Product Summary

Universal Fit, .53" Inside Diameter

  • For use on all 14mm tapered seat spark plugs
  • Orients the spark plug electrode opening in the combustion chamber towards intake valve
  • Ten stamped copper washers each of three thicknesses provide ability to rotate plug up to 315 degrees.
  • Washer thicknesses are 0.010", 0.021", and 0.032"
  • Provides an easy way to index your spark plugs for best performance

Key Specs

MFG. Part #54571900
BrandSpeedway Motors

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Speedway Motors 54571900 Details

  • Fits all 14mm spark plugs with a tapered seat
  • Made from stamped copper material for proper sealing and heat transfer
  • Indexing spark plugs rotates the electrode ground strap for more complete combustion
  • Can be reused when new plugs are installed if not overtightened
  • Includes three thicknesses with 10 washers in each size (30 total per package)

Quickly Position Your Spark Plugs for Best Performance with Easy to Use Indexing Washers

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 back side of the electrode (ground strap) towards the nearest cylinder wall, away from the middle of the chamber. This helps to unshroud the spark kernel and face it towards the intake valve. Due to manufacturing processes, there is no guarantee the threads are positioned the same on any two spark 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. Learn more about performance spark plugs in our Toolbox article.

Indexing spark plugs is quick and easy to do, taking nothing more than a set of indexing washers, a marker, and a little time to line things up. These indexing washers are designed for tapered seat 14mm spark plugs only (we do offer 14mm flat gasket seat indexing washers as well). These indexing washers come in three thicknesses, which allow the spark plug to be indexed 105, 210, or 315 degrees of rotation from their non-washer seated position. You can tailor both the position and depth of the electrode using these washers. The kit includes ten (10) copper washers of each thickness (0.010", 0.021" and 0.032"), which may be reused if not over tightened.

Speedway Motors 54571900 Specifications

MFG. Part #54571900
BrandSpeedway Motors
Speedway Motors Catalog Part #545-71900
Spark Plug Seat StyleTapered
Inside Diameter.53"
Outside Diameter.69"
Material TypeCopper
Sold in QuantitySet