Spark Plug Indexing Washers

$7.50
 /set

$7.50
 /set

  One of the simplest ways to improve the combustion in your engine is to index the spark plugs. Indexing the plugs ensures that the gap is facing the combustion chamber. If the stem of the ground electrode is facing into the chamber, then the spark is shrouded from the majority of the fuel/air mixture (photo #4). When the stem of the ground electrode is facing away from the chamber, the fuel/air mixture will burn more quickly and completely (#2, #3). 
  The easiest way to accomplish this is to mark the insulator or metal base with a felt tip marker showing the location of the ground electrode stem. Install the plugs and torque to 10 ft-lbs. Ideally, the gap will be facing toward the intake valve or centered between the intake and exhaust valves (#2, #3). You want to be able to see your mark on the plug (#1). It's best to have the line fall between the two head bolts. If they are not within this range, try swapping the plugs from the front head to the rear head and vise versa, and they will usually come pretty close. We sell indexing washers in 3 thicknesses for both the 12mm and 14mm plugs, but they are rarely necessary. While some people may notice a difference in their engine’s performance, most will not.  As a general rule, we recommend replacing the spark plugs with new standard plugs every 5,000 miles.

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