Voltage resistor for coil.

[deeprock]

So I have finally got my LB block assembled and installed in my 35 coupe. The resistor under the dash for the coil gets really hot, so hot the insulator base starts to stink. I believe it is functioning properly 6.3 volts in and just under 3 out. And ideas. Wiring is all new. And the voltage at the coil is near the same value.

[Kurt in NJ]

is it a repro from Macs with screws on the ends----and instead of a ceramic inner core it has bamboo----as it chars it smells like a 3rd world brush fire

[deeprock]

It's from Macs, I wonder how long that will last?

[JM 35 Sedan]

Originally Posted by Kurt in NJ

is it a repro from Macs with screws on the ends----and instead of a ceramic inner core it has bamboo----as it chars it smells like a 3rd world brush fire

LOL Kurt, those wire wound resistors will get hot, that's what they do when functioning correctly. Now if that resistive wire is wound on something other than a ceramic material, or equivalent, you will more than likely get that stinky smoking condition.

It may be possible to find an nos or good used original resistor that will work better than some of the repro parts that are being sold today.

[FlatheadTed]

See here
https://www.fordbarn.com/forum/showthread.php?t=195119

[Mac VP]

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We still have some NOS resistors, and I'm sure some of the other vendors do as well. This is what the original 18-12250 resistor looks like.
http://www.vanpeltsales.com/FH_web/F...0-resistor.jpg

[koates]

deeprock, just under 3 volts out of the resistor and at the ignition coil is way too low. You should have at least 4 volts and preferably 4.5 volts. What is the voltage at the ignition switch and across the battery ? should be 6.3 volts for a good battery. What ignition coil are you running ? Another test is to connect an ammeter in series at the coil ignition feed from the resistor and measure the current draw of the coil with the distributer contacts closed. Should not be any more than approx. 3 amps. All these things are very important for a good running ignition system. As others have said , throw away that repop resistor and fit a NOS original Ford unit. Regards, Kevin.

[G.M.]

Originally Posted by deeprock

So I have finally got my LB block assembled and installed in my 35 coupe. The resistor under the dash for the coil gets really hot, so hot the insulator base starts to stink. I believe it is functioning properly 6.3 volts in and just under 3 out. And ideas. Wiring is all new. And the voltage at the coil is near the same value.

Go back and look at past posts I have posted several times on how
to repair the original resistor so it's better than new. The resistor is
going to get hotter with the engine not running than when it's running
if the points are closed it is just a shorting of the coil wires. G.M.

[deeprock]

Thanks guys, Tossing the brand new one, it's junk the more I drive the hotter it get and the more the voltage drops.

[rotorwrench]

A wire wound power resistor drops the voltage through heating of the windings. This is why the OEM part has the metal shield to protect its surroundings from the heat. It is ain't hot it ain't workin. I would go for the OEM type until they are no longer available.