Replacing the electronic ignition with points - 1977 400 4V

[RemCharger]

I have the 2 pin right now. What size do I need?

What is the resistance measurement?

 

[Nacho-RT74]

As far I recall, 1.5 ohms is the propper one for points. 0.5 for electronic ignition

 

[Blue Brick]

What is the resistance measurement?

1.5

 

[Vaanth]

I have the 2 pin right now. What size do I need?

In short, to replicate the 1961 - 1972 contact points ignition system ballast resistor, a 0.5 ohm at 70-80 degrees Fahrenheit, open back, thermal/current compensating resistor is required.

Note that you should have a compatible coil, although your current coil with electronic ignition may be okay. The Chrysler 1960s - 1979 production coil resistance at 70-80 degrees Fahrenheit measures 1.6 - 1.79 ohms for the Prestolite 2444242 type coil and 1.34 - 1.55 ohms for the Essex/Echlin 2444241 type coil.

For more information, about production two terminal Chrysler ballast resistors and some aftermarket replacements, see the following.

---

The Chrysler ignition ballast resistor used in the 1960s through 1972 for the factory Chrysler single contact point distributor, and those with the Prestolite built dual point distributor is an open back, ceramic power resistor. This ballast resistor measures 0.5 - 0.6 ohms at 70-80 degrees Fahrenheit and has specific, expected thermal design properties.

The resistor you have now might be okay with points, depending on what resistance unit was in the electronic ignition kit that was installed. Aftermarket can vary, and discounting Direct Connection kits with four terminal ballast resistors, the early Mopar Performance kits with 4-pin electronic control units (ECUs) contained a 0.5 ohm resistor. Later Mopar Performance kits contained a 1.2 ohm resistor.

The two terminal 0.5 ohm thermal/current compensating ballast resistor used with the Chrysler point ignition system is part number 2095501, or the superseded numbers 2196316 or 2275590. The late 1970s Chrysler replacement number is 4106140. The Mopar replacement is CH452. These are all 0.5 ohm resistors with the metal strap, although some later manufactured units might be with a molded mounting hole. These are generally open back, although later issues such as 2275590 and 4106140 might have a sealed back. The Mopar Performance P2095501 is a 0.5 ohm resistor.

Some aftermarket replacement 0.5 ohm ballast resistors, although not all, are as follows:

• Standard RU-11//RU-11T
• Wells CR-107
• Filko CH401
• Kem FR56
• Echlin ICR 12
• Niehoff AL125C

Note that later manufactured aftermarket, or even Chrysler, resistors may be substituted with the 1.2, or 1.25, ohm resistor, which will work, but the ignition coil generated energy will be less. The current compensation for temperature is not the same though point contact life might be longer.

The 1.25 ohm two terminal ballast resistor was first used by Chrysler in 1980 for the "new" 4-pin ECU. The Chrysler part number for the 1.25 ohm resistor is 4106340, superseded to 5206436. The Mopar number is CH458. These resistors have a molded mounting hole with no metal strap and a sealed back. Some listings show 5206436 as 1.0 ohm. Others show it as 0.7 ohm. Mopar Performance P5206436 is a 1.25 ohm resistor, but some listings also show it as a 1.0 ohm or 0.7 ohm resistor.

Some aftermarket replacement 1.25 ohm ballast resistors, although not all, are as follows:

• Wells CR-107
• Standard RU-11/RU-11T
• WVE 6R1007
• Airtex 6R1007
• Filko CH901

Note the re-use of the same number for the 0.5 ohm resistor by some of these manufacturers.