Dash Wiring

Fillinjc

Fillinjc

Member
Hi,

Trying to get to the point of breaking in the newly rebuilt engine on my 1930 coupe. The PO had the ammeter wired with yellow to the charge side and the black terminal box wire to the positive side of the coil. I tried to follow Les Andrews manual and other info located on the Internet with yellow/black to the charge side of ammeter and black terminal box wire to the negative side of coil. Now with key on I see charge on the ammeter. That can't be right. Now I see in Brattons catalog for ammeter that yellow goes to charge side. Why the discrepancy? Is my coil ok with black wire to negative side of coil.

Thanks,
Jerry
 
Some repro ammeters are made so the wires needs to be swapped to read correctly.

The + on the coil should go to the points on a + ground system, but the engine will start and run fine either way. The plugs fire easier though when it's wired correctly, so you might experience a miss under a hard pull if you have the + and - mixed up on the coil terminals.
 
Per Tom - some repro ammeters read backwards and the wires need swapped. With the dash panel off, you can test which way the needle points (charge/discharge) by turning on the lights. Then you can correct the wiring by reversing the setup if the needle points to charge with the lights on. Then reinstall the dash. That is how I have tested replacement ammeters.

I have used this item from Bratton's to check for spark and coil polarity. I can't seem to read the "+" or "-" upside down on those coils with the hood on. Or if it an old coil and debris makes it difficult to read the "+" or "-". This device is quick and simple to use. If the coil polarity is wrong the LED lights on the device tell you it is reversed. Then it is another easy reversing of the wires on the coil (may need to rotate the coil 180 degrees in the mount since the red ignition wire is short).

https://www.brattons.com/ignition-spark-and-coil-tester.html

Brian
 
I'm looking at page 97 of the Bratton catalog and the online colorized "Dykes" drawing. I don't see any difference. Did you read the second note?

Do you have the car wired positive to ground or negative to ground?
 
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