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).
6000-mile performance report on Chassis 12-EX, focusing on the magneto, battery ignition, and ignition governor.
| Identifier | ExFiles\Box 40\2\ Scan128 | |
| Date | 19th August 1926 | |
| X8793 Extract from GWH{George W. Hancock - Head Chateauroux}1/RP19.8.26. REPORT ON CHASSIS 12-EX. EAC.VIII. AFTER 6000 MILES X.7940. Magneto & Drive. X.8793. Lucas magneto ERS-51A. Modified Hardy fabric coupling to E.74906 to L.O.P. E.73297. The drive has remained in good condition. The magneto is quiet and controls are free from pulsation. The We are not satisfied however with the magneto. The following points will have to be brought to a better standard before it is suitable for cars. The magneto failed altogether at a mileage of 1538 due to its contact breaker sizing in its bearing. Since then it has been missing fire at high speed. At 3000 miles the earthing brush behind contact breaker was found broken, the distributor was burned black on three alternative segments; the brush showing wear. At 6000 miles it became necessary to change the H.T. carbon brush. This had worn down .125” leaving a very little pressure on the segments. Its appearance shews it to have been burning. We also get a difference of .005" between the contact points on the opposite breaks which is a cause of poor slow running. The segments of the distributor require cleaning and polishing every 500 miles. We are sending the worn carbon brush for Mr. Clark's inspection. It would be interesting to know whether the spring pressure is lighter than in the Watford. It appears to be so. Battery Ignition. X.8680. GP4 coil with finer primary winding to L.O.P. D.71008. Contact breaker fitted with bone grey fibre rubbing block in accordance with EFC2/T9.4.26. Stainless steel sparking points and rotor D.71009-10 EFC3/T13.4.26. otherwise to L.O.P. D.70793. Condenser to L.O.P. D.70936. Ballast resistance to L.O.P. D.70843. We have had no trouble with battery ignition. The contact points are still making good contact. There has been a slight pitting of the points taking place. At 6000 miles the break had increased .006” through wear of the fibre block and contact breaker points. The stainless steel sparking points are in good condition. Condenser connections are in good condition. Ignition governor. X.7685. Improved oil relay piston using metal packing rings to Lec.2242.2244. otherwise to L.O.P. E.74694. This has functioned quite satisfactory and we consider that this arrangement combined with the ignition timing is a great improvement. We have not dismantled this as there has been no need to do so. | ||