NGK Plug cross over

[adam1961]

For those of you that use NGK plugs….doe you use B7S or B8S in place of Champion J4J –> J4C? I use B6S in my bigger motors with good results, but I see that both the B7S and B8S are listed as the interchange for the "4" heat range champions.

[joecb]

BM7A seem to be good in my Zephers. These NGK plugs are perfect for applications where the plus(s) are enclosed in a metal shroud as in the Zephyr because of two features. One, the porcelain body (outer) is shorter than the Champion, less likely to come in close proximity to the metal shroud and , two, the terminal is threaded to accept the old style ring terminal. Just be aware that the stud is metric 4mm- .7 so your original nuts will not fit.

Joe B

[Mumbles]

The NGK B8S are closest to a J4J and are a good starting point for motors requiring the J4J. B6S replace the J6J.

One thing to remember about the NGK’s is their numbering system. It is the opposite of Champion and the higher the number, the colder the plug.

[Pete]

FYI the NGK cross overs to other plugs are approximate and the correct cross over plug needs to be determined for each application by the usual measurements and observations associated with plugs used. You can only be sure of the characteristics of NGK within their own brand like wise with other brands.

[garry-in-michigan]

zul8tr stated;

quote :

,,, Cross overs to other plugs are approximate and the correct cross over plug needs to be determined for each application

That is also true of the factory recomendations. They are aproximations and may change with temperature and load. . . 😉

[Author]

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