Rembrant's new non-Bullnose project

[Gary Lewis]

As for you finding 4.6 ohms on the primary vs the spec of 0.8 - 1.6 ohms, have you checked to see if your DVM shows 0 when you put the leads together? Low resistances are hard to measure and the leads sometimes cause the readings to be off a few ohms.

Gary, yes sir, I always check and it does read zero with the probes touching.

At the end of the day, it's not a big deal and I'll test it with power on it when I have it all wired up, it's just one of those things that annoys me greatly that it isn't indicated on the outside of the coil one way or another.

You could test the current flow to the coil. At 12.8 volts it should pull 2.8 amps if it has a 4.6 ohm primary.

Similarly, a .8 ohm coil and 1.1 ohm resistor should pull 6.7 amps, and if the coil was to the other extreme of 1.6 ohms it should pull 4.7 amps with the 1.1 ohm ballast resistor.

But w/o the ballast the stock coil would pull from 12 to 16 amps, and Ford obviously realized that much current was too much for the DS-II module.

So if your coil pulls 5 - 7 amps on a 12.8 volt battery then you don't need a ballast resistor.

[Rembrant]

I thought you might be.

Oh...while I have you Gary...

Any suggestions on how to get run-only power to my carburetor choke? I know this has been discussed before, but I'm not remembering how to do this.

I am using a little fuel pump controller, so I guess I could use the fuel pump output to trigger a relay for the choke power.

https://www.revolutionelectronics.com/Products/Fuel_Pump.html

The little Holley pump says it needs to be fused with a 3-5 amp fuse, so it obviously doesn't draw much. The pump controller is rated for 7.5amp...or at least it has a 7.5 circuit breaker.

[ArdWrknTrk]

You could test the current flow to the coil. At 12.8 volts it should pull 2.8 amps if it has a 4.6 ohm primary.

Similarly, a .8 ohm coil and 1.1 ohm resistor should pull 6.7 amps, and if the coil was to the other extreme of 1.6 ohms it should pull 4.7 amps with the 1.1 ohm ballast resistor.

But w/o the ballast the stock coil would pull from 12 to 16 amps, and Ford obviously realized that much current was too much for the DS-II module.

So if your coil pulls 5 - 7 amps on a 12.8 volt battery then you don't need a ballast resistor.

Not only too much current for the dinky trigger wire, but so much current it's likely going to cause arcing of the NSS or clutch safety contacts over time.

[ArdWrknTrk]

I thought you might be.

Oh...while I have you Gary...

Any suggestions on how to get run-only power to my carburetor choke? I know this has been discussed before, but I'm not remembering how to do this.

I am using a little fuel pump controller, so I guess I could use the fuel pump output to trigger a relay for the choke power.

https://www.revolutionelectronics.com/Products/Fuel_Pump.html

The little Holley pump says it needs to be fused with a 3-5 amp fuse, so it obviously doesn't draw much. The pump controller is rated for 7.5amp...or at least it has a 7.5 circuit breaker.

You could tap the alternator stator (bk/wh) wire or implement an oil pressure switch to trigger a relay like Bill Vose did.

[Rembrant]

Not only too much current for the dinky trigger wire, but so much current it's likely going to cause arcing of the NSS or clutch safety contacts over time.

Ya, I'm going to buy a new starter relay with both the "S" and "I" terminals to take care of that, and I'll install the ballast resistor and go with it for now. I'll do some tests once I have the 12v supply all hooked up.

I'll assume it needs the resistor for now. Thanks guys.

[Rembrant]

You could tap the alternator stator (bk/wh) wire or implement an oil pressure switch to trigger a relay like Bill Vose did.

I installed a 3G from a 1996 F150, and everything else is from scratch basically, or with Painless wiring harnesses. I think I'll use the fuel pump output to trigger a relay for the choke. The fuel pump controller relay closes for 3 secs on power up, but won't stay closed until it gets a running tach signal.

[Gary Lewis]

You could tap the alternator stator (bk/wh) wire or implement an oil pressure switch to trigger a relay like Bill Vose did.

I installed a 3G from a 1996 F150, and everything else is from scratch basically, or with Painless wiring harnesses. I think I'll use the fuel pump output to trigger a relay for the choke. The fuel pump controller relay closes for 3 secs on power up, but won't stay closed until it gets a running tach signal.

Sounds like you have things lined out.

[ArdWrknTrk]

You could tap the alternator stator (bk/wh) wire or implement an oil pressure switch to trigger a relay like Bill Vose did.

I installed a 3G from a 1996 F150, and everything else is from scratch basically, or with Painless wiring harnesses. I think I'll use the fuel pump output to trigger a relay for the choke. The fuel pump controller relay closes for 3 secs on power up, but won't stay closed until it gets a running tach signal.

Yep, I see that it works almost exactly like EEC fuel pump controls.

Should be fine since a typical 'Bosch' relay is only using milliamps to pull closed.

Edit: just saying how it has been done in other Bullnose trucks.

[Rembrant]

Sounds like you have things lined out.

I do...I think! One more question then...

What would happen if I installed this coil with 4.6 ohm primary into a Bullnose truck with a 1ohm resistor in the coil wiring? (PS: I just check the resistor that came with the Painless wiring kit, and it is reading 0.8 ohms).

I guess what I'm trying to say is, if I install the resistor, and it technically isn't even needed, will there be a negative effect on the ignition?

Can you think of a reason why an aftermarket coil would have such a high primary resistance? Would there be a reason for them to engineer it that way?, assuming the system it's being install in, like a Bullnose, doesn't require it.

[Rembrant]

Yep, I see that it works almost exactly like EEC fuel pump controls.

Should be fine since a typical 'Bosch' relay is only using milliamps to pull closed.

Edit: just saying how it has been done in other Bullnose trucks.

I'm going to do just that Jim, thanks! I bought the controller to protect the pump (and for other safety reasons), but it will serve as a fine trigger for a choke relay. Any idea how many amps or milliamps a typical Holley choke pulls?