Autolite 66 Spark Plug

Autolite 66 Copper Resistor Spark Plug

Autolite 66 is a copper resistor spark plug built for OE-style form, fit, and function across a wide range of classic and older import and domestic applications. It is specified for quick starts, smooth acceleration, and dependable ignition performance in vehicles such as BMW 528e, Mercedes-Benz 560SEL, and Dodge Charger applications.

Key Features

• Copper center electrode core for consistent ignition response
• Nickel center and ground electrode tip materials
• 4,000 ohm resistor design for radio-frequency noise suppression
• 0.034 in. pre-gap size for OE-style service replacement
• Flat seat, 14.0 mm thread diameter, 0.750 in. reach
• Mid-projection ceramic insulator with a tapered ground electrode tip
• Removable nut terminal for common ignition wire setups

Product Details

The Autolite Copper Resistor Spark Plug line is positioned as an OE-style replacement for foreign and domestic vehicles that call for a conventional copper plug. Part number 66 uses a standard/regular center electrode design with a single ground electrode and nickel tip materials to support stable spark delivery. The copper core helps maintain reliable conductivity, while the resistor construction supports cleaner ignition operation in applications that specify a resistor plug.

This part cross-references Autolite 86 and National 1196 for the same application. It is a direct service option for many older BMW, Mercedes-Benz, Dodge, Pontiac, Chevrolet, and Cadillac engines that require the listed thread, reach, seat, and gap specifications.

What This Spark Plug Helps Address

• Hard starting caused by worn or fouled spark plugs
• Rough idle from inconsistent ignition firing
• Misfire symptoms tied to aged plug electrodes
• Reduced throttle response in older ignition systems
• Radio interference in resistor-plug applications

Installation Notes and Fitment

Verify thread diameter, reach, seat type, and gap before installation. This plug is listed with a 0.034 in. pre-gap, but many engines require final gap verification during service. Compatible With 1989-1992 Land Rover Range Rover, N/A; 1990-1992 Pontiac LeMans, N/A; 1986-1991 Mercedes-Benz 560SEC, N/A; 1987-1991 Mercedes-Benz 560SEL, N/A; 1990-1991 Pontiac Optima, N/A; 1990-1991 Pontiac Sunbird, N/A; 1987-1989 Mercedes-Benz 560SL, N/A; 1988 BMW 528e, N/A; 1985-1988 BMW 535i, N/A; 1988 BMW 535is, N/A; 1984-1987 BMW 325e, N/A; 1986-1987 BMW 325es, N/A; 1982-1987 BMW 528e, N/A; 1985-1987 BMW 635CSi, N/A; 1985-1987 BMW 735i, N/A; 1984-1985 BMW 318i, N/A; 1984-1985 Mercedes-Benz 500SEC, N/A; 1984-1985 Mercedes-Benz 500SEL, N/A; 1983-1984 BMW 533i, N/A; 1980-1983 BMW 320i, N/A; 1979-1981 BMW 528i, N/A; 1960-1975 Dodge Dart, N/A; 1970-1974 Cadillac Commercial Chassis, N/A; 1970-1974 Cadillac DeVille, N/A; 1970-1974 Cadillac Eldorado, N/A; 1970-1974 Cadillac Fleetwood, N/A; 1967-1974 Dodge Charger, N/A; 1971-1973 Chrysler Newport, N/A; 1970-1973 Dodge Challenger, N/A; 1968-1973 Dodge Monaco, N/A; 1969-1970 Chevrolet Nova, N/A; 1962-1970 Pontiac Acadian, N/A; 1968-1969 Buick Skylark, N/A; 1963-1969 Chevrolet Bel Air, N/A; 1967-1969 Chevrolet Camaro, N/A; 1967-1969 Chevrolet Caprice, N/A; 1963-1969 Chevrolet Impala, N/A; 1967-1969 Oldsmobile Cutlass, N/A; 1964-1967 Chevrolet Malibu, N/A; 1967 Dodge Charger, N/A; 1966-1967 Pontiac Laurentian, N/A; 1966-1967 Pontiac Parisienne, N/A; 1965 Jeep Wagoneer, N/A; 1964-1965 Pontiac LeMans, N/A; 1964-1965 Pontiac Tempest, N/A; 1961-1962 Dodge Lancer, N/A; 1955-1956 Chrysler Newport, N/A; 1955-1956 Chrysler Town & Country, N/A; 1955 Chrysler 300, N/A; 1955 Chrysler Imperial, N/A; 1955 Chrysler New Yorker, N/A.

Quality Assurance

Autolite supplies ignition products to the automotive aftermarket and original equipment channels, and this copper resistor spark plug follows OE-style specifications for fit and function across the listed applications. Part number 66 is built to match common service requirements for older ignition systems.