HOTTER DOWN TO COLDER - Spark Plugs

Now this is the kind of info i like to see on the Ford Barn. Thanks for posting this Larry and all the other peoples input.
 
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The W18 plug you purchased is a tad hotter than the C16C you had in there, and a tad hotter than the stock Model A plug (per Larry's information).

If you have a stock compression head, you are probably OK with the hotter W18. If you have any fuel or oil contamination on your plugs, where they would tend to foul, then the slightly hotter plug might help keep it firing better longer.
 
Does anyone know what a Champion 3 plug is for ??.. I have three of them & they came out of the 30-31 style original base plug..
 
This great info it must have taken a while to compile it. A copy is going into my tech notebook
Thanks
 
There is a general misconception about spark plug heat range. The heat range refers to the ability of the plug design to conduct heat away from the total assembly especially including the exposed section in the combustion chamber it does NOT refer to the heat of the spark. The spark is controlled by the magneto or coil and it is always the same regardless of what spark plug is installed. Now keep in mind RPM, compression ratio and wiring can effect spark, but not the heat range of the spark plug. Does this make sense to you? Please ask questions if not. Thanks for your time
 
6201241hg said:
There is a general misconception about spark plug heat range. The heat range refers to the ability of the plug design to conduct heat away from the total assembly especially including the exposed section in the combustion chamber it does NOT refer to the heat of the spark. The spark is controlled by the magneto or coil and it is always the same regardless of what spark plug is installed. Now keep in mind RPM, compression ratio and wiring can effect spark, but not the heat range of the spark plug. Does this make sense to you? Please ask questions if not. Thanks for your time
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Makes perfect sense to me. And the temperature of the nose of the plug will affect if fuel or oil deposits build up in the plug to foul it or not. If you are burning oil or your carb mixture is rich, you want to run a hotter plug to keep the electrodes clean longer. But you don't want too hot of a plug or you will promote engine knock and other bad things when running hard (high speed, heavy load).

So what you really need to do is test drive different plugs, compare their performance, and then look at them (read them) after some miles to see if they are fouling too quickly or running too hot.
 
Kirby1374 said:
I just purchased a set of W18's. I have c16c's in the motor now. the W18's are bigger in size. Did I get the right plugs?
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I switched to W18 plugs more than 1,000 miles ago after running W16Y plugs. The engine runs better. And I would add that an article in Model A Times (Spring, 2009) This article says the W18 is hotter than the W16Y, and that W18 plugs may be a good choice for engines run rich and burn oil. Mine doesn't burn oil, but it does run a bit on the rich side. If you use an air filter, this may cause the car to run rich.
 
i just came back from a auction that had tons of old car parts and I picked up in a box of stuff a full new box of C-16C plugs and a new box of D-14 champion plugs. I can see from other postings that the C-16C's fit Model A, but what about the D-14's. What fits 1935 Flathead?
You guys are a great resource of information.
Thanks,
Jerry:)
 
C16C C4. W18 my choices, I have a 5.5 Snyder head with a stock rebuilt engine and the C4s are running a nice light tan. All champion plugs. Good luck
 
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