Denso 4124 Spark Plug

Denso 4124 U-Groove Spark Plug

Denso 4124 is a conventional spark plug built for reliable secondary ignition performance in older Jeep applications. Its U-Groove ground electrode design promotes stronger ignitability, helping support smoother combustion and efficient engine operation.

Key Features

• U-Groove ground electrode design for improved spark exposure
• Copper center electrode core for dependable heat transfer
• Nickel center electrode tip and nickel ground electrode tip
• 5000 ohm resistor for ignition noise suppression
• Flat seat, 14.00 mm thread diameter, 19.00 mm reach
• Pre-gapped to 1.0 mm
• Manufacturer heat range 16

Product Details

This Denso U-Groove Conventional spark plug is engineered around a standard ground configuration with a single ground electrode and a 20.6 mm hex size for serviceability. The U-shaped ground tip helps expose the spark kernel more effectively than a conventional flat design, supporting cleaner ignition in engines that call for this specification. Part number 4124 also cross-references DENSO Auto Parts J16HR-U10 for the same application.

Compatible With 1980 Jeep Cherokee, N/A; 1980 Jeep CJ5, N/A; 1980 Jeep CJ7, N/A; 1980 Jeep J10, N/A; and 1980 Jeep Wagoneer, N/A. For buyers searching for a 1980 Jeep Cherokee spark plug, 1980 Jeep CJ7 ignition tune-up part, or Denso 4124 replacement, this plug matches the listed fitment and design requirements.

What It Helps Address

• Hard starting caused by worn or inconsistent spark plugs
• Misfire from weak ignition at the plug gap
• Rough idle in older Jeep engines
• Reduced combustion efficiency from aged secondary ignition components
• Ignition noise that can interfere with electrical systems

Installation Notes

Verify the thread diameter, reach, seat type, and heat range against the engine specification before installation. Check the pre-gap setting against the vehicle service manual and confirm the plug boots and ignition wires are in good condition. Use proper torque during installation to protect the cylinder head and maintain consistent sealing.

Quality Assurance

Denso manufactures this spark plug as part of its U-Groove Conventional line, a product family focused on improved ignitability through electrode geometry and proven ignition materials. Part number 4124 is built to the listed specifications for direct replacement service in the confirmed Jeep applications.