Coil ?????
- Thread starter Seneca
- Start date
Lawson Cox
Well-known member
If you have cleaned the points and put in a new condenser without any change, I would go ahead and send the coil to Skip for a rebuild.
37slantback
Senior Member
Someone had hooked up my coil backwards and that can reduce the spark.
I had trouble with the resister. It would change resistance when it got hot. New one from NAPA is ICR40 at $9.95. The connections are also suspect due to the heat cycling.
I would hot wire it as a test. I also had resistance in the ignition switch. It had worn a groove and was not making good contact.
I would hot wire it as a test. I also had resistance in the ignition switch. It had worn a groove and was not making good contact.
Shorting out the resistor won't prove it's a bad coil. It will provide the full 7.5 volts to the coil makeing a stronger spark and will get you home if stuck on the road. However the coil will run hotter and can melt the tar out of the coil and burn the insulation on the windings if run to long. Hooking a coil up backwards will not change the output when hooked up to the correct polarity. A coil is similar to a transformer and is made of the steel laminations and a primary and secondary set of windings. If they have good insulation what's to go bad?? I prefer an old resistor to the new modern ones. Bend the slotted metal covers up, clean the ends where the resistor wire is clamped against the ends. Use ACID as a flux, push the nicrome wire against the end and solder both ends. Regular soldering flux won't work with the nichrome wire. As Andy metioned these old ignition switches get as he described and need cleaning or replacement. G.M.
Henry/Kokomo
Well-known member
Jeff - I would suggest that any '46 - '48 coil you buy today is likely to be suspect due to age. The surest way to get a known-to-be-good one is to send an original core to be rebuilt. Would further suggest Skip Haney. I had him rebuild a stock one, convert to 12v and reverse the polarity. He did all this at a reasonable price with fast service and it works like a charm. I've heard nothing but good things about his stock rebuilds also. FWIW.
Henry/Kokomo
Well-known member
The '46-'48 isn't exactly a tube type coil. It is a bakelite body having two mounting "ears" (that bolt to a bracket that attaches to the block with two intake manifold bolts), the secondary wire exits from the bottom of the coil and the primary leads attach to the top of the coil. I believe these are the Ford Part Numbers: Coil = P/N 1GA 12024 Mounting Bracket = P/N 21A12257
It only takes a certain amount of "spark power" to fire the plugs. To high of secondary voltage will cause the spark to "wonder" across the rotor, cap or other places where the high voltage travels. This causes the molded material to carbonize and become a resistive path to ground. On the other hand the spark must be strong enough so the compression don't blow the spark across the plugs to go out like a candle. A nice blue 3/8 to 1/2" spark from the spark plug wire to a head nut is good. Don't jump the spark to the plug terminal. When ALL of the stock Ford coils get hot the spark is reduced to a short yellow spark. When realy hot it is a fuzzy little yellow ball that will hardly fire. G.M.
I will share this for what it is worth. I had installed a new external resistance tube coil and it started and drove fine but the car would not start when hot. Another thread had the resitances listed. They are too low for me to measure. I do have the stock ammeter . It showed only 1 amp thru the coil. I put a original coil on it and it now shows 6 amps and will start when hot. This indicates to me I had a total resistance with the new coil of 6 ohms and only 1 ohm with the original coil. All thru a replacement external resister.
Should have mentioned that I'm using the FlameThrower coil with a PerTronix Igniter kit in distributor - BUT I installed the coil first and saw a big improvement even with the points, etc. before I put in the Igniter type ignition! Have had the total PerTronix system in for 3 or 4 years now and it has been super for me.