Symptoms
Hard starting, rough idle, hesitation and poor economy. Hagerty calls ignition the weak point of AMC-engined CJs, and Jeep-CJ.com's write-up blames the factory Duraspark.
The fix, step by step
- Start with a cap, rotor, plugs and wires.
- For a bigger upgrade, the Jeep-CJ.com HEI swap uses a 1976–82 GM inline-six HEI distributor with an AMC V8 drive gear.
- Mark the No. 1 position, remove the old distributor, install the HEI and run it from the constant-12 V firewall wire, not the resistor coil feed.
- Gap the plugs to .045 in.
- The firing order is 1-5-3-6-2-4.
- Set the timing with a light; the write-up says many owners use about 8° BTDC.
- CJs with a feedback ECM need it bypassed first.
Tools & part numbers
- Timing light
- volt meter
- soldering iron
- plug gapper
- HEI distributor and AMC V8 drive gear
- 8 mm plug wires
Where to buy the parts
Crown J8128445 distributor pickup, 1977–90 CJ/YJ 4.2LQuadratec ↗Amazon ↗
Performance Distributors DUI distributor, 1972–90 CJ 232/258Quadratec ↗Amazon ↗
Crown J4488760 points and condenser kit, 1966–74 CJ-5 6-cylQuadratec ↗Amazon ↗
Distributor cap, 1968 CJ-5 225 V6RockAuto ↗Amazon ↗
Hunting a used or discontinued part? Search eBay Motors for Jeep CJ-5 parts →
Rated for a competent home mechanic with a decent tool kit. Confirm torque figures, fluids and procedures against the factory service manual for your VIN, support the truck on stands rather than a jack, and work at your own risk (disclaimer). Some parts links are affiliate links, which pay us a small commission at no cost to you.