Denso 5020 Spark Plug

Denso 5020 U-Groove Conventional Spark Plug

Denso 5020 is a conventional spark plug built for older ignition systems that need reliable secondary ignition performance. Its U-Groove electrode design helps improve ignitability, supporting more efficient combustion in a wide range of classic Chrysler, Ford, GM, and Dodge applications.

Key Features

• U-Groove ground electrode tip design for improved spark exposure
• 5000 ohm resistor for reduced electrical noise
• Copper center electrode core for stable heat transfer
• Nickel center and ground electrode tip materials
• Standard ground configuration with one ground electrode
• Pre-gapped at 0.9 mm
• Tapered seat, 14.00 mm thread diameter, 11.60 mm reach
• Manufacturer heat range 14

Product Details

This Denso U-Groove Conventional spark plug is engineered around a simple, durable electrode layout that suits many carbureted and early electronic ignition setups. The U-shaped ground electrode helps expose the spark kernel more effectively, while the copper core and nickel electrode materials support consistent operation in secondary ignition service. Denso 5020 is a direct replacement option for vehicles such as the Chevrolet C10, Dodge D150, and Ford Thunderbird, along with many other classic truck and passenger car applications.

This part cross-references DENSO Auto Parts T14PR-U and Ford ASF52 for the same application.

Common Uses

• Restoring weak or inconsistent spark in older ignition systems
• Replacing worn plugs that cause rough idle or misfire
• Addressing hard starting in classic Chevrolet, Dodge, and Ford vehicles
• Improving combustion stability in high-mileage engines
• Replacing plugs with excessive electrode wear or fouling

Installation Notes and Tips

Verify thread diameter, reach, seat type, and heat range before installation. Denso 5020 uses a tapered seat and 14.00 mm thread diameter, so it should be matched carefully to the cylinder head specification. Check and confirm the pre-gap against the engine service manual before installation, especially on older engines with modified ignition components.

Compatible With 1976-1980 Chevrolet C10, N/A; 1978-1984 Dodge D150, N/A; 1985 Ford Thunderbird, N/A; and other listed applications across 1970-1985 Chrysler, Ford, GM, and Dodge vehicles.

Quality Assurance

Denso manufactures this spark plug as part of its U-Groove Conventional line, a product family focused on dependable ignitability and efficient combustion in conventional ignition applications. The design and material selection reflect Denso’s OE-oriented engineering approach for secondary ignition service.