Denso 5719 Spark Plug

Denso Iridium Racing Spark Plug for Mazda RX-7

Denso Iridium Racing 5719 is a race-focused spark plug built for serious Mazda RX-7 applications. It combines an iridium center electrode with a platinum ground tip and a 0.7 mm pre-gap for precise ignition performance in demanding secondary ignition use.

Key Features

• Iridium center electrode tip material for stable spark delivery
• Full platinum ground electrode tip design
• 0.7 mm pre-gap size
• 5000 ohm resistance
• 14.00 mm thread diameter with flat seat type
• 21.50 mm reach and 20.6 mm hex size
• Manufacturer heat range 27
• Nickel ground electrode core and copper center electrode core

Iridium Racing Line Details

The Denso Iridium Racing line is aimed at high-demand ignition service where consistent firing characteristics matter. Part number 5719 is part of that line and is specified for Mazda RX-7 leading plug applications across multiple rotary engine years.

Detailed Description

Denso 5719 is a secondary ignition spark plug engineered for Mazda RX-7 rotary applications that call for a race-oriented plug specification. The iridium center electrode, platinum ground tip, and slant ground configuration support focused spark delivery, while the heat range 27 specification and 5000 ohm resistance provide a defined ignition setup for performance use. This part cross-references DENSO Auto Parts (e.g., IRE01-27) for the same application.

Compatible With 1993-1995 Mazda RX-7, Leading; Iridium Racing. Compatible With 1986-1991 Mazda RX-7, Leading; Iridium Racing. Compatible With 1980-1985 Mazda RX-7, Qty 2 Per Rotor; Iridium Racing.

Common Issues This Part Addresses

• Misfire caused by worn or inconsistent spark plug electrodes
• Hard starting from degraded ignition performance
• Rough idle in rotary engine secondary ignition service
• Loss of throttle response from weak spark delivery
• Maintenance replacement for Mazda RX-7 leading plug applications

Installation Notes and Tips

Verify the thread diameter, reach, seat type, and heat range before installation on your Mazda RX-7. Check the pre-gap specification against the engine’s ignition requirements and confirm the plug is being used in the correct leading position noted in the fitment data. Follow the vehicle service manual for torque and inspection procedures.

Quality Assurance

Denso manufactures this Iridium Racing spark plug to published dimensional and material specifications for the listed Mazda RX-7 applications. Confirm fitment by year, engine position, and service notes before installation.