case vac-14 12 volt conversion

[AdamC3825]

I just picked up cas vac-14 the other day and i was wondering if anyone had a 12 volt wiring diagram or how different it is from a 6volt system because mine i missing alot of wiring and has been previously been converted to 12 volt not done very well so it has a 12 volt alternator and coil

 

[Janicholson]

There are differences. First is the polarity of the coil. The coils negative small terminal should connect to the distributor, matching the polarity of the alternator. The amp gauge should read negative when it is not running and the lights are switched on, and positive when the engine is running just after starting. Then it should drift back toward zero at the battery is fully charged. A true 12v coil will be wound internally to run at 14+ volts with no ceramic ballast resistor. A coil requiring a resistor will be labeled as such. a coil requiring a resistor will have an ohm reading of 1.2 to 1.4 ohms. a true 12v coil will measure in the 3 to 4 ohm region. These are measured with one wire disconnected from the small terminal, and measured across those small terminals. The alternator brand and number are needed to determine what needs to be wired to which terminals, so we need to know that, a picture will help (see the bottom of the screen to load an image. Wire sizes from 6 volt are good to go). If replaced, use the same gauge wire. Use terminals that solder on, and then use shrink tubing to seal that connection. They are simple and a diagram should be in your repair manual (YT sells them). Modify it as described above. Lamps should be changed to 12v equivalent, or LED for headlights. Jim

 

[Hemmjo]

Just a word of caution. (well, more than one word)

A volt meter is superior to the amp meter when switching to alternator. Most modern alternators will provide much more AMP output than the old generator/regulator set-up. The wire in your harness will not carry the increased current without risking over heating. ALL of the current, except to the starter, passes through the wires to the AMP meter. If your battery is low, and you start pushing 40-50-60 amps back to your battery with your new alternator, you may easily damage your wire harness. Check the wire size running to your AMP meter, if it is #10, you are safe up to 30amps. Most tractors I have seen only have meters that read 20AMPs.

A volt meter will tell you much more about the health of your charging system. The volt meter does not use much current it can use the same wire your amp meter did but would only need much smaller wire. It just connects to the ignition side of the switch and to ground.

Just something to consider.

John

 

[AdamC3825]

I just ordered a 12v coil with internal resistor and i was wondering if it would still b negative ground? Does it wirw up the same way a 6volt would other then the alternator and stuff because i need to make a whole new harness

 

[Hemmjo]

Does not matter to the coil POS or NEG ground. Just hook + on the coil to the wire heading to the + on the battery. Connect the - on the coil to the wire leading to the - on the battery.

On a POS ground circuit the points are +. On a NEG ground circuit the points are -.

John

 

[AdamC3825]

Well I hooked up the coil and I m not getting any spark i have power to the wire going into my distributor but no spark

 

[Hemmjo]

I wonder if your condenser does not like the 12V you are feeding it now? It may have shorted out if it was going bad anyway. Try new 12V condenser.

 

[BarnyardEngineering]

Take the coil wire off the distributor cap and place it near the engine block. Remove the distributor cap and dust cover. Rotate the engine until the points are closed. Now you can "flick" the points with any convenient flicking tool, and generate a spark at will.

It's a great troubleshooting method that lets you test the coil, points, and condenser. If you can get spark doing this, at worst you've narrowed it down to the rotor, cap, and wires. At best, everything will work.

 

[AdamC3825]

It doesn t have points it has the updated magnetron ignition from what I understand