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 .
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 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.
Summary: Always have what I need!
Yes, I recommend this product.
Summary: They fit well and made indexing the spark plugs a breeze. I will order more so I will have them on hand for my future projects. The color coding makes it easy to keep the different thicknesses from getting mixed up.
Yes, I recommend this product.
Summary: They work great on indexing your spark plugs the only thing is that if you over tighten them they get crushed and you have to change them out to a new one and start over again. Other than that I would recommend this product to anyone who is running a domed piston.
Yes, I recommend this product.
Summary: can't get any easier to install.
Yes, I recommend this product.
Summary: Free hp!
Pros: Easy To Install