HKS 50003-M40IL Spark Plug 8 for SUBARU EJ257 / EJ255

HKS M-Series spark plugs are high performance Iridium plugs designed to provide improved ignition performance, durability and anti-carbon build-up.

• 0.6mm Iridium Alloy Center Electrode
• Outer Electrode with Platinum Chip
• Short Type Outer Electrode (Anti-Vibration)
• Thermal Edge
• Spark Support Gap

M Series is recommended for reliable ignition, durability and anti-carbon buildup under high load.

The Iridium alloy is used because of its durability and reliability.  On an average plug, a narrow core typically shortens life span of plug but with the intense durability of iridium there is no sacrifice in any longevity.  With a high melting point of 2454 degrees C, opposed to the 1769 degrees C of white gold, the electrode can tolerate the high levels of compression and minor knocking without any deterioration. A nickel coating on the housing also prevents the spark plug from premature deterioration.  The Iridium plugs are available for multiple applications and offered in "colder" heat ranges of 7 and up and specifically for rotary, heat ranges of 9 and up are offered.

• Heat Range: NGK # 8
• Thread Size: 14mm × 26.5mm
• Wrench Size: 16mm