Autolite 403 Spark Plug

Overview of Autolite Copper Resistor Spark Plug 403

The Autolite Copper Resistor Spark Plug 403 is engineered to deliver reliable ignition performance for a range of vehicles including Chevrolet, Honda, Pontiac, Porsche, and Volkswagen models. Designed with a copper core and resistor technology, this spark plug supports efficient combustion and reduces electrical interference.

• Resistance rating of 5000 ohms for noise suppression
• Tapered ground electrode tip made of nickel for durability
• Copper center electrode core with nickel tip for optimal conductivity
• Removable nut electrical terminal type for easy installation
• Flat seat type with a 0.750 inch (19.5 mm) reach
• Pre-gap size of 0.034 inches (0.90 mm) for precise spark delivery
• Hex size options of 13/16" (21 mm) for compatibility with standard tools
• Ceramic short insulator for heat resistance and electrical insulation

About the Copper Resistor Spark Plug Product Line

The Autolite Copper Resistor Spark Plug line combines copper core electrodes with resistor technology to reduce radio frequency interference while maintaining strong spark energy. This product line is designed to meet the ignition needs of various domestic and import vehicles, providing a balance of performance and durability. The 403 part number is a representative model within this line, featuring a standard center electrode design and nickel ground electrode tip for consistent ignition.

Technical Details and Compatibility

The Autolite 403 spark plug features a single nickel ground electrode with a tapered tip, enhancing spark exposure and combustion efficiency. The copper core center electrode improves thermal conductivity, helping to dissipate heat effectively. Its flat seat and 14.0 mm thread diameter ensure a secure fit in compatible engines. This spark plug is compatible with Chevrolet models such as the Bel Air, C10 Suburban, Corvette, El Camino, Impala, K10/K20 Suburban, Malibu, Monte Carlo, Nova, and Parisienne. It also fits Honda Accord, Civic, and Prelude, Pontiac Laurentian, Porsche 911, and Volkswagen Vanagon models.

Applications and Problem Solving

• Restores proper ignition in engines experiencing misfires
• Reduces radio frequency interference affecting vehicle electronics
• Improves fuel efficiency by ensuring consistent spark delivery
• Prevents fouling and electrode wear in high-heat conditions
• Supports smooth engine starting and idle stability

Installation Notes and Tips

• Verify correct spark plug gap of 0.034 inches (0.90 mm) before installation
• Use a 13/16" (21 mm) socket wrench for proper torque application
• Ensure the flat seat matches the engine’s cylinder head design
• Check reach length of 0.750 inches (19.5 mm) to avoid interference with piston or valves
• Replace spark plugs in sets to maintain balanced engine performance

Quality Assurance and Warranty

Autolite spark plugs are manufactured to meet industry standards for ignition components. The Copper Resistor Spark Plug 403 undergoes rigorous quality control to ensure consistent resistance and electrode integrity. While specific warranty details are not provided, Autolite products typically come with manufacturer-backed quality assurance to support reliable operation in compatible Chevrolet, Honda, Pontiac, Porsche, and Volkswagen vehicles.