Denso 4117 Spark Plug

Denso 4117 U-Groove Spark Plug

Denso 4117 is a conventional spark plug built around a U-groove ground electrode design for improved ignitability and more consistent combustion. It uses a copper center electrode core with nickel tip materials and a 5,000-ohm resistor for stable secondary ignition performance.

Key Features

• U-Groove ground electrode tip design for stronger spark exposure
• Conventional spark plug construction for routine ignition service
• Copper center electrode core material for dependable heat transfer
• Nickel center and ground electrode tip materials
• 5,000-ohm resistance for noise suppression in the ignition system
• Flat seat design, 12.00 mm thread diameter, 22.00 mm reach, and 18.0 mm hex size
• Manufacturer heat range 27 with a 0.7 pre-gap size

Detailed Description

The Denso U-Groove Conventional line focuses on practical ignition performance for drivers who want a direct spark plug replacement with OE-style construction. Part number 4117 uses a single ground electrode with a U-groove tip profile that helps expose the spark kernel more effectively, supporting cleaner ignition events and efficient engine operation. This spark plug is a strong match for service work on vehicles such as Honda Civic and Toyota Corolla applications where the correct thread diameter, reach, seat type, and heat range matter for proper combustion chamber fitment. This part cross-references DENSO Auto Parts (e.g., X27GPR-U) for the same application.

What It Helps Address

• Hard starting caused by worn or inefficient spark plugs
• Rough idle from inconsistent ignition firing
• Misfire conditions related to degraded plug electrodes
• Reduced fuel efficiency from incomplete combustion
• Loss of throttle response from weak spark delivery

Installation Notes and Tips

Verify the engine calls for a 12.00 mm thread diameter, 22.00 mm reach, flat seat, and 18.0 mm hex size before installation. Confirm the specified gap requirement against the vehicle service information; this plug is supplied with a 0.7 pre-gap size. Use proper torque procedures and inspect ignition wires or coils during service to avoid repeat misfire concerns. Compatible With Honda Civic and Toyota Corolla service applications only when the engine specification matches the listed plug dimensions and heat range.

Quality Assurance

Denso manufactures the 4117 as part of its U-Groove Conventional spark plug line, which is built around a design intended to improve ignitability and support efficient engine operation. Part number 4117 is engineered to meet the dimensional and electrical requirements listed above for accurate secondary ignition service.