Autolite 666 Spark Plug

Autolite Copper Resistor Spark Plug Overview

The Autolite Copper Resistor Spark Plug part number 666 is engineered to deliver reliable ignition performance for a wide range of vehicles including Buick, Chevrolet, Ford, and Jeep models. Designed with durable materials and precise specifications, this spark plug supports efficient combustion and consistent engine operation.

• Resistance: 4000 ohms for effective electrical noise suppression
• Center electrode made of copper core with nickel tip for optimal conductivity and durability
• Single tapered ground electrode with nickel tip and nickel core material
• Pre-gap size of 0.060 inches (1.50 mm) for proper spark gap
• Tapered seat type and mid-projection ceramic insulator for secure fit and insulation
• Stud type electrical terminal and 5/8 inch (16 mm) hex size for standard installation
• Thread diameter of 14.0 mm and reach of 0.433 inches (11.0 mm) to match OEM specifications

Details on the Copper Resistor Spark Plug Line

The Copper Resistor Spark Plug line by Autolite is designed to reduce radio frequency interference while maintaining strong ignition performance. The resistor type spark plug with 4000 ohms resistance helps minimize electrical noise that can affect vehicle electronics. This line combines copper core electrodes for excellent heat dissipation with nickel tips for wear resistance, making it suitable for many domestic vehicles.

Technical Description and Compatibility

This spark plug features a standard center electrode design with a copper core and nickel tip, providing a balance of conductivity and durability. The single tapered ground electrode with nickel core and tip ensures consistent spark delivery. The ceramic insulator with mid-projection design offers reliable insulation and heat resistance. With a pre-gap of 0.060 inches, tapered seat, and thread diameter of 14.0 mm, this spark plug meets OEM fitment requirements for models such as the Chevrolet Camaro, Ford Mustang, Buick LeSabre, and Jeep CJ7.

Common Applications and Problem Solving

• Restores proper ignition timing and spark delivery in older domestic vehicles
• Reduces radio frequency interference affecting vehicle electronics
• Improves engine start-up reliability and smooth idling
• Addresses misfires caused by worn or damaged spark plugs
• Maintains consistent combustion efficiency for better fuel economy

Installation Notes and Tips

• Verify correct gap of 0.060 inches before installation
• Use a 5/8 inch (16 mm) spark plug socket for proper torque application
• Ensure tapered seat matches cylinder head specifications for a secure fit
• Apply anti-seize compound sparingly on threads if recommended by vehicle manufacturer
• Check for proper reach of 0.433 inches (11.0 mm) to avoid engine damage

Quality Assurance and Warranty

Autolite Copper Resistor Spark Plugs are manufactured to meet or exceed OEM standards for ignition components. The use of high-quality copper and nickel materials ensures durability and consistent performance. While specific warranty details may vary, Autolite products typically come with a limited warranty against manufacturing defects. Always consult vehicle service manuals and Autolite documentation for proper maintenance and warranty information.