12 v conversion

I am completely stumped by the 12 v conversion on my case 310c that someon else did. Looking on this forum, I find several threads and articles that say in a 12 v conversion to keep the 6 v coil, attach negative coil terminal to distibuter, and a ballast resister is needed (several wiring schematics are available in the forum) My case 310 has a 12 v coil (12 v is printed on it, and printed on it is a message that says a resister is needed)', and the positive coil terminal is connected to the distributer. The Alternator is a 1 wire alternator. the battery is negative grounded. I wish I felt positive on how it should be set up. I found instructions on steiner tractor for conversion kits they have, they show 6 v coil with negative terminal connected to distributer. Any help would be greatly appreciated.

Just me, but if I was converting from 6 volts to 12 volts, I would use a 12 volt coil and a 12 volt condenser, as well as a 12V alternator. The only thing I would leave 6 volts is the starter, which shouldn't run long enough to hurt it at 12 volts. Just me.

I have 12 volt coils on all 12 volt gas engines with a resistor before the coil. Incoming power to the coil goes to the positive side of the coil with negative side of coil to distributor. My 310 loader tractor still has the generator.

thanks

thank you. I wish my 310 was still 6 v. I understand the 6 v set up. I have ssveral old 6 v vehicles, 48 case va, 50 dodge pickup, and others. They work just fine in all kinds of weather. I have never understood the need to convert.

I wonder if the positive coil connection to the distributer is the reason it has such a weak spark and runs so poorly? I guess I will switch it and see.

whoever did the conversion did sloppy work, just doesn't look to me like they knew what they were doinf.

(quoted from post at 09:35:02 12/05/17) thanks

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This topic comes up frequently about condensers. I have done hundreds of 6 tp 12 V conversions with no condenser changes. If you will take time to go to the YT mag site and look up a points and condenser kit for a VAC (6) V you will find the same kit listed for all models that use the same number distributor clear through the 631 (12) V distributor. The condenser works on the ground side of the coil and sees essentially the same conditions in either 6 or 12 V mode.

I agree with you on leaving 6V applications 6V. Only in some rare instances is a 12V conversion warranted. However, I do not think reversing polarity is gong to help a weak spark situation. Make sure the spark plug wires are real copper core, and that they do not say "Silicone" or "Radio Suppression", if they do replace them immediately. Also, the only spark plug I would use in your 310 are Autolite 3116, which are an extended tip, non-resistor plug.

Be aware that the 1 wire alternators need to be revved a bit when started to energize the field. I found that with an SC it needed around 1500 to start charging, which is hard up against the governor, nothing I like to do with a cold engine. My 1959 310B backhoe is factory 12 volt, where was the change? All of my conversions use the 3 wire alt, simple to wire, either with a diode kit, or what I like to is do if to wire off the hour meter or a separate oil pressure switch. I buy a switch (NAPA) that is normally open, but when closed with 10# of oil pressure completes the circuit and energizes the field. You can get them in what ever pressure range you want, either normally open or closed. Get the right one.

A 12v coil will have an internal resistance and measure 3 ohms across the + & - terminals while a 6v measures 1 1/2 ohms. Many 12v coils are actually 6v but are marked "use with external resistor". Advantage of the 6v w/external resister is the hotter spark during cranking due to the "R" terminal on starter solenoid bypassing the external resister.

thanks I have new wires coming from Steiner, along with new cap, condenser, and points.

thanks

thank you

There are 2 types of coils labeled for 12 volts. One is labeled ?12 volts use external resistor? and the other labeled ?12 volts, no external resistor required?. The first has about 1 1/2 ohms resistance across + an ? terminals of the coil, the second has about 3 ohms. The difference is in the wire used to wind the coils, there is no added resistor in series with the coil inside the can. You could use the ?external resistor required? coil on a 6 volt system and eliminate the resistor.

The purpose of the resistance is to limit current through points and coil to about 4 amps. With the external resistor limiting the current it divides the supply voltage across coil and resistor so you see 6 volts dropped across each one.

With positive ground the + terminal should go to the side of distributor, with negative ground the ? goes to distributor. The coil doesn?t care which way it is wired, the difference has to do with the spark plug. If the coil is wired to match battery polarity the plug will ?spit? the spark from center electrode to ground tab. If coil polarity is reversed the plug will ?suck? the spark from ground tab to center electrode. The plug is more efficient if it ?spits? rather than ?sucks? the spark.

There is no distinction between a 6 volt and 12 volt condenser. If you could find specs on a condenser you would find they are actually rated for several hundred volts.

If you understand a 6 volt system, you understand a 12 volt system. They work the same. Difference is in amount of resistance in circuit to limit coil/points current.

Positive or negative ground is like right hand or left hand threads on a bolt. With bolts the nuts turn in opposite directions, with battery system current flows in opposite directions. Positive or negative ground should work equally well if polarity sensitive components such as ammeter, coil, and charging system are all configured to match battery polarity.

Make sure you have good quality battery cables and connections on both ends of both cables are clean and tight.

(reply to post at 13:17:26 12/05/17)

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Interesting stuff, as I posted in an earlier discussion you can hold a lead pencil lead in the spark stream and observe the direction of spark flow by watching the orangeish flare off the lead of the pencil.

Using Ohms law you will find the current flow of the primary is appx 4 amps in either voltage setup and the condenser sees virtually the same operating conditions. Good Discussion!!!

Good discussion. Neat tip about the pencil, mEl. I'm gonna try that sometime. ..This is what I like about the Case folks.......same discussion on an other brand's board would begin simple enough and somehow turn in to an argument. Especially electrical.

Yes, the condensers are the same on 6 or 12V systems, but they need to be rated at much higher voltages than that. If you look at an old automotive oscilloscope in action, the primary spikes will run around 30V on a healthy system. One with an open (or disconnected) plug wire or even just a wide plug gap can easily exceed 50V. An ignition condenser should be rated 100V or better, but I doubt most of the ones you buy today are. Certainly the days of leaving the condenser in for 50,000 miles are over.

Thanks so much, this explination was very helpful

quote="rvirgil_KS"](quoted from post at 10:17:26 12/05/17) There are 2 types of coils labeled for 12 volts. One is labeled ?12 volts use external resistor? and the other labeled ?12 volts, no external resistor required?. The first has about 1 1/2 ohms resistance across + an ? terminals of the coil, the second has about 3 ohms. The difference is in the wire used to wind the coils, there is no added resistor in series with the coil inside the can. You could use the ?external resistor required? coil on a 6 volt system and eliminate the resistor.

The purpose of the resistance is to limit current through points and coil to about 4 amps. With the external resistor limiting the current it divides the supply voltage across coil and resistor so you see 6 volts dropped across each one.

With positive ground the + terminal should go to the side of distributor, with negative ground the ? goes to distributor. The coil doesn?t care which way it is wired, the difference has to do with the spark plug. If the coil is wired to match battery polarity the plug will ?spit? the spark from center electrode to ground tab. If coil polarity is reversed the plug will ?suck? the spark from ground tab to center electrode. The plug is more efficient if it ?spits? rather than ?sucks? the spark.

There is no distinction between a 6 volt and 12 volt condenser. If you could find specs on a condenser you would find they are actually rated for several hundred volts.

If you understand a 6 volt system, you understand a 12 volt system. They work the same. Difference is in amount of resistance in circuit to limit coil/points current.

Positive or negative ground is like right hand or left hand threads on a bolt. With bolts the nuts turn in opposite directions, with battery system current flows in opposite directions. Positive or negative ground should work equally well if polarity sensitive components such as ammeter, coil, and charging system are all configured to match battery polarity.

Make sure you have good quality battery cables and connections on both ends of both cables are clean and tight.[/quote]