Son has a front mount that has been converted to 12 volts. It has 2 resistors before the coil but it burns the points in about 2 hours of running.

[teddy52food]

Son has a front mount that has been converted to 12 volts. It has 2 resistors before the coil but it burns the points in about 2 hours of running. When he turns on the ign switch the ampmeter shows a 10 amp discharge. We changed one resistor to a higher value but it still shows 10 amps discharge. Part of this would be going to the alternator . What resistor should we be looking for?

 

[Jim L WA]

Really not enough information.
1. is the OEM ballast resister still in the circuit? The one mounted on the back of the dash.
2. What is the resistance of the the coil from the top of the coil to the pig tail on the bottom?
3. Is this an old conversion that used to work or a new conversion?
To draw 10 amps when the key is turned on sounds like it's wired wrong or there is a short somewhere.

 

[JMOR]

Son has a front mount that has been converted to 12 volts. It has 2 resistors before the coil but it burns the points in about 2 hours of running. When he turns on the ign switch the ampmeter shows a 10 amp discharge. We changed one resistor to a higher value but it still shows 10 amps discharge. Part of this would be going to the alternator . What resistor should we be looking for?

A value that will limit coil current to 3 1/2 to 4 amperes when points closed and not running.

 

[deanostoybox]

Son has a front mount that has been converted to 12 volts. It has 2 resistors before the coil but it burns the points in about 2 hours of running. When he turns on the ign switch the ampmeter shows a 10 amp discharge. We changed one resistor to a higher value but it still shows 10 amps discharge. Part of this would be going to the alternator . What resistor should we be looking for?

IF it is a three wire alternator with a diode going to the excite terminal (#1) it will pull 4-5 amps key on motor not running.

Front mount in normal operation will pull 5+ for a few seconds, dropping to 4A, and if left on in static (not running or cranking) will reach an equilibrium at about 2.5A.

If points are burning in 2 hours running time, I would be looking at the condenser (points pitting).

 

[teddy52food]

It had 2 long white resistors & I changed one with one I had that had more resistance. It was converted when he got it & always had problems. Condenser checks out to be good with a good condenser tester. If he still has trouble I will get the original one for behind the dash. This site shows they have them. Or go to a 12 volt coil which they have also. Thanks for the replies.

 

[wore out]

It had 2 long white resistors & I changed one with one I had that had more resistance. It was converted when he got it & always had problems. Condenser checks out to be good with a good condenser tester. If he still has trouble I will get the original one for behind the dash. This site shows they have them. Or go to a 12 volt coil which they have also. Thanks for the replies.

Even with a "12 Volt" front-mount coil you need to keep the dash-mounted OEM ballast resistor in the circuit.

 

[Jim L WA]

It had 2 long white resistors & I changed one with one I had that had more resistance. It was converted when he got it & always had problems. Condenser checks out to be good with a good condenser tester. If he still has trouble I will get the original one for behind the dash. This site shows they have them. Or go to a 12 volt coil which they have also. Thanks for the replies.

That condenser may not test good after it gets warm. They don't cost much, but are questionable out of the box.
If you are going to try a new coil, go with a 12 volt one and eliminate the external resisters.

 

[teddy52food]

Even with a "12 Volt" front-mount coil you need to keep the dash-mounted OEM ballast resistor in the circuit.

That is good to know. Thanks.

 

[wore out]

That condenser may not test good after it gets warm. They don't cost much, but are questionable out of the box.
If you are going to try a new coil, go with a 12 volt one and eliminate the external resisters.

ONE MORE TIME... Even with a "12 Volt" front-mount coil you need to keep the dash-mounted OEM ballast resistor in the circuit."

 

[Tony in SD]

Are the resistors in series or parallel? That will make a huge difference In the resultant resistance.

 

[teddy52food]

Are the resistors in series or parallel? That will make a huge difference In the resultant resistance.

I would say series as it goes from one to the other.

 

[Jim L WA]

ONE MORE TIME... Even with a "12 Volt" front-mount coil you need to keep the dash-mounted OEM ballast resistor in the circuit."

wore out, I am very aware of that. I should have been more specific, but teddy52food said that it had two resisters is the circuit. I was picturing two ceramic ones, but maybe one of the two he was referring to was the OEM one.