the filler cap in position these fumes pass up into the battery distributor cover and cause the plat.points to burn and pit badly. Perhaps HPC. would be interested in this matter. ACL." from which it will be gathered that this tester is of the opinion that the burning of the contact points is associated with the bad blow-back past the pistons. Contd. | ||