spark plugs after going to 12V

[Scott52]

First, I am 69 (Brain starting to slow) and have never converted a 6 volt system to 12V. That means the part book components work. I have a 48 Dodge Power Wagon that uses an original generator and 6v system. The 52 Ford 8BA is being converted to 12 Volts with 5th Avenue 12V Alternator (Randy Rundle) and also Charlie NY SBC distributor. Rundle suggests a couple of 12Volt coils. What about the spark plugs. I have original cast iron heads. Not sure which plugs to use. Is there a difference between 6V and 12V plugs or does the coil used send out the proper firing voltage to the standard plug.

[marko39]

Plugs shouldn’t know the difference.

[fortyonerag]

You do not have to change plugs for a 12V conversion.

While many items need to be changed for a 12V conversion, spark plugs are not one of them.

[JayChicago]

Originally Posted by Scott52

or does the coil used send out the proper firing voltage to the standard plug.

Yes. That's the explanation. The coil used after converting to 12 volt is different than 6 volt.

[Scott52]

Thanks, my brain feels a little better. now I can take my nap in peace!

[Tim Ayers]

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Not sure what plugs are in there now, but NGK BL4’s work really well

[TomT/Williamsburg]

I agree with Tim - they last the longest and can go through several clean and recap cycles ….

[Scott52]

I can't find NGK BL4, even on NGKs website. I do see B4L. to be clear is that the NGK plugs you were referring to?

[Tim Ayers]

Originally Posted by Scott52

I can't find NGK BL4, even on NGKs website. I do see B4L. to be clear is that the NGK plugs you were referring to?

Yes, sorry. I mixed up the letters up while typing. B4L's. Get them from Rock Auto. Best price around.

[Steve in Denver]

Just make sure your new plugs are the same thread length as the old ones. Long ones don't work well in heads that require short plugs. My mechanic hopes to have time to tear my motor down this coming week to see how bad I damaged it by having plugs that were 1/8" too long.

[Lawson Cox]

Originally Posted by Steve in Denver

Just make sure your new plugs are the same thread length as the old ones. Long ones don't work well in heads that require short plugs. My mechanic hopes to have time to tear my motor down this coming week to see how bad I damaged it by having plugs that were 1/8" too long.

Oh, shucks, that sucks.

[Ol' Ron]

The amount of voltage the plug sees, depends on the compression. The higher the pressure the higher the voltage. So just because your system may be able to send more voltage doesn't mean it will. Stock plugs should work just fine.
Gramps

[V8COOPMAN]

Originally Posted by Ol' Ron

The amount of voltage the plug sees, depends on the compression. The higher the pressure the higher the voltage. So just because your system may be able to send more voltage doesn't mean it will. Stock plugs should work just fine.
Gramps

Dependent upon the maximum voltage that a particular coil is CAPABLE of supplying, that coil will only supply a voltage level that is necessary to fire any particular plug, with considerations of cylinder pressures, electrode gap, engine load, plug wire choice, and likely a few other factors, as Ol' Ron has alluded to above. In other words, just because you're running that "40,000 Volt Super Mega-Sparkulator Racing Coil", that coil may only be delivering a paltry 12k volts to your crab distributor for that leisurely Sunday ride to get ice cream cones. Coop

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