Re: 1937 ignition coil specs
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Forum Ambassador
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Packard didn't give much info on coils other than amp draw. For 37 coils, the current for "idling" which I assume is points open is 1/2 amp and for "stopped" which is probably points closed is 2 1/2 amps. When testing all they used was a go or no go type coil tester so don't have any actual winding specs but approx half the value of a 12v coil doesn't sound too bad.
Have you verified coil voltage as measured to ground and the possibility of shorts? If pos ground, 6v or battery voltage should be at the negative terminal coming from ign switch. If the points are open 6v would also be on the positive coil terminal or at dist. If points are closed pos terminal should be low near 0v or no more than about 3/10 at the terminals. I would verify the points are closing and the positive or dist terminal is making the change. Also check that nothing in the dist is shorted keeping it at a constant 0 or a high resistance problem with the dist ground is not allowing the points to pull the terminal to a full low. Anything higher than 1/2 v with points closed needs to be looked into. When cranking, ideally the supply voltage to coil should not drop much below 5.5 v. If it goes much lower -- say close to 5v -- the spark will be weak and might not reliably jump the plug gap under compression.
Posted on: 2018/5/18 17:29
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Howard
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Re: 1937 ignition coil specs
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Forum Ambassador
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The chances that no spark at the plugs is caused by a bad coil are relatively low. Just to eliminate the cap and rotor, verify that you have spark from the coil. Your most likely culprits, assuming good connections, are a shorted primary feed to the coil from the ignition switch, a failed condenser, or bad/misadjusted points.
A key question, is your ammeter indicating a current draw by the coil as the engine cranks?
Posted on: 2018/5/18 17:44
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Re: 1937 ignition coil specs
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Home away from home
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Thanks to both of you for the information. I'll check this out.
Posted on: 2018/5/20 11:06
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Roger Howe
Whitewright, TX 1937 120C Touring Sedan |
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