Pertronix Ignitor II installation

Heath M

Heath M

Member
I wanted to upgrade my points to pointless using the pertronix ignitor II. For my 1972 Scout II with a 304 and a Holley points distributor (see first image).

I unplugged the battery and removed the cap and rotor. I then removed the points and condenser, removing the wires back through the distributor wall.

Next, I installed the pertronix ignitor II. I started by feeding the wires through the hole in the distributor wall and pushing the rubber seal into place. I ran the wires to the coil (red to positive or "+" and black to negative or "-").

Now... My understanding is that the fabric wire shown in image #2 is no longer used (connected to the green wire at the "+" side of coil). To be safe, I cut the green wire instead. The reason for this is that the fabric wire is an exact length and has to be to use the points. I cut the green ignition wire and added a connector to it and hooked it back to the "+" side of coil.

I added the magnet ring, replaced the cap and rotor (the dust cover no longer fits) and snapped close.

I then reconnected the battery and tried to start. Everything sounded normal, however it never actually fired. I rechecked all connections and tried again. Same thing. I reconnected the fabric wire that I was supposedley not supposed to reconnect and presto!, it worked. It did seem to run a little rough though.

Why does that "circuit 16" resistance wire that is 72" long, to provide a total of 1.8 ohms resistance, needed if the pertronix documentation says it is better left undone... So to speak?

update: took it for a spin and it is most definitely more "robust". That is what popped out of my mouth when the tires lit up, which never happened before.
 

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Are you certain that the first wire you had hooked to the positive side of the coil had 12vdc on it? If there are two wires on the distributor, the "green" wire will probably only be hot when the starter is engaged, the resistance wire is hot with the ignition on.

You will need to run a new wire for the electronic ignition. If you feel the need to keep the resistance wire, find another switched source and power the module through a relay.
 
thehud said:
You will need to run a new wire for the electronic ignition. If you feel the need to keep the resistance wire, find another switched source and power the module through a relay.
Click to expand...

Not sure what this entails? Through a relay?? Can you give an example?

I am quite sure you are correct, I just need a better understanding of how to set this "relay" up.
 
You meant a total of 1.8 ohm, not 18 right? I doubt it's even possible to get 18 ohm of resistance, but if it were, that would undoubtedly be one "hot" commodity and I mean that in the most literal sense possible.
The resistor commonly used to replace the insulated wire is a chrysler application porcelain unit with two male blade terminals which would provide roughly 1.4 to 1.8 ohm of resistance at room temperature when tested across the terminals. That would be combined with a roughly 1.4 to 1.8 ohm primary resistance igntion coil for a total resistance factor of approximately 3.2 ohm, which is the correct amount for a stock inductive ignition system. Now the pertronix module I believe, is meant to be used with a total of 1.8 ohm which would be handled by your coil with a full 12 volt supply and no need of additional resistance. This is why you could dispense with the resistor wire.
Even with improper resistance, the engine should still fire up and run, perhaps not well and not for long before something overheats, but it should run. The reason it didn't run I think is because with the resistor wire unhooked, the coil has no keyed on power supply. You have to feed the coil power somehow. If the pertronix is indeed meant to function with only 1.8 ohm of resistance, then you need to run a new keyed source of power to the coil.
 
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heath m said:
not sure what this entails? Through a relay?? Can you give an example?

I am quite sure you are correct, I just need a better understanding of how to set this "relay" up.
Click to expand...

There are a lot of resources on the web regarding the "bosch" style relays. Essentially your switched wire from the ignition switch (if you are getting at least 10 volts out of the resistance wire you should be able to use it) controls the relay (like a switch) and the 12vdc from the battery will supply the voltage for the coil.
 
No need for no dam relays...this shit is simple! You are simply missing a wire heath!

When ya disconnected the resistor wire (and trev's analysis of that circuit and value is correct), ya lost the "run" feed to the coil positive terminal!!! The other wire that is connected to that terminal is the "start" feed which is a "bypass" that allows b+ to power the primary circuit from the starter solenoid only in the "start" mode. Ya see them two wire run callouts in your schematic for circuit/wire run 16??? Both connect to the positive side of the coil...one is "start", one is "run".

Once it starts, and ya release the key, the ignition switch swaps over internally to the "run" feed which is the resistance wire. That resistance wire can be eliminated if it ever burns out (and it will) and then a simple 1.6>1.8ohm ballast resistor as trev described installed in it's place, with a new feed run from the bulkhead connector which is not a resistive element.

A pertronix conversion (either type) will work just fine off the ballasted (reduced voltage) feed in the run side. But for best performance, witha stock-type coil with a primary resistance of 1.6>1.8 ohms also, it should have a b+ feed wired in.

Most sii harnesses have an extra switched "hot" wire run or two inside that harness that runs down the top of the intake manifold where ya found that resistor wire all scruud up! Those were used on some later rigs for "heated" divorced choke operation, and/or an "anti-diesel" solenoid on a carburetor (you don't have that item on yours), etc. Open up that harness and have a looksee, if those deadheads are there, pick one, verify that it's a "hot" run when the key switch is in the run position, and use that for yore b+ feed to the coil.

The trigger signal to the ignition primary circuit using the pertronix is far more accurate and consistent than any breaker point trigger can ever hope to be!!! That is why those units provide exceptional performance as compared to a point set. But...ya still need to do that "power timing" deal again, the timing changed when ya installed the p-tron! Check this thread:

http://www.forums.IHPartsAmerica.co...es-pertronix-require-timing-readjustment.html
 
michael mayben said:
A pertronix conversion (either type) will work just fine off the ballasted (reduced voltage) feed in the run side. But for best performance, witha stock-type coil with a primary resistance of 1.6>1.8 ohms also, it should have a b+ feed wired in.
Click to expand...

So, I am going to dig in the harness for a hot "run" wire (or wire one up) that will go straight to the positive side of my p-tron 0.6 ohms coil and do away with the circuit 16 resistor wire altogether. Should work fine... I think.
 
michael mayben said:
no need for no dam relays...this shit is simple! You are simply missing a wire heath!
Click to expand...

Last time I checked, relays were not that difficult. And since heath expressed the desire to keep the resistance wire the easy way to accomplish this is use the resistance wire as the switch for a powered relay. There isn't anything difficult about it.

On the plus side you get a more reliable voltage source to the coil and are eliminating the amperage demand from the ignition system from the ignition switch and the dash harness.

To each their own, but I just don't like putting anymore of a load on the old wiring than I have to if I can.
 
thehud said:
last time I checked, relays were not that difficult. And since heath expressed the desire to keep the resistance wire the easy way to accomplish this is use the resistance wire as the switch for a powered relay. There isn't anything difficult about it.

On the plus side you get a more reliable voltage source to the coil and are eliminating the amperage demand from the ignition system from the ignition switch and the dash harness.

To each their own, but I just don't like putting anymore of a load on the old wiring than I have to if I can.
Click to expand...

Hud, reviewing what heath wrote I don't see where he ever expressed any desire to actually keep the resistance wire. I think he just wants his new p-tron setup to work properly. That oem insulated wire is an electrical fire waiting to happen after all these years. It's been explained in detail that he can either run a ballasted feed via a block resistor or straight b+ voltage to his coil, but either way he would be well served to eradicate that oem resistor wire. I think we can all agree, there is nothing that complex about either choice.
 
scoutboy74 said:
hud, reviewing what heath wrote I don't see where he ever expressed any desire to actually keep the resistance wire.
Click to expand...

For some reason when I read it last night it seemed like for some reason he wanted to keep it in place so he could change back to points in a pinch.

If the bhc on his 72 takes standard packard series 56 terminals, then the easiest thing would be to remove the wire from the bhc and then replace it with a new 16 gauge wire. (assuming that he wants to remove the resistance wire).

Maybe I was just tired when I read it.
 
thehud said:
last time I checked, relays were not that difficult. And since heath expressed the desire to keep the resistance wire the easy way to accomplish this is use the resistance wire as the switch for a powered relay. There isn't anything difficult about it.

On the plus side you get a more reliable voltage source to the coil and are eliminating the amperage demand from the ignition system from the ignition switch and the dash harness.

To each their own, but I just don't like putting anymore of a load on the old wiring than I have to if I can.
Click to expand...

There is no reason to eliminate the resistor wire...but in heath's case (and this is only because I've worked with his rig) it is a dangerous item!

I never do anything to the harnesses that would prevent going back to a point set in the event the p-tron or any other upgrade should fail unexpectedly. Ya simply deadhead the resistance wire and leave it in the harness if it's good and not burned internally in the harness and has become a fire hazard which is very common on all ihc vehicles, not just a Scout II with points.

If there is concern about "old wiring", then that is why we upgrade and repair stuff, we don't just "reduce the load".

If the harness already has other switched b+ wire runs, then just use one of those, can't be any simpler! You will not see those callouts in the schematics, you must open the individual harness loom and look to see what your rig has!

The ballasted feed (resistance wire) to the coil positive terminal was also used on millions of GM vehicles in exactly the same manner, there is nothing wrong with that system. The problem is the bulkhead connectors that IH used in oem apps and the fact they buried the wire in a totally bogus manner in the loom where it's sure to overheat and make a mess. On many IH vehicles, the resistance wire run is buried in the same manner inside the cab, under the dash in the loom. And primary current with an oem IH point ignition system is well under four amps at 2500 rpm.

The greatest "problem" regarding the installation of the pertronix conversion is the lack of definitive instructional material for specific installations. And if you had been selling this stuff at retail back in the 70's and 80's as the original "perlux" conversion, you would have been inundated with irate customers who couldn't figger this shit out. That was a major reason in why we made a decision back then to no longer sell the stuff over the counter unless we installed it also. And their instructions today are not much more complete as they do not explain the "why" and provide specific instructions for each vehicle/distributor system variation. Some of their instructions are just plain wrong, such as the enclosure/diagram for the p-tron conversion for a Holley gold box distributor!
 
heath m said:
so, I am going to dig in the harness for a hot "run" wire (or wire one up) that will go straight to the positive side of my p-tron 0.6 ohms coil and do away with the circuit 16 resistor wire altogether. Should work fine... I think.
Click to expand...

From this statement..I gather you also installed a replacement pertronix coil also? Since you stated 0.6ohms, that would have to be the "flamethrower II" coil series. That coil can only be used with the pertronix II conversion or a add-on cd ignition box such as a mallory/msd/crane/accel "6 series" unit.

Ya can't use that coil with the oem points distributor setup, even with the ballast wire or a replacement (repair item) ballast resistor. A v8 points (inductive) ignition needs a coil with a primary resistance of 1.6>1.9 ohms for proper coil "saturation" and control of primary current, otherwise breaker point life will be greatly reduced (under 30 minutes runtime??). Best primary current for the inductive ignition systems is in the range of 2.5 amps or so at say 2200rpm with a hot ignition system.

And trever has received the "primary resistance" lecture in an intense session at binder u. At the bee last year when sailor jerry was not included in our training!!!! Sailor jerry is on scholastic probation and can only join us during hazing operations conducted for incoming freshpersons.

Now that I have the analyzer running again (and also another unit that lyle left here last Saturday), we can run your fresh ignition system and you will see the drastic improvement in overall ignition performance in a graphical environment. And with your photo skills, I bet we can get some nice shots of the scope screen that we can post here for illustration!

This is way cool that you have gone from a frozen distributor inna rig that is near terminal, to a fresh p-tron powered, state of the art system in warpspeed! And ya did it yoreself!
 
michael mayben said:
if there is concern about "old wiring", then that is why we upgrade and repair stuff, we don't just "reduce the load".

The ballasted feed (resistance wire) to the coil positive terminal was also used on millions of GM vehicles in exactly the same manner, there is nothing wrong with that system. The problem is the bulkhead connectors that IH used in oem apps and the fact they buried the wire in a totally bogus manner in the loom where it's sure to overheat and make a mess. On many IH vehicles, the resistance wire run is buried in the same manner inside the cab, under the dash in the loom. And primary current with an oem IH point ignition system is well under four amps at 2500 rpm.

The greatest "problem" regarding the installation of the pertronix conversion is the lack of definitive instructional material for specific installations. And if you had been selling this stuff at retail back in the 70's and 80's as the original "perlux" conversion, you would have been inundated with irate customers who couldn't figger this shit out. That was a major reason in why we made a decision back then to no longer sell the stuff over the counter unless we installed it also. And their instructions today are not much more complete as they do not explain the "why" and provide specific instructions for each vehicle/distributor system variation. Some of their instructions are just plain wrong, such as the enclosure/diagram for the p-tron conversion for a Holley gold box distributor!
Click to expand...


By "reducing the load", I mean removing higher current draw circuits from the long and winding road back through the dash and out under the hood again. In my opinion one of the first things that should be done to any piece of equipment is to remove the amp gauge and leave the main power under the hood at a terminal distribution block. That will drastically reduce the voltage drop in the system.

IH made some interesting decisions with their wiring. I never did understand why they put fusible link wire in the dash. Why put something that fails by burning out in an area with carpet? And their wiring woes were not restricted to light trucks. Agricultural equipment had worse wiring in my opinion.

Unfortunately a lot of after market upgrades do not come with very complete instructions. The pertronix kit leaves a lot to the person doing the install to figure out on their own. It isn't too bad for those that have a reasonable amount of experience, but for a casual hobbyist it can be a lot to wrap your mind around.
 
I appreciate everyones input (it really helps the next sucker). Let's keep it peaceful on this thread.

I have already had one wire fry in the bulkhead connector. It is a shoddy setup prone to failure (at least in 1972). Also, knowing it is just a matter of time before that resistor wire, or better known as "toaster heating element", fries all the wires in that harness doesn't help me sleep any better either. That resistor wire has to be exactly 72 inches long, which means it is double coiled in spots within the harness. This promotes more heat in the harness. Less heat... Good, more heat... Bad.

As I said before, I will be eliminating that toaster wire and using another source for my power to the coil. Eventually I will be upgrading the entire wiring system, but till then, it is an available wire or a mcguyver wire, whatever works safely.
 
heath m said:
as I said before, I will be eliminating that toaster wire and using another source for my power to the coil. Eventually I will be upgrading the entire wiring system, but till then, it is an available wire or a mcguyver wire, whatever works safely.
Click to expand...

Then by far the easiest ways are to either:

find a secondary switched source.

Or remove the resistance wire from the bhc and replace it with a fresh wire.

Does your bhc had flat terminals or round ones? I'm more familiar with the later harnesses that had the 56 series connectors. If it has the flat packard connectors you can pick a few of them up at napa. If they are different (and without seeing one I couldn't even begin to identify it), then you May have to be careful and remove the wire from the connector and then crimp and solder the new wire to the old connector in the bhc (not the best way, but not awful either). And while you are at it it would be a great time to clean the daylights out of the bhc anyway.

And no worries, this is just some healthy discussion.
 
So, I'm supposed to not have the resister hooked up and run direct power? Because I do have the resisted hooked up.

I've got the petronics and the flame thrower coil.
 
At some point, the resistor wire is going to go. When it does it will probably melt every wire it touches.

I am currently using the resistor wire, however, I always have it in my mind that I need to replace it with a safer alternative before anything happens.

Hope that helps.
 
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