new guy needs help testing coil .

G

gas man

Member
so I picked up a old 39 merc with the original flathead In it. I dont have any spark so I'm trying to test the coil . I took the coil out of the car and with one lead on the on the top post where the wire connects and the other lead where the little stud thing is that sits on the the rotor , I'm getting 26k. isn't that double what it should be ?
 
If it is an original coil. have it rebuilt or replace it. Testing a coil with an ohmmeter will tell you is the winding is intact, but not whether or how many windings have breached the insulation, and are shorting. At our shop, we send them all to Skip Haney for the rebuild, $85. Phone 941/637-6698 or 941/505-9085. Gmail:skip@fordsrus.com The original coils have a paper insulator that disintegrates over time. Almost all vehicles benefit for rebuild.
 
Couple of questions, is the car still 6v positive ground? Voltage to the coil should be in the 4 volt range. Start checking for voltage (6+) at the ignition switch and then the ballast resistor under the dash. Might take a look at Babb's ignition site online for a lot of general information. VanPelt flatheads is also a good site with a lot of information and wiring diagrams.
 
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With the coil connected and the points closed the voltage at the coil should not be 6v, it should be more like 4v. The ballast resistor should be dropping the voltage down to the coil.
 
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