Denso 3066 Spark Plug

Denso 3066 U-Groove Spark Plug Overview

The Denso 3066 is a conventional spark plug built for steady ignition performance in a wide range of import and domestic applications. Its U-Groove ground electrode design helps improve ignitability for more efficient combustion, while the copper core and nickel electrode materials support consistent spark delivery.

Compatible With classic and late-model vehicles including Porsche 928, Volvo 240, and Volkswagen Golf applications, this plug is a practical OE-style replacement for drivers maintaining original ignition performance. The Denso 3066 is also cross-referenced to DENSO Auto Parts W20EXR-U for the same application.

Key Features

• U-Groove ground electrode tip design for improved ignitability
• Conventional spark plug construction for broad vehicle coverage
• Copper center electrode core material for stable heat transfer
• Nickel center and ground electrode tip materials
• 5000 ohm resistance for ignition system compatibility
• Flat seat design with 14.00 mm thread diameter
• 19.00 mm reach and 20.6 mm hex size
• Manufacturer heat range 20 with 0.8 pre-gap size

Product Details

The Denso U-Groove Conventional line focuses on dependable ignition performance through a ground electrode shape that exposes more of the spark to the air-fuel mixture. That design can support cleaner, more efficient combustion in engines that call for a conventional plug with this specification set. Part number 3066 is built with a nickel ground electrode core, nickel tip material, and a copper center electrode core to balance durability and heat control.

Fitment coverage includes applications such as Fits 1993-1995 Porsche 928, N/A; Fits 1991-1995 Volvo 940, N/A; Fits 1987-1989 Volkswagen Golf, N/A; Fits 1979-1988 Saab 900, N/A; and Fits 1967-1969 Chevrolet Camaro, N/A. Additional coverage extends across Porsche, Volvo, Volkswagen, Mercedes-Benz, Audi, Nissan, Toyota, Honda, Jaguar, and Chevrolet models listed in the fitment data.

What This Spark Plug Helps Address

• Hard starting caused by worn or inconsistent spark plugs
• Rough idle from weakened ignition output
• Misfire conditions related to aged secondary ignition components
• Reduced combustion efficiency from excessive electrode wear
• Maintenance replacement for vehicles requiring a conventional U-groove plug

Installation Notes and Tips

Verify the thread diameter, reach, seat type, and heat range against the vehicle’s service specification before installation. The pre-gap size is 0.8, so confirm the gap matches the engine requirement before threading the plug into the cylinder head. Use the correct 20.6 mm hex socket and follow the manufacturer’s torque specification for the engine.

Fitment examples include Fits 1984-1989 Porsche 911, N/A; Fits 1990-1993 Volvo 240, N/A; Fits 1985-1989 Volkswagen Cabriolet, N/A; Fits 1986-1987 Mercedes-Benz 560SL, N/A; and Fits 1973-1979 Honda Civic, N/A. Always confirm application details by year, make, model, and engine configuration before service.

Quality Assurance

Denso designs the U-Groove Conventional line around consistent ignition performance and OE-style fitment standards. Part number 3066 is engineered to meet the dimensional and electrical requirements listed here for the specified applications.