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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).
Informational leaflet and advertisement for The Bradwell Tester, an engine diagnostic tool.

Identifier  ExFiles\Box 76\3\  scan0160
Date  27th July 1922 guessed
  
HOW TO USE IT. THE BRADWELL TESTER. WHAT IT DOES.

T U R N

THE SMALL ARROW -> opposite RUNNING POSITION ... Tester is out of Action ... This is Position when Driving.
THE SMALL ARROW -> opposite SPARK TESTING ... The Engine Shuts Down ... A good position when leaving Car unattended.
THE LINE MARKED No. 1 CYL. opposite SPARK TESTING ... A bright glow appears in the Tube in Centre of Dial ... This Tests the Spark at the Top of Plug in No. 1 Cylinder.
THE LINE MARKED No. 1 CYL. opposite CYLINDER TESTING ... The Engine runs on No. 1 Cylinder only ... Completes Test of the Plug, also Tests Mechanical Condition of Cylinder, Valves, etc.

Successive Movements of the Dial will Test Nos. 2, 3 and 4 Cylinders and Plugs in Turn.

WHAT THESE TESTS PROVE
Turning the Line No. 1 Cylinder opposite "Spark Testing" makes connection with the top of the plug and the current passes through the vacuum tube instead of the plug, therefore a light in the tube shows that the magneto and connections are right and also that the plug is neither short circuited nor set with the points too close. This is so because the vacuum tube is specially tested to ensure that the current will pass through it in preference to a gap of 10/1000 of an inch at atmosphere pressure. Plug points should be 15/1000 to 20/1000 so if points are too closely set, or "sooted up" there will be no light in the tube.
If the porcelain of plug is cracked there may be a light in the tube, but this defect will be located when testing cylinder.
Turning the line No. 1 Cylinder opposite to "Cylinder Testing" cuts out all other cylinders, and

The Vacuum Tube which produces a vivid Violet Coloured Light.

AND WHY THEY DO SO
the engine running on one cylinder shows that the plug is right and also makes it possible to locate knocking, and, by running other cylinders under similar conditions to test engine compression.
If it is impossible to start the engine the tester will still be useful, for by using the self-starter or swinging the engine the 4 spark testing positions can be tried and should no light appear in the tube it is evident that the trouble is in the magneto, possibly the contact breaker is defective.
A little experience in using will prove our claim that it is "a technical adviser on the dashboard," and that it will quickly locate most of the motorists' troubles which usually take only a short time to put right but such a long time to find.

Obtainable from Garages, Accessory Factors, or from Sole Manufacturer:-
JOSEPH STEER,
41/44 WEAMAN STREET,
BIRMINGHAM.
Phone: Cen'ral 5573. Telegrams: STEER, Birmingham.

4-CYLINDER MODELS.
Type A For Dashboard complete with High Tension Cables £3.3.0 EACH.
Type B For use in Garage. Fitted in Strong Case of Polished Teak £4.4.0 EACH.

6-CYLINDER MODELS.
Type C For Dashboard complete with High Tension Cables £5.5.0 EACH.
Type D For use in Garage. Fitted in Strong Case of Polished Teak £6.6.0 EACH.
  
  


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