What spark plugs are you currently using?

DannL

DannL

Senior Member
Yeah, consider this a poll. Give the brand and part number of your plugs. Are you happy with them?
 
Running original 1930's vintage Champion 3X plugs. They run great. Wouldn't consider anything else!!!
 
rfitzpatrick said:
What does it mean when you said they're to hot/cold plz. I really don't understand.
Thanks
Click to expand...

Spark plug heat range is the measure of how fast the spark plug tip dissipates combustion heat. It must do this in a precise and controlled manner so the spark plug will:
Stay cool enough to avoid pre-ignition and/or electrode destruction due to detonation.
Run hot enough to burn off combustion deposits that would otherwise collect on the sparkplug insulator tip and cause fouling, that leads to misfire.
Adapt to specific engine characteristics and widely varying driving/load conditions.

"Hot" spark plugs remove heat from the combustion area relatively slowly. They have a longer insulator tip and they achieve a temperature higher than the deposition zone relatively fast.
"Cold" spark plugs feature a relatively short insulator tip and they remove heat from the combustion area quite fast, in order to avoid advanced ignitions.
The choice of a proper heat range is very important. But even a spark plug featuring a properly selected heat range, is influenced by the processes of fouling and self-cleaning of the insulator tip. The setting of combustion deposits on the insulator tip is caused by an imperfect combustion due to a "rich" air/fuel mixture. On the other hand, the combustion deposits previously set will burn if the insulator tip temperature rises above 475 °C.
Zones of spark plug fouling and self-cleaning zone depending on the air/fuel ratio and on the spark plug insulator tip temperature.

https://www.briskusa.com/spark_plug_cross_reference_heat_range_chart
 
rfitzpatrick said:
What does it mean when you said they're to hot/cold plz. I really don't understand.
Thanks
Click to expand...

Internal combustion engines run at different temperatures. If more specific power, the combustion chamber gets hoter temperature. (Very simplified explanation.)

Simply explained: The hotter engine burns needs the colder the ignition plugs must be. (This interpretation is unfortunately not uniform; in Japan, the standard designation, for example, vice versa. I do not know USA.

Rule of thumb: Hot engine need 'cold' plug. Cold engine 'hot' plug.

For me, the global standardization of of the interpretatin "a plug is hot or cold" is difficult to explain.


If the spark plug does not get hot enough, it will become sooty. If it overheats, there is dangerous high speed knocking!
 
3077 Autolite. Been using them for probably 30 years, wish I could still find them.

There was a recent similar thread.
 
The current 3X’s I’ve seen have dual grounds (I think that is what they are called). Is that an improvement/. Are they good for our Model A’s?
 
I have been running original champion 3X`s in my Victoria for over 25 years. and I also run repro, 3X`s in the 160A. with unleaded fuel the plugs last a lot longer, the 16Y`s are to cold for me.
 
Boy, Am I red faced. 😱. I was mistaken. The online photos have a shadow which makes it appear as though there is a second ground. I apologize for the oversight.
 
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