351c distributor

[detritusmaximus]

Where did Ford connect for electric chokes?

On the Opel I ran a new nonresistor wire to the coil and connected my choke wire to that. But it was easy to connect to the fuse box where the resistor wire was originally and ran the wire thru the firewall. Easy, but a different type of car.

The relay sounds good. Similar to what we do on the Opel GT to eliminate all the headlight power going thru the dash/fuse box (makes for bad electrical fires...). We run new power off the battery/auxiliary fuse box under the hood with fuses and a relay. The relay is controlled by your original wiring. A few extra items under the hood and no surgery, no changes in the dash.

But, with using the resistor wire, will it activate the 12v relay? 

 

[71fast]

So what is a good solution? The time to address this is before I pull my hair out. Stanglover, more specific on bypassing the resistor?

Where is a good place to tie in the electric choke?

Hi Ryunker,

Pdf diagram will show the 71 stock choke hookup.

Jpg diagram will show the resistor wire you may not have noticed.

I just installed my resistor wire bypass and tach conversion, but didn't use the wire yet until I buy a 12V coil.

happy trails

ken

View attachment 55224

Ryunker.pdf

 

[Don C]

Ford connected the choke to the stator connector on the alternator. This provides power only when the engine is running, so leaving the key on will not cause the choke to open. However, this only provides around 8 volts and aftermarket carburetors require 12 volts. This may slow down the aftermarket choke opening slightly.

The Pertronix relay is designed to operate on the reduced voltage from the resistor wire to the coil, so it would connect there.

If you have an aftermarket carburetor I would add another Pertronix relay for the choke, triggered by the stator and powering the choke with battery voltage, easier than running a wire from the fuse block and through the firewall. Or, if you're not concerned with the choke opening when the key is on, power it from the relay for the Pertronix module. As noted previously, leaving the Pertronix module powered with the engine not running is likely to damage it.

 

[detritusmaximus]

The Opels originally had hot water chokes, nothing electric, so no oem hookup option for us. Smart people replace the oem Solex with an aftermarket Weber 32/36. That can be set up with hot water, electric or manual chokes. Most go electric to get rid of extra plumbing.

 

[Ryunker]

Ford connected the choke to the stator connector on the alternator. This provides power only when the engine is running, so leaving the key on will not cause the choke to open. However, this only provides around 8 volts and aftermarket carburetors require 12 volts. This may slow down the aftermarket choke opening slightly.

The Pertronix relay is designed to operate on the reduced voltage from the resistor wire to the coil, so it would connect there.

If you have an aftermarket carburetor I would add another Pertronix relay for the choke, triggered by the stator and powering the choke with battery voltage, easier than running a wire from the fuse block and through the firewall. Or, if you're not concerned with the choke opening when the key is on, power it from the relay for the Pertronix module. As noted previously, leaving the Pertronix module powered with the engine not running is likely to damage it.

This "pertronix relay" comes with something, or I need to source it seperate?

 

[Stanglover]

This "pertronix relay" comes with something, or I need to source it seperate?

It's a separate purchase as far as I know, that's why I didn't get one!! 

You asked how I disconnected the pink resistor wire. I found the wire in the junction of the steering column harness and fuse block If I remember, been a while. I did not at that time, have those handy tools to unclip the pin connectors, so I used a very small flat blade screwdriver to unclip the pin. Then I just cut the resistor wire and terminated it, opened the crimp to remove the old bits of wire and soldered in the 12 gauge wire. There are not too many places to fish the wire through the firewall, so I think I just pushed it through beside another wire. It's a case of figure it out as you go I'm afraid. As for the choke wire, I'm not sure where the PO hooked it up, but I do know it's on a 12V keyed circuit. It works fine, so not a concern. I did however wrap all the new wire to the coil and choke etc. with loom wrap tape, just to make it look perdy.

Somewhere, I have a diagram of the Pertronix relay, but where I don't know right now. I'm sure it is probably on their website. You may also find it here in a search. 

 

[Don C]

The part number for the Pertronix relay is P2001.

 

[machphil]

From my personal experience, do NOT buy the Ford version of the Ignitor III UNLESS there has been a major design change. A short back story. In 2012, I had my engine rebuilt. The builder installed an Ignitor III. I could never get the timing to be consistent. The car was put on a dyno and with a digital timing light, the timing could be seen drifting. Later, I had a friend put it on a distributor machine. We could easily see the problem. On the Ford version, with the plates, there is/was a crappy plastic "bushing" that the plates revolve around. This bushing was allowing the plates to not only move laterally, but up and down as well. The meant that the "air gap" that is supposed to be .030", was anywhere between about .010" to .050". After contacting Pertronix with this data, the distributor was returned and they replaced it with a Pertronix Ignitor II and a matching coil (VERY important!!). I'm NOT saying it is a bad unit electronically, but a poor mechanical piece of engineering. Now, to be honest, I have NOT looked at them in the last few years, so hopefully, they have re-engineered the plate bushing to a bearing. If this had a similar bearing as the DuraSpark distributor, it would be a good unit.

MY advice, buy a Pertronix Ignitor II along with the matching coil.

EDIT: Why not look at buying a DuraSpark. They can be bought set up and curved to your engine specs, but I forget the name, maybe Performance Distributors. Be aware of Chinese knock offs.

Am I correct in assuming you put this in a single point distributor? The breaker plate anchors are NOT the same between single point and dual point. The best Motorcraft distributor to use is the dual point which rotates on a set of bearings that are concentric with the axis of the distributor shaft. It will provide a much more stable base than the single point which rotates about an anchor point opposite of the vacuum advance arm pin.

 

[Stanglover]

Am I correct in assuming you put this in a single point distributor? The breaker plate anchors are NOT the same between single point and dual point. The best Motorcraft distributor to use is the dual point which rotates on a set of bearings that are concentric with the axis of the distributor shaft. It will provide a much more stable base than the single point which rotates about an anchor point opposite of the vacuum advance arm pin.

That's good to know about the Ford dual point breaker plate. Something I did not know. However, the Pertronix III has it's own plate that replaces the factory one. THAT is where the problem lay. I am not sure, but I believe the Pertronix III for other cars like GM distributors do not have this plate, so those versions MAY fit the dual point plate, just a thought.

 

[mrgmhale]

Ford connected the choke to the stator connector on the alternator. This provides power only when the engine is running, so leaving the key on will not cause the choke to open. However, this only provides around 8 volts and aftermarket carburetors require 12 volts. This may slow down the aftermarket choke opening slightly.

The Pertronix relay is designed to operate on the reduced voltage from the resistor wire to the coil, so it would connect there.

If you have an aftermarket carburetor I would add another Pertronix relay for the choke, triggered by the stator and powering the choke with battery voltage, easier than running a wire from the fuse block and through the firewall. Or, if you're not concerned with the choke opening when the key is on, power it from the relay for the Pertronix module. As noted previously, leaving the Pertronix module powered with the engine not running is likely to damage it.

I absolutely agree with the oem electric choke being connected to the Alternator Stator terminal output, which is less than 12 volts (about 8v AC current [not DC], it only provides power when the engine is running and the alternator is turning & outputting voltage, and aftermarket electric chokes are typically supposed to be connected to 12 volt switched current. If the Stator circuit is connected to aftermarket carburetors requiring 12 volts of current, the choke will be delayed in its opening. With the slow choke opening the spark plugs will likely become fuel fouled and begin to load up. Once the choke is finally open, despite being delayed, the fuel fouled spark plugs should begin to clean up, and the rough running due to an excessively rich Air/Fuel ratio. It is a bit of a nuisance, but at least it becomes corrected once the chock does open.

One way to correct that problem is to connect an aftermarket electric choke to a switched circuit under the engine hook. Beginning in 1972 there is a Red Wire with a Yellow Hash Mark that is an extension of Circuit 640, which was initially used to feed dash illumination lights, and tapped into to feed the carburetor Throttle Position Solenoid (TPS) in some engine configurations. Whether the TPS is present or not, Circuit 640 is part of the main under-hood wiring harness leading to the front of the carburetor. I have a YouTube video that shows where the TPS circuit wiring is located on our 1973 Mustang 302 2v engine. It's link is:


I have attached a schematic snippet file for Circuit 640 to this post as well.

 

[mrgmhale]

This "pertronix relay" comes with something, or I need to source it seperate?

Ryunker, please refer to my comment above. I also provide a YouTube link re: Circuit 640 and the Throttle Position Solenoid Circuit for 72 and 73 Mustangs, which can be used to connect to non oem electric chokes.If you have a 1971 Mustang you may need to connect to an alternate 12 volt switched source. One circuit I have tapped into in the past, when Circuit 640 is not available (1971), is the hot wire at feeding the Windshield Wiper Motor Circuit, where the harness I tap into is on the driver side engine side of the firewall.