Coils--I'm confused

[Don G 1947]

I tried searching the archives for this answer, but gave up after looking at about 100 threads.

I running a standard 6 volt positive ground system. Can I use a 12 volt coil or do I need a 6 volt coil? I thought it didn't make any difference, but some of the posts seem to imply that it does makes a difference.

Thanks,

Don

[Bob_Koch]

6 volt is needed.

ECH IC7 is part number from a NAPA store

UC-14 is part number for SMP (Standard Motor Products) most stores like Autozone or O'reilly should be able to get it.

[greg g]

Most coils for point style are interchangable, unless they are labeled as bing iternally resisted. when the switch was made from 6 to 12v, it was noted that 12v sent throug the coils was shortening their lives. Manufacturers adress it in a couple ways, the balast resister, common to Mopars, which is basically a ceamic mounted coil of wire. the resisted wire like a couple others used , and the internally resisted coil which I think were basically used by GM. In all cases they droped the 12v to 8 or 9 which made the coils windings happy and gave a good spark. So basically any coil that is not internally resisted will be happy on 6V. Coventional wisdom says the positive ground system should have the coil negative conected to the neg and the pos terminal connected to the points and thus to ground. So for the purposes of mounting something for gettig an engine to start and runn for testing purposes just about any standard round coil not lavbles as resisted will fit the bill. On a 12 V system a digital meter on the wire feding the coil will tell you whether you need a resister in place. as stated the unresisted coil is happiest on 6/9 volts.

[Don G 1947]

Thank you for your replies. When I dig out of this snow I will head out to pick up a coil.

Don