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Discussion Starter #1
This may be a stupid question but I found the instructions a bit vague on this. I've been running the resistor wire on my 65 to the coil. I have the Pertronix module in the distributor. Engine starts easily and runs very nicely but should I be running the coil on a 12V source?


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This is How I read The Instructions,,,


Q. How to correct a low voltage problem​

A. First, if you have an external ballast resistor, connect the red Ignitor™ wire to the ignition wire
prior to the ballast resistor. Second, if you do not have a ballast resistor you must locate a 12

volt source that is controlled by the ignition switch to connect the red Ignitor™ wire to.
 

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Which PerTronix version do you have?

PerTronix-I = coil resistor YES.
PerTronix II or III = coil resistor NO.

Poison Pinto is right - the module always gets full 12v power. Always.
:tup:
David
 

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Discussion Starter #4
Which PerTronix version do you have?

PerTronix-I = coil resistor YES.
PerTronix II or III = coil resistor NO.

Poison Pinto is right - the module always gets full 12v power. Always.
:tup:
David
I have a Pertronix I with an MSD Blaster 2 coil. It's wired using the original wiring that came with the 65 Galaxie (to the coil).


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Discussion Starter #5
This is How I read The Instructions,,,


Q. How to correct a low voltage problem​

A. First, if you have an external ballast resistor, connect the red Ignitor™ wire to the ignition wire
prior to the ballast resistor. Second, if you do not have a ballast resistor you must locate a 12

volt source that is controlled by the ignition switch to connect the red Ignitor™ wire to.
I am not sure that I have a low voltage problem. The engine does run quite well but I wasn't sure if I should have wired it bypassing the resistor wire. I have the Pertronix I module and an MSD Blaster 2 coil. There is no external ballast resistor.


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RULES!!!!!!

1: Pertronix red wire 12 VOLTS KEYED. (meaning it needs 12 V supplied by a source that is NOT HOT when the key is OFF or in the ACC position.

2: Pertronix coils HAVE INSTRUCTIONS some of them are printed on the coil

All Blaster I coils NEED BALLAST RESISTORS! On a FORD made in the 1960's and 70's the STOCK Coil Feed Wire (red with blue or black stripe) IS A BALLAST RESISTOR WIRE, no extra parts are necessary, hook directly to coil +.

If your Coil requires a full 12V {ALL COILS that I've seen say State Voltage Requirements on the coil it's self} Then you must BYPASS the OEM Ford Coil+ wire. PAIG says that Blaster II and III need 12V I think it's only Blaster III coils..... Blaster II- I "thought" still required Ballast resistors...


I hope that alleviates any confusion.
 

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I am not sure that I have a low voltage problem. The engine does run quite well but I wasn't sure if I should have wired it bypassing the resistor wire. I have the Pertronix I module and an MSD Blaster 2 coil. There is no external ballast resistor.
For a PerTronix-I with Blaster 2 coil, correct connections are:

  • Use original wiring with intact resistor wire (ballast) to coil (+) terminal as-stock.
  • Use new wire with no resistance from ignition switch to PerTronix-I module RED wire.
  • Connect PerTronix-I module BLACK wire to coil (-) terminal.
This will give the module full battery voltage (12v+) for correct function and reduced module heating, and give the coil resisted power through the stock PINK resistance wire (equivalent to a ballast resistor) to prevent coil and module overheating.

David

[EDIT] PS: The new wire to the PerTronix RED wire does not have to be large, as it carries very little power for the module, but must be at full voltage. Use whatever is handy. 18 gauge or heavier is suggested just to avoid handling and use damage to a lighter wire. Most automotive wiring is 18 gauge or heavier just for this reason, even if it carries almost no power.
 

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Discussion Starter #9
Cool! Thanks for clearing that up! Ill work on it and let you all know what happens.

Btw, what can I expect to happen? I've been running the car with the Pertronix wired to the coil and haven't really had any problems. But, I asked the questions because I noticed on other threads that others have wired them differently. Would there be a performance advantage?


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Btw, what can I expect to happen? I've been running the car with the Pertronix wired to the coil and haven't really had any problems. But, I asked the questions because I noticed on other threads that others have wired them differently. Would there be a performance advantage?
No. As you've seen, the Pertronix can function fine on something less than a full 12v. With that said, the original instructions were revised to call for a full 12, because some systems were being installed behind resistors that knocked the voltage down low enough to the point that the module didn't work properly.

FROM THE MSD WEBSITE:
Blaster 2 Coil Hi-Performance - 8202
Improved output coil for electronic ignitions, Blaster Ignition or MSD 5, 6, and 7 Series (ballast resistor required for points)

You no longer have points. So it seems silly to leave it in place. you CAN expect a bit of performance from running full battery voltage to your coil, instead of through the stock resistor wire.
 

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To simplify all that...

I think the *simplest* way to do this (with an Ignitor and a coil capable of handling 12v) would be:

just bypass the resistor wire, and go straight from the ignition switch to coil +.
Then go from coil + to the red wire on the the Ignitor module.

Now your module and coil have switched 12v.
 

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Btw, what can I expect to happen? I've been running the car with the Pertronix wired to the coil and haven't really had any problems. But, I asked the questions because I noticed on other threads that others have wired them differently. Would there be a performance advantage?
You can expect problems of poor spark, missing, hard starting, and outright spark failure to not happen because of low module voltage. ;) Without full battery voltage, the module gets closer to inoperative as the voltage gets lower, and operation becomes worse and erratic. The module also heats-up internally as there is less switching voltage to switch it fully ON, adding a form of it's own internal resistance. This internal resistance with lower voltage is what causes the poor running as the power of the coil spark is also reduced by that internal resistance. The engine still runs - just not as well as it should.

Heat kills the modules, and internal heat is the worst kind. This is where PerTronix failures usually come from. Eventually, with long-term connection corrosion and wiring age, the voltage gets so low that module just quits working. Or only works during starting where the factory 12V bypass works, then quits when you let-off the key. Damn PerTronix! LOL No - damn installer! The poor thing would still be working just fine if it was installed correctly.

The common issues with them is sputtering or missing - often light enough to not notice. As a test, you can simply jump a wire from the battery (+) post to the RED module wire, and in marginal voltage cases, the engine will suddenly run better. I've done this a few times. An example is a guy whose engine would quit when he pulled the battery cable to test the alternator. After replacing the alternator and generator twice, he tried running full voltage to the PerTronix - and it ran perfectly after that, even with the battery cable pulled off. Yep, low module voltage from incorrect wiring.

The most interesting was a car that would hesitate or sputter when you gave it throttle, and the owner just couldn't tune it out with the carb. Ignition was suspected, and jumping full battery voltage to the module RED wire suddenly fixed the acceleration hesitation. We removed the temporary jumper wire and the hesitation and sputtering returned. Weird, eh?
You no longer have points. So it seems silly to leave it in place. you CAN expect a bit of performance from running full battery voltage to your coil, instead of through the stock resistor wire.
This is where some of that confusion comes-in, and why I always ask which version folks have. The different PerTronix modules operate differently. The PerTronix-I operates just like points - without dwell control, where the P-II and P-III feature coil dwell control. What this means is that the P-I will flow coil power even when the engine is not running, and will flow unregulated current when the engine is running.

So, what? So, this means the coil will quickly overheat and the module will also, as they both flow high current. This is exactly why the factory used the pink resistance wire with points and stock coils. Now, you have a Blaster2 coil with less than half the stock resistance (flowing double the current) and both the module and coil will fry that much faster. In-fact, with the lack of dwell control in the P-I and no coil resistor, the coil and module can overheat even when the engine is running.

With built-in dwell control, the P-II and P-III do not have this problem, and is why they are spec'ed to run the coil without a resistor or ballast. They also will not overheat if the key is left ON and the engine is not running. This does not mean the P-I is garbage. It's fine and will work and run the engine very well as a "points replacement" - as long as it is wired-in properly.

Sorry for the long explanation, but there are reasons that are sometimes not obvious as to why certain things are done a certain way. Now you know why the wiring should be done as outlined earlier and in the somewhat confusing PerTronix-I instructions. While some folks have wired a P-I to the resisted coil power feed because they can get away with it, remember - they are just getting away with it. Not all do. And, while some have bypassed the resistance wire to their coils, that is just a testament to the robustness of the P-I module, quality of the coil, and luck.

I can also run most Ford engines 2-quarts low on oil without significant problems - but I don't. Some folks get-away with that for a long time though. ;) HTH

David
 

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I can also run most Ford engines 2-quarts low on oil without significant problems - but I don't. Some folks get-away with that for a long time though. ;) HTH

David
Ford engines are tough! I ran my 7.3 about 8 quarts low once. It's fine... Luckily the injectors stopped firing at that point.
 

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Discussion Starter #14
I think bypassing the pink resistance wire would be the way to go. Where do I find this on a 65 Galaxie? Is it coming straight from the ignition switch or is it in the engine bay together with the engine harness?


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Discussion Starter #15
Btw, thanks to all with your input. I guess I've been getting away with this for almost a year now and it should be time to get it right. And to think I drove the car through the summer months here in Dubai like this and summer is just about upon us again.


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PSIG- this is very good information, thanks for going in-depth.

The different PerTronix modules operate differently. The PerTronix-I operates just like points - without dwell control, where the P-II and P-III feature coil dwell control.
I know you know this, but just to state it for anyone following along- the dwell is controlled by the point gap in a points system.

What this means is that the P-I will flow coil power even when the engine is not running, and will flow unregulated current when the engine is running.

So, what? So, this means the coil will quickly overheat and the module will also, as they both flow high current.
Question: In a points application, there would be a resistor in place, and dwell would be controlled by the points lobe riding on the distributor cam. With a Pertronix (Hall Effect trigger), I'm guessing we're losing that dwell control, as its a simple on/off/on/off signal. So...in theory...a Pertronix I has *less* dwell control than a points setup?


With built-in dwell control, the P-II and P-III do not have this problem, and is why they are spec'ed to run the coil without a resistor or ballast. They also will not overheat if the key is left ON and the engine is not running. This does not mean the P-I is garbage. It's fine and will work and run the engine very well as a "points replacement" - as long as it is wired-in properly.

Again, thanks for breaking this down.
 

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PSIG- this is very good information, thanks for going in-depth. I know you know this, but just to state it for anyone following along- the dwell is controlled by the point gap in a points system.
You raise a good point, and one that I glossed-over that needs clarification. Unfortunately, I often breeze past stuff in my head that is important to understanding the concepts. So, to clarify, coil dwell is the duration of time that the coil has electrical current to it before each spark. Dwell angle in a points system is the number of distributor rotation degrees that the points are closed and conducting power to the coil. Dwell angle is a fixed setting in a rotating distributor.

When you then run the engine you include the factor of time. Therefore, at _____ RPM, a dwell angle setting of _____ degrees will allow _____ milliseconds of power flow to the coil before each spark. This is the coil dwell. As RPM increases, due to the fixed distributor dwell angle setting, the coil dwell becomes shorter and shorter, as there is less time in each distributor shaft rotation to accomplish all 8 sparks. Coil dwell decreases. If dwell decreases to the point the coil is not saturated with energy each time, the sparks weaken.

This is the bane of point ignitions for high RPM use, and why various improvements were made to increase coil dwell as years went by, such as dual points, MSD, and electronic modules with variable dwell control. However, if coil dwell increases beyond the point where the coil is fully saturated with energy, the byproduct is heat. Lots of it. So, we also need to control how much energy the coil sees at low or no RPM to prevent coil overheating. That is the function of the resistor in the coil power circuit.

Because the points do not control the coil dwell time, an engine with ignition ON but not running can flow power to the coil for infinite dwell. This will cook the coil without a resistor in-line to reduce the current flow and control the heat produced.

"Controlled dwell" or "variable dwell" then is a dynamic dwell control that does the opposite of fixed dwell, in that it maintains the coil dwell as RPM increases (as far as that is possible in the time allowed), providing a stronger spark at higher RPM, yet reduces dwell at lower RPM to prevent coil and module overheating. This is why we can now use low-internal resistance coils for HEI, as the low resistance allows even faster coil saturation for high RPM, yet the controlled dwell prevents the runaway coil heating at low or no RPM that would occur with fixed dwell angles and no in-line resistances.
Question: In a points application, there would be a resistor in place, and dwell would be controlled by the points lobe riding on the distributor cam. With a Pertronix (Hall Effect trigger), I'm guessing we're losing that dwell control, as its a simple on/off/on/off signal. So...in theory...a Pertronix I has *less* dwell control than a points setup?
The dwell between a points system and a P-I is equivalent. Both are uncontrolled fixed-angle dwell. The only difference is that the power is switched by a transistor instead of mechanical point contacts. This is why the P-I is considered a "points replacement", as it has no advantage over mechanical points in basic operation (except no "bounce" for extended RPM), but has the advantage of no wearing parts and therefore no maintenance of the module. More advanced modules offer more advantages such as HEI power, rev-limiting, multi-spark, etc. While HEI sparks and multi-spark can help most engines with power and economy, features such as rev-limiters or shift lights are of no advantage unless wanted or needed. Unless tuning for every ounce of power or that last fraction of MPG, the P-I is a capable entry-level ignition module for the masses. Does that help in explaining my views?

David
 

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This is probably one of the better write-ups i've seen...nicely done.

a few comments/questions:

Dwell angle in a points system is the number of distributor rotation degrees that the points are closed and conducting power to the coil. Dwell angle is a fixed setting in a rotating distributor.
The dwell angle in a first-gen Pertronix may be fixed (I assume so, as there is no adjustment)- but the dwell angle on a points distributor is determined by the point gap. My '68 shop manual has a section titled "Dwell Angle Check", and "Dwell Angle Adjustment". (apologies for all the quoting), but: "if the dwell angle was below the specified amount, the breaker point gap is too small." and the converse is true, as well.

So- that's where my earlier question came from (is there less dwell control in a P-1 than in a points system?)

And...does anybody know what the dwell angle on a P-1 is?
(just curious)

Because the points do not control the coil dwell time, an engine with ignition ON but not running can flow power to the coil for infinite dwell. This will cook the coil without a resistor in-line to reduce the current flow and control the heat produced.
If the points are closed, yes- current could flow. Only if they're closed.
but in this situation, does the resistor really matter? meaning: would saturating the coil with 12v for 12 hours be significantly worse than 9v for 12 hours (lets say you left the key on overnight.)


my apologies to everyone who is probably bored out of their minds at this point- sorry. i like ignition systems. its one of the few places you can get more HP out of the motor without cracking it open.
 

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This is probably one of the better write-ups i've seen...nicely done.
Thanks. I suppose I should take the time to think about how to structure explanations rather than just spewing what's in my head like I do here. Perhaps more folks would get a faster and better grasp of it all. But, I appreciate the appreciation. Before the Internet, it took me years to randomly learn the relationships of all this stuff before all the lights came on in my head and everything made sense, and I'm still learning as technology moves forward and I try to catch-up. Because the subject involves so many things besides electricity, even most EEs don't really understand ignition systems if they don't also have a real-world understanding of engines. I hope it saves someone else some time or frustration.
The dwell angle in a first-gen Pertronix may be fixed (I assume so, as there is no adjustment)- but the dwell angle on a points distributor is determined by the point gap. My '68 shop manual has a section titled "Dwell Angle Check", and "Dwell Angle Adjustment". (apologies for all the quoting), but: "if the dwell angle was below the specified amount, the breaker point gap is too small." and the converse is true, as well.

So- that's where my earlier question came from (is there less dwell control in a P-1 than in a points system?)
And...does anybody know what the dwell angle on a P-1 is? (just curious)
Yes, the P-I dwell angle is fixed just like points. It has been years since I randomly noticed the dwell on a Pertronix-I with one of my timing lights, but IIRC it was about 30°. A bit more than typical single-point systems. However, you may test differently, as the dwell is also adjustable - just like points.

PerTronix won't tell you this, because it goes outside of "normal" operation and only invites confusion and problems - so I am saying this only for the purposes of education: Just like moving a set of points closer to the distributor cam will reduce the dwell angle, moving the P-I module closer will do the same, and vice-versa. So, the answer is yes, you can adjust the fixed dwell angle of the P-I. In-fact, that is what everyone does when they install it by using the little gap gauge that comes with it. Although, like points, you really don't want to mess with the recommended setting, as most systems will not benefit from any changes - just like recommended point gap/dwell settings.

Hall sensor and point systems are actually remarkably similar. With points, the distributor cam lobes rotate around and push the point arm out and open the point contacts to fire the coil, and then as the lobe recedes, the points close to ground the coil and flow power through it again to repeat the cycle.

With a Hall sensor, the little magnets in the distributor cam ring create magnetic 'lobes' that rotate past the sensor. As one of the lobes approaches, the sensor "feels" it and switches a power transistor on to ground the coil and flow power through it. As the magnetic lobe passes and recedes, the sensor switches the power transistor off, firing the coil. Just like points, but no moving parts.

The dwell can be a bit higher for the P-I, as the opening and closing of the points is instantaneous and without contact noise or arcing. So if your original "control" question was if you technically have any control over the setting of fixed dwell with a module - the answer is yes.
If the points are closed, yes- current could flow. Only if they're closed.
but in this situation, does the resistor really matter? meaning: would saturating the coil with 12v for 12 hours be significantly worse than 9v for 12 hours (lets say you left the key on overnight.)
Oh, it matters.
Using some actual numbers of a stock 1.5 ohm coil/1.5 ohm resistor, a stock 1.5 ohm coil/no resistor, and a Blaster2 0.7 ohm coil/no resistor:

Holy cow - with a stock coil and no resistance, that coil is making double the heat. Smokin'. A Blaster2 without a resistor is like four high-beam headlights burning in your coil can. :eek: Actually, not the whole coil, but that little primary winding wire. That puppy will glow white hot at that level, and it's life span will be measured in moments - not to mention points welding and modules going poof.
my apologies to everyone who is probably bored out of their minds at this point- sorry. i like ignition systems. its one of the few places you can get more HP out of the motor without cracking it open.
Agreed - it's one of the most important places for performance, and even more important to anything on the street or track than at the drag strip. Unfortunately, it's relatively ignored in many circles, and worse - the available information is polluted by salesmen that don't really understand it or unscrupulous marketers that count on the public's general lack of deeper knowledge. It's good to clear the air from time-to-time. Thanks for the opportunity.
:tup:
David
 
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