Why Upgrade Your 1965 Plymouth Valiant to Electronic Ignition?

The stock points-and-condenser ignition system on a 1965 Plymouth Valiant was adequate for its time, but it’s far from ideal by modern standards. Points wear out, burn, and require periodic adjustment—usually every 10,000 to 12,000 miles. They also limit the coil’s output at higher engine speeds, leading to misfires and decreased performance. A Mopar electronic ignition system eliminates mechanical contact points, replacing them with a magnetic pickup and an electronic control module. The result is a stronger, more consistent spark, longer plug life, easier cold starting, and virtually maintenance-free operation. For owners who drive their Valiant regularly, this upgrade delivers better fuel economy, smoother idle, and increased reliability.

The Mopar kit (part number P3690426 or similar, depending on application) is a direct-fit upgrade for the 225 Slant Six or 273/318 V8 found in the 1965 Valiant. It includes a new distributor cap, rotor, magnetic pickup assembly, control module, ballast resistor, and wiring harness. Before diving in, be sure to source the correct kit for your engine family. Many classic Mopar enthusiasts also recommend upgrading to a high-output coil, such as the Mopar Performance P5249004, for even better spark energy.

Tools and Materials Needed

  • Mopar electronic ignition kit (check compatibility with your engine)
  • Basic hand tools: screwdrivers (flat and Phillips), combination wrenches (1/2", 9/16", 5/8"), socket set with extensions
  • Wire cutters, wire strippers, and crimping tool
  • Multimeter with DC voltage and ohms settings
  • Heat shrink tubing (assorted sizes) and a heat gun or lighter
  • Electrical tape and zip ties
  • Service manual for 1965 Plymouth Valiant (available as a reprint from eBay or classic car book retailers)
  • Timing light
  • Dielectric grease
  • Safety glasses and work gloves
  • Penetrating oil (for stubborn screws)

Preparation Steps

1. Disconnect the Battery

Always start by disconnecting the negative battery terminal. This prevents accidental short circuits while working on the electrical system. Wrap the terminal in a cloth or tape to keep it from accidentally touching metal.

2. Remove the Old Ignition System

Begin by removing the air cleaner and any brackets that obstruct access to the distributor and coil. Mark the position of the distributor body relative to the intake manifold or engine block with a scratch mark or masking tape – this helps preserve your initial timing setting. Remove the distributor cap, rotor, and then the points and condenser. Follow the service manual for your specific engine to disconnect the wiring between the points and the original coil. Remove the old ballast resistor (if equipped) and the original coil. Set all old parts aside; you may want to keep them as emergency spares.

3. Check the Distributor Base and Components

With the old points removed, inspect the distributor’s breaker plate and shaft for excessive wear or side play. The Mopar electronic ignition kit’s magnetic pickup assembly replaces the breaker plate entirely. Clean the distributor housing with brake cleaner and a rag. If the distributor shaft has noticeable play, consider rebuilding or replacing the distributor before installing the electronic system – a worn shaft will cause timing fluctuations and poor performance.

Refer to the detailed Mopar instructions (often available online at MyMopar.com’s technical library) for specific disassembly steps for your distributor model.

Installing the Electronic Ignition System

4. Install the Magnetic Pickup and Reluctor

Remove the old breaker plate and condenser. Slide the Mopar magnetic pickup (often called the “reluctor and stator” assembly) into the distributor housing. It typically snaps into place using two spring clips. Ensure the wire from the pickup is routed through the provided grommet in the distributor housing. Install the reluctor (the tooth wheel) on the distributor shaft, aligning the shaft’s flat spot. Secure it with the supplied roll pin or setscrew. Confirm that the reluctor teeth do not contact the magnetic pickup pole piece – use a feeler gauge to set the air gap between 0.006 and 0.010 inches if the kit allows adjustment. Many Mopar kits preset this gap, but it’s worth checking.

5. Mount the Electronic Control Module

Find a clean, flat surface on the firewall or inner fender that stays relatively cool. The Mopar module (a rectangular black box) must have a good thermal path to metal. Use the supplied bracket or a self-tapping screw to mount it. If you plan to use a high-output ignition coil, mount the module in a well-ventilated area. Some owners attach it by the driver-side inner fender using two ¼-inch bolts. Apply a thin layer of dielectric grease to the module’s mounting base to improve heat transfer.

6. Install the New Ignition Coil

The Mopar kit often comes with a standard epoxy-filled coil. Remove the old coil bracket and mount the new coil in the same location. Ensure the coil terminals are facing away from exhaust heat if possible. Connect the coil’s positive (+) terminal to the power wire from the ignition switch and to the module’s power lead. Connect the coil’s negative (–) terminal to the module’s tachometer output or coil negative wire, following the included wiring diagram. Many Mopar electronic ignitions require replacing the factory ballast resistor with the one included in the kit. This new resistor reduces voltage to the coil during idle and low load, protecting the module. Do not skip this step – using the wrong ballast can damage the module.

7. Wire the System

Using the Mopar wiring diagram, connect:

  • Red wire from module: to ignition switched +12V (or to coil positive if using a ballast resistor).
  • Black wire from module: to engine ground (clean bare metal).
  • Orange wire from distributor pickup: to the module according to diagram (typically two-wire connector).
  • Ballast resistor: one terminal to ignition +12V, the other to coil +. Coil – goes to module.
Use heat shrink tubing on all crimp connections and secure wires with zip ties away from hot engine surfaces. Double-check polarity – reversing the module’s wires can destroy the electronic components.

8. Install the Distributor Cap and Rotor

The new distributor cap and rotor are part of the kit. Place the rotor on the shaft (it only goes on one way). Snap the cap down, ensuring the carbon brush inside makes contact. Route the spark plug wires in the original firing order (1-5-3-6-2-4 for Slant Six; 1-8-4-3-6-5-7-2 for small block V8). Use the original wire separators to keep order clean.

Finalizing the Installation

9. Reconnect the Battery and Check Voltage

Reconnect the negative battery terminal. Turn the ignition key to the “Run” position (do not start the engine). Use a multimeter to measure voltage at the coil positive terminal. With the ballast resistor in circuit, you should see approximately 6–8 volts. When the starter is engaged, the resistor is bypassed and full battery voltage supplies the coil. If you see 12V all the time, check your wiring – the ballast resistor may be miswired or bypassed. A popular Allpar forum thread covers common wiring pitfalls.

10. Set Ignition Timing

Start the engine and let it warm up to operating temperature. Set base timing using a timing light. For the 225 Slant Six, the factory setting is typically 10° BTDC at idle (with vacuum advance disconnected and plugged). For the 273 V8, it varies between 5° and 10° BTDC. Adjust by loosening the distributor hold-down bolt and rotating the distributor body counterclockwise (advance) or clockwise (retard). Tighten the bolt and recheck. Reconnect the vacuum advance and rev the engine to confirm the mechanical advance works smoothly between 2,000–4,500 RPM total advance (usually around 32–38° total).

11. Test Drive and Verify Performance

Take the Valiant on a test drive. Acceleration should be crisp, and the engine should idle smoothly even when hot. Listen for any detonation (pinging) under load. If you hear pinging, the base timing may be too advanced; retard 2° and retest. Also verify that the tachometer works correctly – many Mopar electronic ignitions provide a tach output signal. If your original tachometer doesn’t function, you may need a signal adapter.

Troubleshooting Common Issues

Even with careful installation, you may encounter problems. Here are the most common fixes:

  • No spark after installation: Check that the ballast resistor is not burnt open (disconnect the negative wire and meter across the terminals – should show 0.5–1.2 ohms). Verify module ground wire is secure and clean. If the module gets hot instantly, it may have failed. Swap in a known good module to test.
  • Engine starts then dies: This often points to a faulty ballast resistor or incorrect wiring. The bypass wire (from starter solenoid to coil positive) may be missing. That wire provides full 12V during cranking.
  • Intermittent misfire at high RPM: The air gap between the reluctor and pickup may be too large or too small. Recheck 0.006–0.010 inches. Also verify cap and rotor condition – cheap parts can cause high-speed misfire.
  • Rough idle: Check for vacuum leaks, especially if the distributor was disturbed. Also confirm that the pickup wires are not coming into contact with the reluctor shaft.

If you continue to have trouble, the For A Bodies Only electrical section is a rich resource of Mopar-specific diagnostic advice.

Performance and Maintenance Notes

With the Mopar electronic ignition installed, you can now run a larger spark plug gap – typically .035–.045 inches for street driving – to ignite leaner fuel mixtures. The system tolerates slightly higher RPM ranges without misfire. Expect improved fuel economy by 1–3 miles per gallon. Maintenance reduces to checking the cap and rotor every 30,000 miles and replacing the module only if it fails. Keep a spare module in the glove box; modern replacements are affordable from RockAuto.

Conclusion

Converting a 1965 Plymouth Valiant from points to Mopar electronic ignition is a straightforward weekend project that dramatically improves driveability and reliability. By following the detailed steps above—prepping the distributor, mounting the module, wiring with the correct ballast, and verifying timing—you can eliminate the shortcomings of the original system and enjoy a smoother, more powerful engine. Classic Mopars respond exceptionally well to this upgrade, and the peace of mind gained is well worth the effort. Add electronic ignition to your Valiant and rediscover why these cars were legendary on the street.