Outwardly the appearance of a spark plug has not changed. But internally there have been many improvements.


Although a current spark plug looks very similar to a spark plug from 50 years ago, changes have occurred in its materials and construction. These changes have increased the useful life of the spark plug, minimizing the number of “tune ups” a vehicle might need. The changes, however, have also increased the price of the product. One change that might account for this price increase is the use of refractory metals in the current products. But does the amount of the costly precious metals really account for the increase in price?