Another 12V Question

JCinKY · Nov 19, 2012

So I will be replacing the shotty wiring on my newest project. 8n front mount already converted, still has 6v coil. It has a resistor inline to the coil but I have no idea of the rating. How do I measure internal coil resistance? What is the "most common" resistor I'll need?

It doesn't have the original ballast so I will have to locate. I understand I may need anywhere from a 3.6-4.0 ohm resistor, but don't know where to start. In some of JMORs diagrams I notice he uses a terminal block instead of the ballast. Could I up the line resistor and forget the ballast??? Sorry, lots of q's. Thanks for all the help.

Jeff

Dell (WA) · Nov 19, 2012

Jeff........both the original 6-volt squarecan coil and the modern 12V-square can coil need the "infamous ballast resistor" (mounted on the backside of the dash panel under the ammeter) NO ARGUE!!! To use the original 6-volt square can coil on 12-volts, you also need a 12-to-6V converting resistor of 2.5-ohms and 50-watts. (these are electrical specifications) Most tractor parts stores do NOT sell the correct 2.5-ohm converting resistor. They try to sell you the 8NE10306 (YT claims it is 3-ohms, which is close) It will work but causes weaker sparkies. One of the reasons to convert to 12V is faster starting hotter sparkies and quicker spinning of the 6-volt starter motor. (NO, 12-volts does NOT hurt yer 6-volt starter motor) Remember to also change yer headlites to 12-volt bulbs. Yer distributor points and condenser are good for about 200-volts so no worry there. .......Dell, a 12-volt advocate that knows 8-ways to convert to 12-volts and they all work the first time

JMOR · Nov 19, 2012

(quoted from post at 22:26:25 11/19/12) So I will be replacing the shotty wiring on my newest project. 8n front mount already converted, still has 6v coil. It has a resistor inline to the coil but I have no idea of the rating. How do I measure internal coil resistance? What is the "most common" resistor I'll need?

It doesn't have the original ballast so I will have to locate. I understand I may need anywhere from a 3.6-4.0 ohm resistor, but don't know where to start. In some of JMORs diagrams I notice he uses a terminal block instead of the ballast. Could I up the line resistor and forget the ballast??? Sorry, lots of q's. Thanks for all the help.

Jeff

f you don't know the coil's primary resistance, then how do you know that it is a 6v coil? 6 & 12 coils look the same.
In the end, what you really need is a coil plus resistor that yields about 4 amperes of steady state coil current. It will average much less running, but no one cares.

NOXJohn · Nov 20, 2012

In my opinion the best thing to do when converting a front mount to 12 volts is to make the modifications to use a real 12 volt oil filled no resister needed round can coil. The second best is to use the original ballast resister with a 12 volt square can front mounted coil.

JCinKY · Nov 20, 2012

I think I will use what I have first and see what happens. Not a big deal to put in a 12v coil if all else fails.

JMOR, I'm 51% sure its a 6v coil since it has a resistor inline, but I can't tell the rating and I will be replacing the entire harness so I know it is correct. I will check coil resistance this weekend and find the appropriate additional resistor.

Dell, I will be locating the original ballast resistor and wiring it per JMOR's diagrams.

Thanks for all the help. I'll update you guys this weekend when shes wired up.

souNdguy · Nov 20, 2012

either get a 2.5 ohm coil ( 12v square type ).. and an oem ressitor.. os as Jmor said. expirement with ressitro values till you eventually nail it.

Another 12V Question

JCinKY

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Dell (WA)

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JMOR

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NOXJohn

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JCinKY

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souNdguy

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