Help on Wiring case SC 1952

The wiring was never right on this tractor can anyone help steer me right the pressure switch was not connected and the rest you can see in the pictures. Note: No head or tail lights to hook up. Id be thankful for any insight I have no clue about wiring so keep it simple
Thanks Byron

From what I can see from your pictures your wiring is electrically correct.

What brand alternator are you using? Doesn't look like the commonly used Delco. Is it a one wire configuration? Alternator case should ground through the mount, so do alternator instructions call for an extra ground wire?

One possibility for the oil pressure switch is that it was used to turn on a previous Delco 3 wire alternator. One side of pressure switch to switched side of on/off switch, and other side of pressure switch to #1 pin of 2 pin plug on alternator. Makes no difference which way the pressure switch is connected.

With out some form of isolation (switch, indicator light, resistor, or diode) there may be feed back from #1 pin of alternator to output of ignition switch to coil that will cause the engine to continue to run when the ignition switch is turned off.

Your alternator should be negative ground and -- post on coil should go to distributor.

I'm sure the pressure switch is for the alt, I use the same switch on my 2 SCs. The only other option would be a later added hour meter. There is no visible resistor between the coil and the dist. With 12 volts that is mandatory. Your coil may have an internal resistor, and is usually marked if it does. If you don't know, be sure and check the voltage at the - or dis post with the ign switch closed. Should be 4 or 5 volts below battery voltage. This is to protect the breaker points. 6 volt systems did not need resistors. Just as an aside, I had trouble with 1 wire alt on my SCs because the engine would have to be reved up against the governor to get the alt to kick in. That's around 1600 rpm and I sure didn't like revving a cold engine up to get the battery charging

(quoted from post at 03:19:24 05/07/17) From what I can see from your pictures your wiring is electrically correct.

What brand alternator are you using? Doesn't look like the commonly used Delco. Is it a one wire configuration? Alternator case should ground through the mount, so do alternator instructions call for an extra ground wire?

One possibility for the oil pressure switch is that it was used to turn on a previous Delco 3 wire alternator. One side of pressure switch to switched side of on/off switch, and other side of pressure switch to #1 pin of 2 pin plug on alternator. Makes no difference which way the pressure switch is connected.

With out some form of isolation (switch, indicator light, resistor, or diode) there may be feed back from #1 pin of alternator to output of ignition switch to coil that will cause the engine to continue to run when the ignition switch is turned off.

Your alternator should be negative ground and -- post on coil should go to distributor.

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Thanks for the help I believe its a Delco calls out for a ground wire the only hook up instructions call for a voltage regulator here's a copy of the 2 installs it shows

Thanks Old Ill take a look at the coil and let ya know Yea there's no hour meter on it just never got it to charge now this is a new alternator just like what I took off.
Thanks again Byron

A coil with 3 ohms resistance between + and - posts is a direct 12 volt coil and does not require an external resistor. In fact, it will likely have hard starting and poor running problems if one is added.

A coil with 1 1/2 ohms between + and - can be labeled either 6 volt or "12 volts external resistor required". For 12 volt system it requires an external resistor with resistance approximately equal to resistance of the coil. This is to limit current and prevent burning of points and overheating the coil.

With points open, either coil should read near battery voltage at input side and output to side of the distributor.

With points closed a Direct 12 volt coil (3 ohm) should read near battery voltage at input and near zero volts at coil to side distributor wire.

With points closed, a 1 1/2 ohm coil with resistor in 12 volt system should read near battery at input to the resistor, approximately half battery voltage at input to the coil, and near zero volts between output of coil and side of distributor.

In reality, there is no separate resistor inside of a 3 ohm coil. The coil is a transformer with one side of primary and one side of secondary (high voltage side) tied together. The primary resistance is determined by the type of wire and number of turns used.

Coil in the picture appears to me to be blue with gray over spray. I'd not be surprised if it is a 3 ohm direct 12 volt coil.

I'm sure it's not a Delco alternator. The terminal markings on the regulator appear to me to be Ford, perhaps a Motorcraft alternator.

Hopefully you have the regulator for that alternator? It will not work without it.


You have done a very good job with the pictures. They are a big help.

Yep been 2 years sitting I couldn't remember but I think your right Here's a pic of a motorcraft I pulled up

Thanks for the help Byron

Ill check it out tomorrow let ya know
Thanks Byron

This was bolted to the alternator with one bolt I believe. No idea what it is. It was not hooked up its got 8.53 ohms resistance maybe someone knows
Thanks Byron

Looks like a cut out for a generator. Cut in (connected) when generator output voltage reached a preset level above battery voltage and cut out (disconnected) when generator voltage dropped below battery voltage

The "regulating" was done manually through a resistor on the light switch. Not used with and alternator

(quoted from post at 13:48:02 05/07/17) Looks like a cut out for a generator. Cut in (connected) when generator output voltage reached a preset level above battery voltage and cut out (disconnected) when generator voltage dropped below battery voltage

The "regulating" was done manually through a resistor on the light switch. Not used with and alternator

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OK thanks Ill get rid of that unless someone wants it
Thanks Byron

Ok here's what I got On the coil
Power off negative to positive post 0.00 ohm's 8.38 ohms from each post to coil tower

Points open power on positive and negative post to body ground 12.53v Wire on distributor to body ground 12.53v
positive to negative post on coil 0.00v

Power on points closed 11.2v post to post on coil, Negative post on coil to distributor wire 0.02v
Thanks for any help or insight on this
Note: am I going to need a voltage regulator on this?
Byron

Thanks so I remember now this alternator was for a 1970 ford falcon the new one is identical to the one it had when I bought it
Thanks Byron

Your coil plainly says, 12 volt no external resistor required. It should read 3 ohms across + and - and somewhere in the 6000 to 9000 range from either post to center. 8.38 ohms and 0 ohms tells me you have your meter set on the x1000 scale. The 8.38 would be X 1000 and the 3 ohms is too low to distinguish so it will see it as no resistance. Voltage readings are within expectations.

Put the coil back on and don't worry about it. - post to distributor and + post to on/off switch output

Yes, you definitely need a regulator for the alternator. No you do not need a resistor for the coil.

If it were mine, rather than investing in a regulator I would change it to a Delco internal regulated alternator from early 80's GM vehicle, or a smaller case Hitachi from a late 70's - early 80's Datsun/Nissan. They both wire up the same. Choice might depend on mounting room

(quoted from post at 00:56:27 05/08/17) Your coil plainly says, 12 volt no external resistor required. It should read 3 ohms across + and - and somewhere in the 6000 to 9000 range from either post to center. 8.38 ohms and 0 ohms tells me you have your meter set on the x1000 scale. The 8.38 would be X 1000 and the 3 ohms is too low to distinguish so it will see it as no resistance. Voltage readings are within expectations.

Put the coil back on and don't worry about it. - post to distributor and + post to on/off switch output

Yes, you definitely need a regulator for the alternator. No you do not need a resistor for the coil.


If it were mine, rather than investing in a regulator I would change it to a Delco internal regulated alternator from early 80's GM vehicle, or a smaller case Hitachi from a late 70's - early 80's Datsun/Nissan. They both wire up the same. Choice might depend on mounting room

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OK Got it yep mounting room. Ill see what I can do those old alternators are cheap. Yea I remember many a day having to mess with the points and I cant really remember what else it was on those voltage regulators don't need that hassle that's
been 45 years ago Could you take a look at the pics and see if that's what I need
Thanks for all the help
Byron

That's the common Delco

Get a plug with short pigtails for the 2 pin edge connector

Loop #2 down to output stud, output stud to ammeter

Connect #1 through your oil pressure switch to output (coil) side of ignition switch

Alternator should ground through the mount so get a good clean contact there and you shouldn't need the extra ground wire

Install battery negative to ground

(quoted from post at 05:25:46 05/08/17) That's the common Delco

Get a plug with short pigtails for the 2 pin edge connector

Loop #2 down to output stud, output stud to ammeter

Connect #1 through your oil pressure switch to output (coil) side of ignition switch

Alternator should ground through the mount so get a good clean contact there and you shouldn't need the extra ground wire


Install battery negative to ground

Click to expand...

Ok got it Thanks again for all the help folks
Byron