Product Summary

Universal Fit, .53" Inside Diameter

  • For use on all 14 mm spark plugs
  • For indexing the orientation of the spark plug electrode in the combustion chamber
  • Ten washers each of three thicknesses, stamped copper
  • 30 per package
  • Includes detailed instructions

Key Specs

MFG. Part #54571900
Spark Plug Seat StyleTapered
Inside Diameter.53"
Outside Diameter.69"
Material TypeCopper

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  • Fits all 14mm spark plugs with a tapered seat
  • Made from stamped copper material for proper sealing and heat transfer
  • Can be reused if not overtightened
  • Includes 3 thicknesses with 10 washers in each size (30 total per package)

If extracting maximum horsepower & torque is your goal, consider adding these spark plug indexing washers at your next tune up. Indexing shims allow you to properly orient the spark plug electrode within the combustion chamber of the cylinder head. Proper electrode orientation ensures maximum efficiency (complete burn) and increases the speed at which the fuel is burned (more power).

The object of indexing spark plugs is to position the electrode (ground strap) towards the nearest cylinder wall, away from the middle of the chamber. This helps to unshroud the spark kernel. Due to manufacturing processes, there is no guarantee the threads are positioned the same on any two plugs, or that the threads in the cylinder head are consistent from chamber to chamber. In other words, chances are if you screw a plug into the head, it won't put the electrode in the same position as all the others.

These washers come in varying thicknesses, allowing you to tailor both the position and depth of the electrode. Package contains ten (10) copper washers of each thickness (0.30mm, 0.50mm and 0.80mm), which may be reused if not over tightened.



MFG. Part #54571900
BrandSpeedway Motors
Spark Plug Seat StyleTapered
Inside Diameter.53"
Outside Diameter.69"
Material TypeCopper
Sold in QuantitySet