Champion 791 C57YC 14mm Spark Plug, .750 Reach, 5/8 Hex, 57 Heat Range
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Q & A (1)
What's in the Box
Projected tip for gasoline. For Brodix and other aftermarket aluminum heads. For most magneto fired ignitions. Sprints and Late Models. 14mm plug, .750" reach, 5/8" hex.
Plug gap will depend on output of distributor and fuel being used. Most applications using methanol will be at .022" - .025". If your ignition sytem is a higher output, maybe able to go as wide as .030". Gas application should be .030" - .035". You should also consult manufacturer of distributor for their recommendations.
Champion Racing Series plugs include all the features of their conventional plugs, but are built with extreme engine conditions and durability in mind.
- Nickel Alloy Ground and Center Electrodes
- Copper Core Center Electrode Allows for Increased Conductivity and Heat Control
- 14mm, .750" reach, 5/8" hex
- Projected Core Nose
- Heat Range: Colder (57)
Item Details.750" Reach, 5/8" Hex
While 5/8" (16mm) and 13/16" are the two most common plug hex sizes, plugs can have a hex as small as 8mm or larger than 1".
If you're a tuner or engine builder in search of the perfect spark plug for your current project, pay special attention to the hex size required. Remember to take into consideration not only the diameter of the cylinder head, but also the added thickness of the plug socket needed for installation.
A spark plugs reach is calculated by the length of the threads. It is measured from the seat of the plug to the end of the threads.
It should be noted that the reach does not include the electrodes, or an extended metal shell. When custom-selecting a spark plug, the electrode length and projection should be included in the calculation when taking into consideration the clearance in the combustion chamber.
WARNING: Spark plugs with different seat types are NOT interchangeable.
- Spark plugs with a flat seat must be used in engines designed for a gasket seal.
- Spark plugs with a tapered seat must be used in engines designed for a tapered seal.
Use of an improper plug in an engine will result in engine damage.