"Short Wave Sportfishing" wrote in message
...
On Mon, 23 Feb 2004 20:10:04 GMT, "Geoff 93 RRC"
wrote:

If you are looking for power and clean combustion, a hotter plug is
always the best choice

Actually, the heat range of the plug only refers to the plugs ability to
transfer heat from the plug to the head. A hot plug is one that that the
tip retains more heat, a cold plug transfers heat quickly. When driving,
the tips of the spark plugs are heated to incandescence. The heat must
travel from the tip through the shell and ultimately into the water jacket
of the cooling system. If the plug is too cold it will foul, if its too hot
you will get detonation, that is, the fuel will ignite before the timed
spark -- and you can blown a hole through the piston!

The octane rating of the fuel and compression ratio will determine the
correct heat range plug to use. Unless you have modified the engine, stick
to the manufacturers recommendation.

Rich