Wilsons Sandbox

There as been a lot of correspondence regarding various codes and heat ranges for sparkplugs but can someone clarify for me (and perhaps a few others) just what it all means? We have all heard comments like "you need to fit colder plugs for racing" or "if you are having trouble with plug fouling you need to fit hotter plugs" but what does this mean. Is a colder plug one with a lower heat value or one with a higher heat value as expressed in the chart provided by Madhu. Ie, is a plug with a heat value of 200 considered hotter or colder than a plug with a heat value of 175? Maurice Paton TC9357 [Non-text portions of this message have been removed]

Dear Maurice Paton, In our TC Instruction Manual it is recommended to use Champion L-10-S (14mm) spark plug. Those days champion list shows only three or four sparkplugs. L-8 has 145, L-10 has 225, and L-10-S 240 heat value. Madhu