Technical Mallory "Best" Coil - Resistor Required?

Just putting the finishing touches on my rewire of my tub. Yes, I'm converting back to 6v, and I'm using a Mallory C-5000 6-Volt "Best Ignition Coil".

But here's my dilemma: does this coil require an external resistor? I have the box, but the original info sheet is long gone, and a google 'n hamb search yielded nothing.

Anyone out there know?


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And because all threads are better with pictures...




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Check the resistance...you'll want 1.5 ohms (4 amps)

 

Sorry, hit enter too quickly. For a long happy life your points will thank you for feeding them no more than 4 amps. With a 6v system, 1.5 ohms is required to yield 4 amps (Voltage/Resistance = Amperage).

If your coil has less than 1.5 ohms resistance, you'll need a ballast resistor to keep from frying points (too much amperage to the points).

 

I have a few of those coils, mine all have the resistor on a ceramic collar around the secondary socket. Can't tell from your pic if that's the case with this one as it's mounted pointing down.

 

Thanks guys. I'll get the multimeter out and figure it out.

I have seen coils similar to mine with the white ceramic collar around the snout of the cap. Mine doesn't have that collar, but has three terminal posts, two of which are jumpered together with a heavy gauge wire.


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Someone removed your resistor and the ceramic mounting from the coil. The Mallory resistor is 0.5 ohm. plus you also use the Ford resistor. The Mallory resistor is not necessary, but it's resistance will help reduce the current through the points, so you can replace the Mallory with a second Ford resistor both wired in series, or replace both the Ford and Mallory resistor with another with a value of 1.0 Ohm. As mentioned above you want to limit point load to 3.5 to 4.0 Amp. The Mallory condenser works well with this coil.

 

So, I rung out my coil and like I said before there are three 'poles' on the cap, with a wire jumped between the outermost two (we'll call them 1 and 3), the center one (number two) is all alone.

I measured between 1 and 2 and got 1.8 Ohms. When I measured between 3 and 2 I got a reading between 3.1 and 3.8 Ohms. And just on a whim, I popped the 'wire', which I can now see was definitely machine formed, off and rung it out from end to end. Guess what, 1.8 Ohms.

So, I guess, no I don't need a resistor, as long as I connect poles three and two to the car. The coil is now more of a mystery though. It shows no indication of ever having the normal Mallory ceramic resistor on the 'snout' of the high-tension terminal, and the 'wire' I speak of is definitely supposed to be there. So why the variation? Is this an earlier or later coil, I wonder?

 

I use one on a 6 volt flathead.
Has the springy resistor wire and that's about it.
Show us a pic of the top if you can,
I'm curious as to what it looks like.
TP

 

Here's a picture of mine...



...sorry about the quality, just an upside down weird angle with a phone camera.

In this pic, the poles would be 3, 2, 1 from left to right.


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You need to use the arrangement that measures 1.8 ohms, not the one with more resistance!! With 6v at 1.8 ohms, you'll deliver 3.333 amps to the breaker points.

I wonder if the extra post (3.5 ohms or so) might be for 12v (12v/3.5ohm = 3.43 amps)

 

Thanks gwhite,

I guess I'll be hooking up to poles 1 and 2. When I get ready to apply power, I'll make sure to have the multimeter handy for pre-cranking checks.


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The top of the coil will have the markings + (your #3 terminal), - (your #2) . If you remove what appears to be a home made jumper from the top #1 term to #3 (+) terminal and take ohm readings, this is what you should have: - to 1=0.7 ohm, + to 1= open circuit, + to - = open circuit. - to High Voltage terminal= 10.39K ohm, + to HV= open, 1 to HV= open.
With a good C5000 coil with the original resistor removed and replaced by a jumper you want to use an external resistor to limit the point load. Without a external resistor the point load would be about 10. Amp which is too much. Using an external resistance in series with the coil with a value of 1.0 ohm the point load drops to 4.1 Amp. This should be good. If you can't find a 1. ohm resistor you could go to 1.3 ohm. this will give a point load of about 3.5 Amp.

 

Here's a couple of pictures of my stock coil with the resistor in place.

 

Hey I have a Mallory c5000, never been used still complete in the box with brackets and the documentation. Just curious what they were used for and what they are worth, found it hidden away in my grandfathers garage, he had multiple of everything we've found in different places so we will probably come across a few more. And info on this is appreciated

 

Any one have some directions on wiring this up, what about the capacitor?

 

First thing I'd do is verify the secondary resistance; 48-760 gave the specs (post #13)

As for wiring it up, just remember that the ground always goes to the points; if you're + ground, the + side goes to the distributor.

If you're not using the Model A pop-out switch, I'd wire the - side of the coil like the Model B; wire from the "discharge" side of the ammeter to ignition switch; wire from ignition switch to - side of the coil.