Posted by Alan Bowes on February 01, 1998 at 11:45:16:
In Reply to: SPARK PLUGS posted by Thomas Kralovic on January 31, 1998 at 22:17:36:
Since the ignition isn't original, you can either rely on the experience of others, or you can use the following criteria for plug selection:
1) Obtain an original shielded plug (a used one is fine).
2) Find a new plug with the same thread length, reach, and heat range as the original plug, and use that as a starting point. This isn't hard. Just take the original plug down to an auto parts store and you can compare a few.
3) Carefully tune the engine to specs.
4) Run it for at least a few hundred miles, then pull the plugs and check their condition to make sure that they are running clean without burning. I won't go into a detailed explanation of analyzing plugs, since there are books that have close-up color pictures of various conditions and causes. Besides using the wrong heat range, mixture and timing can also affect spark plug condition.
Whatever you do, do NOT use a different thread length or reach than stock. You can, however, experiment with different heat ranges.
Alan