ballast resistor/wire or resistor coil?

[TDubya]

My sister's 74 has a Centech harness and dies after getting up to temp. Did the Broncos come stock with a resistor wire and do the aftermarket harnesses have one or do you use a resistor coil with them? I don't have the Bronco here to diagnose the problem right now.

 

[71broncman]

Factory harness had a resistor wire. Centech harness has a ballast resistor that the wires run through. My Flamethrower coil has the resistor built into it so I bypassed the ballast resistor. I left the ballast resistor in place in case there is ever a problem with the coil I can use a regular coil and route the wires back through the resistor. The ballast resistor on my Centech harness is ceramic with a wire coil crossing to each set of wiring connectors.
Mark.

 

[TDubya]

Where is the ballast resistor physically located in the Centech harness? Don't hey normally need to be mounted to a metal surface to dissipate heat? I don't know if it matters but its a points type distributor with a Pertronix Ignitor ignition.

 

[Larry B]

Where is the ballast resistor physically located in the Centech harness? Don't hey normally need to be mounted to a metal surface to dissipate heat? I don't know if it matters but its a points type distributor with a Pertronix Ignitor ignition.

I mounted mine in the center of the fire wall and am using the stock coil. Been several years now and works good so far.

 

[DirtDonk]

It's not located anywhere specific. Like already said, it's a separate module so you mount it wherever you want.
If it's ceramic block is not visible on your sisters rig, it was left out.

Firewall's a good spot. But did you ever have a problem with burning paint Larry? Every time I've mounted one up I've had to use spacers or stand-offs, or mount it to it's own bracket, in order to keep it farther away from the painted surfaces.

Paul

 

[TDubya]

If the ballast resistor was left out, should I use one or use a resistor coil? Which is the better option and which resistor or coil should I use?

 

[TDubya]

Factory harness had a resistor wire. Centech harness has a ballast resistor that the wires run through. My Flamethrower coil has the resistor built into it so I bypassed the ballast resistor. I left the ballast resistor in place in case there is ever a problem with the coil I can use a regular coil and route the wires back through the resistor. The ballast resistor on my Centech harness is ceramic with a wire coil crossing to each set of wiring connectors.
Mark.

How did you route the wiring to bypass the ballast resistor? I think I might try a Flamethrower coil as well. Trying to figure out if I have one faulty part or just the wrong combination of parts.

 

[71broncman]

If the harness is wired per Centech instructions the ballast will have a dark blue(IGN PWR) wire on one terminal and 2 ring terminals with a white wire(COIL +)going into blue plug and to the + connector on the coil. I used a small machine screw and connected all 3 ring terminals to bypass the resistor and get full power to the coil with it's built in resistor. I wrapped the connection with friction tape and tucked it up into the harness right by the ballast resistor just in case I needed it again. On a side note I mounted my ballast resistor on the side of the inner fender closer to the starter solenoid. I figured it would dissipate heat better there, just my preference.
Hope this helps.
Mark.

 

[dave67fd]

If she's using the Pertronix, most likely you don't need a resistor wire (or block).
Measure the resistance of the ignition coil. If it's less than 1.5 ohms, keep the resistor. If 1.5 ohms or greater, remove or bypass. You can keep depending on how it's wired. Read the attached fully.
http://www.pertronix.com/docs/instruction-sheets/1281.pdf

If the rig is dying only after it's hot, It would guess it may have other issues.

 

[TDubya]

If the harness is wired per Centech instructions the ballast will have a dark blue(IGN PWR) wire on one terminal and 2 ring terminals with a white wire(COIL +)going into blue plug and to the + connector on the coil. I used a small machine screw and connected all 3 ring terminals to bypass the resistor and get full power to the coil with it's built in resistor. I wrapped the connection with friction tape and tucked it up into the harness right by the ballast resistor just in case I needed it again. On a side note I mounted my ballast resistor on the side of the inner fender closer to the starter solenoid. I figured it would dissipate heat better there, just my preference.
Hope this helps.
Mark.

Thanks Mark, that does help. I've got a 1.5 ohm coil. Is that what you're using?

 

[TDubya]

If she's using the Pertronix, most likely you don't need a resistor wire (or block).
Measure the resistance of the ignition coil. If it's less than 1.5 ohms, keep the resistor. If 1.5 ohms or greater, remove or bypass. You can keep depending on how it's wired. Read the attached fully.
http://www.pertronix.com/docs/instruction-sheets/1281.pdf

If the rig is dying only after it's hot, It would guess it may have other issues.

It runs fine or a while, then runs bad or not at all after a while. It sure seems like something somewhere is getting warm and mucking up the works.

 

[dave67fd]

Check the simple things first. Remove the air cleaner and watch the operation of the choke on the carb. It should be fully open or close to it when at operating temp..

 

[TDubya]

Check the simple things first. Remove the air cleaner and watch the operation of the choke on the carb. It should be fully open or close to it when at operating temp..

Choke is opening up all the way. I'm pretty sure its an electrical/ignition issue because it was frying the points before she installed the Pertronix Ignitor to try and fix the problem. Whatever issue that was present with the points is still there with the Pertronix. That's why I'm wondering if one or more of the components are getting to much/little voltage or current due to a resistance issue or mismatched parts.

 

[DirtDonk]

If the ballast resistor was left out, should I use one or use a resistor coil? Which is the better option and which resistor or coil should I use?

I would. I prefer the full 12v to a resistor myself (simpler) but either way works. You may not have a choice though as which coil you use may depend on the rest of the ignition anyway.

Do you know if it's got points or Duraspark or something else?
(edit: sorry, I saw you mentioned Pertronix but went out of my head there for a minute.;D ) But do you know what model it is? Could be an Ignitor I, II, or III.
With some you can use certain coils with 12v and others need the resistor still.

You can read about some of them here of course: http://www.wildhorses4x4.com/category/broncoperformanceignition

This one needs a resistor with an Ignitor I, but not necessarily with an Ignitor II: http://www.wildhorses4x4.com/product/Flame_Thrower_II_Coil_Black

This one should be ok with 12v with either Ignitor: http://www.wildhorses4x4.com/product/Flame_Thrower_Coil_Black

If going for the gusto, get an epoxy filled canister coil (as opposed to oil-filled), or E-core coil if the rig is going to be run hard and put away wet, or heat and vibration is much of a concern.
We don't stock that type, but can order them. Hopefully if enough people want them we'll bring them in for regular inventory. I've run them and never worried about overheating a coil, or having a leaker after that.

Paul

 

[TDubya]

I would. I prefer the full 12v to a resistor myself (simpler) but either way works. You may not have a choice though as which coil you use may depend on the rest of the ignition anyway.

Do you know if it's got points or Duraspark or something else?
(edit: sorry, I saw you mentioned Pertronix but went out of my head there for a minute.;D ) But do you know what model it is? Could be an Ignitor I, II, or III.
With some you can use certain coils with 12v and others need the resistor still.

You can read about some of them here of course: http://www.wildhorses4x4.com/category/broncoperformanceignition

This one needs a resistor with an Ignitor I, but not necessarily with an Ignitor II: http://www.wildhorses4x4.com/product/Flame_Thrower_II_Coil_Black

This one should be ok with 12v with either Ignitor: http://www.wildhorses4x4.com/product/Flame_Thrower_Coil_Black

If going for the gusto, get an epoxy filled canister coil (as opposed to oil-filled), or E-core coil if the rig is going to be run hard and put away wet, or heat and vibration is much of a concern.
We don't stock that type, but can order them. Hopefully if enough people want them we'll bring them in for regular inventory. I've run them and never worried about overheating a coil, or having a leaker after that.

Paul

Its the Ignitor I and I've got the Flamethrower I coil ready to install, which Pertronix says to use. The confusion comes from the fact that in one sentence they say compatible for use with the stock resistor wire and in the next they say recommended for use with a full 12v! Still don't know what caused the original problem of the points burning up. I'm hoping that it was just the coil crapping out after it gets warm. Going to try bypassing the ballast resistor (Centech harness) and going 12v to Ignitor and new coil.

 

[DirtDonk]

I should probably clear that up on our page, but I'll double check their information before I do. I thought it was just ok to use with a stock resistor wire when used with the stock Duraspark ignition. But when used with an Ignitor, it could be used with 12v.

That was my take on it anyway. I'll see if I can confirm.

Paul

 

[dave67fd]

The confusion comes from the fact that in one sentence they say compatible for use with the stock resistor wire and in the next they say recommended for use with a full 12v!

.
Not in the info I have.

Eight cylinder engines require a minimum of 1.5 ohms of primary resistance. Do not remove resistors if the coil primary resistance is less than 1.5 ohms.
If your Ignition coil has the recommended primary resistance, remove or bypass all external resistors.

Many vehicles came equipped with ballast resistor or resistance wire. To achieve optimum performance from the Ignitor ignition
system, we recommend the removal of these components.
To remove a ballast resistor, (normally white ceramic blocks 3 to 4 inches long), disconnect all wires on both ends of the ballast
resistor. Remove the resistor from the vehicle and splice the disconnected wires together at a single point.

To remove a resistance wire, trace the coil power wire, which was previously connected to the positive coil terminal, back to the fuse
block. Bypass this wire with a 12-gauge copper stranded wire.

If using the Pertronix I, it may have been damaged by leaving the key "on" when not running. Purchase the II it doesn't have that problem.

Also, read the link I sent you. There is a troubleshooting guide there.
Remember, you will see 12V on both sides of the resistor regardless. If you have the flamethrower now, REMOVE resistor or resistor wire. If you still have the problem (and you read the proper troubleshooting steps) it is most likely damaged or you have other issues

 

[TDubya]

Thanks, that clears it up for me. I'm going to install the new coil and bypass the ballast resistor and hope for the best. I'd better get a card on Brother's Day for this!