autolite 24’s?

A spark plug is said to be "hot" if it is a better heat insulator, keeping more heat in the tip of the spark plug. A spark plug is said to be "cold" if it can conduct more heat out of the spark plug tip and lower the tip's temperature. Whether a spark plug is "hot" or "cold" is known as the heat range of the spark plug. The heat range of a spark plug is typically specified as a number, with some manufacturers using ascending numbers for hotter plugs and others doing the opposite, using descending numbers for hotter plugs.

The heat range of a spark plug (i.e. in scientific terms its thermal conductivity characteristics) is affected by the construction of the spark plug: the types of materials used, the length of insulator and the surface area of the plug exposed within the combustion chamber. For normal use, the selection of a spark plug heat range is a balance between keeping the tip hot enough at idle to prevent fouling and cold enough at maximum power to prevent pre-ignition leading to engine knocking. By examining "hotter" and "cooler" spark plugs of the same manufacturer side by side, the principle involved can be very clearly seen; the cooler plugs have more substantial ceramic insulators filling the gap between the center electrode and the shell, effectively carrying off the heat, while the hotter plugs have less ceramic material, so that the tip is more isolated from the body of the plug and retains heat better.

Heat from the combustion chamber escapes through the exhaust gases, the side walls of the cylinder and the spark plug itself. The heat range of a spark plug has only a minute effect on combustion chamber and overall engine temperature. A cold plug will not materially cool down an engine's running temperature. (Too hot of a plug may, however, indirectly lead to a runaway pre-ignition condition that can increase engine temperature.) Rather, the main effect of a "hot" or "cold" plug is to affect the temperature of the tip of the spark plug.

wouldnt hurt anything to do it that way....id go with the 25's..

Gottaski, if you buy autolite app24's they are warrantied for life buy one time replace when burned up for free. No questions asked.

ryanandrews wrote: what do they cost per plug???...full life time replacement??...gotta be a catch..

Theyre double platinum... not cheap. $5 or 6 a piece (at least).

never had a problem exchanging them for new ones. I think I pay $2.50 a plug, yeah that sounds right off the top of my head. Just under $22 for 8 of them. I get garage discount though, not sure what list price is.

yea that seems like a huge backdoor discount, i mean garage door!!........standard plus are just under 20 for 8 of them

I think the regular 24's I pay just over a buck a piece for them. The regulars are not marked up as high. I don't usually get them unless they are going in something I am selling.