Rolls-Royce Archives
         « Prev  Box Series  Next »        

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).
Comparison of the lifespan and performance of different magneto and battery ignition contact points.

Identifier  ExFiles\Box 48\2\  Scan469
Date  2nd February 1927
  
To R. {Sir Henry Royce} from EFC. {E. Fowler Clarke - Electrical Engineer}
c.c. E. {Mr Elliott - Chief Engineer}
c.c. BY. {R.W. Bailey - Chief Engineer} & WOF.

X8796

ANSWERING YOUR COPY.
OF MEMO. TO ROLLS-ROYCE LTD. DA {Bernard Day - Chassis Design}
EXPERIMENTAL ENGINES ON BEHALF
OF
LOW CHIEF INSPECTOR OF ENGINES

EFC {E. Fowler Clarke - Electrical Engineer} 3/LG16. 2.2.27
(218JSQ)

LIFE OF MAGNETO AND BATTERY
IGNITION CONTACT POINTS. X.4652 X.8793/6. (Note: X.4652 and X.8793/6. are crossed out)

We have no experimental evidence to the effect that Lucas magneto contact points last appreciably longer than those of other magnetos, but our evidence is limited to the case of one magneto of this type only. Experiments on later Lucas magnetos received are in abeyance with the exception of one which you have on 7-EX which had done 660 miles at the time you received the car.

Enquiry reveals that the points of Watford E06 magnetos on customers' cars last particularly well - there are very few complaints, though we have had one or two cases apparently of early failure (exact record not kept) on experimental cars.

Current reversal is so helpful on platinum point life that it appears that the life of magneto points can hardly be taken as a criterion of that of B.I. points.

In nearly every clean (free from Oil) case on our own B.I. a pip forms on the lever point and a hollow on the screw point. This effect continues to grow until the platinum pip reaches the iron of the screw point when misfiring begins. Tungsten points do not do this seriously but become oxidised, which sometimes causes missing. On the whole we are now almost coming to the conclusion that tungsten points would be better because the material is not lost or transferred so rapidly and the points can therefore be refaced more often. The impending 10,000 miles test on experimental chassis 10-G3 will provide us with evidence on which to base a decision re. standardisation.

In the meanwhile we are awaiting the new design of contact breaker.

EFC. {E. Fowler Clarke - Electrical Engineer}

[Handwritten notes at bottom left:]
K G Cooq up
Cromwell Olqel up
Engine Up
Yqqless
Issue of Cromwell

[Handwritten notes at bottom right:]
Moyle Olqel up
: Date
: Tabs

[Reversed stamped text at bottom:]
ROLLS-ROYCE ENGINES AND SPARES
CERTIFICATE OF INSPECTION BY V.I.D
CERTIFICATE UP
  
  


Copyright Sustain 2025, All Rights Reserved.    whatever is rightly done, however humble, is noble
An unhandled error has occurred. Reload 🗙