Autolite 275 Spark Plug

Autolite 275 Copper Spark Plug Overview

Autolite 275 is a copper non-resistor spark plug built for OE-style fit, form, and function across a range of classic domestic and import applications. It is specified for quick starts, steady idle quality, improved fuel economy, and smooth acceleration in vehicles such as the Jeep Wagoneer, Buick Skylark, and Mercedes-Benz 300SEL.

The Autolite Copper Non-Resistor Spark Plug line focuses on dependable ignition performance at a value price, making it a practical OE-style replacement for older engines that call for a copper-core plug with a flat seat and 0.025-inch pre-gap.

Key Features

• Copper center electrode core for consistent ignition response
• Non-resistor design for applications that specify a no-resistor plug
• Nickel center and ground electrode tip materials
• Tapered ground electrode tip design with one ground electrode
• Ceramic insulator with short insulator type
• Flat seat, 14 mm thread diameter, 13/16 in. hex size
• 0.500 in. reach and 0.025 in. pre-gap
• Removable nut terminal for common ignition wire setups

Detailed Description

Autolite 275 is an OE-style spark plug engineered for older ignition systems that require a copper non-resistor design. Its copper core supports reliable spark delivery, while the nickel electrode materials and tapered ground electrode help maintain stable combustion characteristics in the applications listed. This part number is a direct fit for select vehicles including 1970-1974 Land Rover Range Rover, 1970-1971 Mercedes-Benz 300SEL, 1963-1967 Jeep Wagoneer, 1961-1964 Buick Skylark, and 1956-1961 Fiat 500. Autolite 275 also cross-references Champion Spark Plug 312 for the same application.

What It Helps Address

• Hard starting in older ignition systems
• Rough idle caused by worn or incorrect spark plugs
• Reduced throttle response during acceleration
• Misfire concerns from plugs that do not match OE-style specifications
• Fuel economy loss related to weak or inconsistent spark

Installation Notes and Tips

Verify the engine’s required thread diameter, reach, seat type, and gap before installation. Autolite 275 uses a 0.025-inch pre-gap, a 14 mm thread, a 0.500-inch reach, and a flat seat, so it should be matched to the exact engine specification. Check the ignition wire terminal style and confirm the removable nut terminal is appropriate for the vehicle. For fitment examples, this part fits 1963-1967 Jeep Wagoneer, 1961-1964 Buick Skylark, and 1970-1971 Mercedes-Benz 300SEL in the listed OE-style applications.

Quality Assurance

Autolite supplies ignition products to the automotive aftermarket and original equipment manufacturers, and this spark plug is built to OE form, fit, and function standards for the listed applications. The Autolite 275 part number is intended for buyers seeking a direct replacement spark plug with the specified copper non-resistor construction.