The Mazda RX8 rotary engine uses a unique combination of leading and trailing spark plugs. The OEM parts supplied by Mazda are NGK Laser Iridium, part numbers RE8C-L & RE9B-T. These plugs are supplied pre-gapped by 0.48" / 1.2mm ready to install. They are so called due to the unique laser welded center electrode.

Experiencing hot start ignition problems or flooding?

TIP: Switching your standard RX8 leading spark plugs for a warmer heat grade such as RE7C-L will often solve hot start ignition, flooding and stalling problems commonly associated with the 13B-MSP Renesis engine.

A full set these warmer grade RX8 spark plugs can be found at JP4mance Tuning Parts - Price: £64.95 inc vat!

RX8 Spark Plug & Leads Install Guide

1. Jack the car up and remove the near side front wheel. Make sure the car is nice and secure on a frame before you climb under - safety first!

2. You should now be able to reach the spark plug wires connected to the rear rotor - pull them off one at a time, and make a note of which new lead replaces it by comparing their lengths old for new. No two leads are the same length so by doing it this way, you can't go far wrong.

3. Using a wrench with a 5/8" socket, turn the spark plugs counter clockwise until lose enough to turn by hand. If you have a 12" ratchet extension to hand this will make life easier.

4. Be sure to make a note of which plug came out first. The plug part number marked with a 'T' is the trailing plug, while the plug marked with the letter 'L' is the leading plug. The letters T & L are some times marked on the metal work too.

TIP: It may be worth checking the condition of the ignition coil packs whilst you are down there, especially if you have been experiencing ignition problems or loss of power recently. White heat spots found on the underside of each coil would suggest that it's earthing out on the inner casing. Lack of power to the spark plugs will then result in unburnt fuel washing oil away from the rotors resulting in engine damage. Excess unburnt fuel will also rapidly corrode the exhaust, catalytic converter and oxygen sensors located before and after the cat.

If the coil packs need changing, make sure you buy the genuine Mazda item and that you are buying the REVISED version, as fitted to later RX8 models from the factory to combat this common fault.

A full set of these genuine Mazda coil packs (Revision C) can be found at JP4mance.co.uk. Price - just £249 inc vat!

5. Coat each new spark plug with some anti-seize before replacing into the correct location. Make sure the correct wires are firmly in place.

6. To gain access to the front rotor, remove the bolt and washer that secures the rubber splash guards in place - be gentle, it breaks easily!

7. Now follow step 2 - step 5 above to replace the front rotor spark plugs, and then work in reverse order making sure everything is fitted securely before turning the ignition.

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