miata spark plugs

Spark plugs are an essential component of a Mazda Miata’s ignition system, responsible for igniting the air-fuel mixture within the combustion chamber. This guide will provide information on the different spark plugs used in various Miata models, maintenance intervals, necessary tools, and performance options.

Original Equipment Spark Plugs by Model:

NA (1989-1997):

  • 1.6L (1989-1993): NGK BKR6E-11 (copper)
  • 1.8L (1994-1997): NGK BKR5E-11 (copper)

NB (1998-2005):

  • 1.8L (1998-2000): NGK BKR5E-11 (copper)
  • 1.8L VVT (2001-2005): NGK ZFR6F-11 (platinum)

NC (2006-2015):

  • 2.0L (2006-2015): NGK LFR5A-11 (platinum)

ND (2016-2021):

  • 2.0L (2016-2021): NGK PFR6M (iridium)

Maintenance Intervals:

  • Copper: Check and adjust the gap every 30,000 miles, replace every 60,000 miles
  • Platinum: Check and adjust the gap every 60,000 miles, replace every 90,000-100,000 miles
  • Iridium: Check and adjust the gap every 60,000 miles, replace every 100,000 miles

Note: These intervals may vary depending on factors such as modifications, usage, and driving conditions.

Tools Needed:

  • Spark plug socket (5/8″ or 16mm)
  • Ratchet with extension
  • Torque wrench
  • Feeler gauge or spark plug gap tool
  • Anti-seize compound (optional)
  • Dielectric grease (optional)

Performance Spark Plugs:

For performance, racing, or forced induction engines, consider upgrading to the following spark plugs:

  • NGK Iridium IX (heat range 6-9): Higher heat range options for better heat dissipation in high-performance applications. Popular choices include BKR6EIX, BKR7EIX, and BKR8EIX.
  • Denso Iridium Power or Racing: Similar to NGK Iridium IX, offering a range of heat ratings suitable for various performance levels.

When using performance spark plugs, consult with a professional tuner or consult the manufacturer’s recommendations for proper heat range selection.

Spark Plug Wires

Maintenance Intervals: For NA and NB models with spark plug wires, it is recommended to replace them every 60,000 miles or sooner if signs of degradation or damage are present. The NC and ND models utilize a coil-on-plug design, which eliminates the need for spark plug wires.

Performance Spark Plug Wires: Upgrading to performance spark plug wires can improve engine response, efficiency, and overall performance. Here are some popular options:

  • Magnecor KV85 Competition (8.5mm): These high-performance wires offer superior heat resistance, better insulation, and reduced radio frequency interference (RFI).
  • NGK Premium Performance Wires: Designed for durability and performance, these wires offer low resistance and excellent insulation to ensure optimal current transfer.

Spark Plug Wire Installation Tips:

  • Inspect the wires for any signs of damage or wear before installation.
  • Apply a small amount of dielectric grease to the inside of the spark plug boots to prevent sticking and improve the electrical connection.
  • Route the wires properly to avoid contact with hot or moving parts, which can cause damage or premature wear.
  • Ensure the wires are fully seated on both the spark plug and ignition coil ends for a secure connection.

Firing Order

Don’t forget, the firing order changed. Due to the Miata’s wasted spark design, each set of two wires for each coil will fire at the same time. You can mix up wires from the same coil, but not wires that belong to cylinders on the other coil.

miata spark plug firing order

Choosing the correct spark plug for your Mazda Miata is crucial for optimal engine performance and longevity.

This guide has provided an overview of the different spark plugs available, along with maintenance intervals and options for performance enhancements.

Remember to follow the recommended maintenance schedule and consult a professional if you are unsure about spark plug selection or installation.

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“Every day that I can work on my Miata, drive my Miata, or even think about my Miata is a good day.”

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