I KNOW! CALL PERTRONIX DIRECTLY, BUT.....

[PT81PlymouthPickup]

It's Sunday and they're not open. So, I'd thought I'd bug some of you electrical experts here. ? I know the topic Pertronix or not to Pertronix? has been hashed over time and time again. Well after reading here and elsewhere and talking to some local car guys my consensus (so far) is; it's a good product if installed correctly. I really liked the slant 6 conversion, but was just more work and I did not want to hang another control box on this vehicle. I've taken the Pertronix plunge! I consider myself a fair mechanic, but I have to admit weakness when it comes to the electrical side of things. Anyhow, I converted to 12v system long time ago. I've read the directions that came with my Pertronix Ignitor II #92563LS about a dozen times. The mechanical part of the install is going OK, but I did not like how much stress the wires were under if I routed them through the existing opening (as they suggest)in my IGS series distributor. I'm machining a new hole at a more appropriate position and adding a grommet. My confusion is pertaining to the ballast resistor that I have been using for my points. The instructions recommend removing ballast resistors from the circuit for optimum performance, but offer a alternative installation to retain it. The only difference I can figure is that without it, there will be a few more volts going to the coil? I'm thinking about 3 or 4 volts more? I'm uncertain if that's a good or bad thing. I checked my coil resistance at 1.5 ohms. The instructions say "Ignitor II ignition can be used in conjunction with most ignition coils rated at 0.45 ohms or greater"  Any expert or non-expert opinions?  First photo is the way it's been wired for points and the following are how I'm thinking of doing it for the Pertronix module. I plan on keeping the ballast resistor on the firewall, just in case I have to return to the points.

[PT81PlymouthPickup]

Photos loaded out of order. 3rd photo from top was how it was wired for points.  Sorry!

[maok]

Your looking to achieve a total resistance of about 3ohms, so if your coil is 1.5ohm and your ballast resistor is 1.5ohm, your good to go. The other option is the Pertronix coil which is 3ohm, hence the need to remove  the ballast.

[PT81PlymouthPickup]

19 minutes ago, maok said:

Your looking to achieve a total resistance of about 3ohms, so if your coil is 1.5ohm and your ballast resistor is 1.5ohm, your good to go. The other option is the Pertronix coil which is 3ohm, hence the need to remove  the ballast.

Thanks maok!  Pertronix suggests removing the ballast for "optimum performance". Is this just a marketing ploy to get us to buy their coil? Or is their some performance benefit by using their 3 ohm coil? So, if I were to hook it up with the 1.5 ohm coil I have without the ballast what would happen? Overheat the coil?

[maok]

Stick your tongue on it and find out.....lol

 

Remember the power goes through the Pertronix module first then to the coil and to ground, I'd image its also to protect the module  too.

[Jeff Balazs]

If it was mine I would get the matched coil from Pertronix. I have this set up in my daily driver and couldn't be happier with the way it performs. If you take the time to do all this correctly I think you will find that it is a solid investment.

Jeff

[PT81PlymouthPickup]

3 minutes ago, Jeff Balazs said:

If it was mine I would get the matched coil from Pertronix. I have this set up in my daily driver and couldn't be happier with the way it performs. If you take the time to do all this correctly I think you will find that it is a solid investment.

Jeff

Hi Jeff, The only reason I have been hesitating purchasing the coil from them is it has a different diameter then the bracket on my firewall was designed for. The coil I have is 2.250" in diameter. I believe their coils are 2.5" which won't fit? I'm trying to keep things looking stock. Not always easy.

[Plymouthy Adams]

while this may or may not be something you wish to do....you can gut the original bad coil and leave the outer housing and such in place and jumper the replacement in behind this out of sight out of mind.  It is not a hard thing to do and I admit that I have only done this once to same cosmetic appearance.  

[MackTheFinger]

Seems clear enough, "Ignitor II ignition can be used in conjunction with most ignition coils rated at 0.45 ohms or greater"  

 

I installed Pertronix ignitions on several air-cooled VW's and left the Bosch blue coils in place with no problems.

[Adam H P15 D30]

17 hours ago, maok said:

Your looking to achieve a total resistance of about 3ohms, so if your coil is 1.5ohm and your ballast resistor is 1.5ohm, your good to go. The other option is the Pertronix coil which is 3ohm, hence the need to remove  the ballast.

Are you sure about that?  I have a couple of Pertronix coils around they were all 1.5 ohms.  When I toss the modules, I save the coils.  Running one on my 49 with a slant 6 conversion and no ballast.

 

3 ohms is only needed to protect points in a 12v system.  Why would you lower your coil output so much defeating any gain from electronic ignition?

Edited August 3, 2020 by Adam H P15 D30

[Jeff Balazs]

2 hours ago, PT81PlymouthPickup said:

Hi Jeff, The only reason I have been hesitating purchasing the coil from them is it has a different diameter then the bracket on my firewall was designed for. The coil I have is 2.250" in diameter. I believe their coils are 2.5" which won't fit? I'm trying to keep things looking stock. Not always easy.

I get it and I think what Plymouthy suggests would solve the "look" thing.

 

I am a reliability kind of guy and I make most of my decisions based on what I think is going to give me the most. I don't do car shows or even open the hood for just about anyone. It is just the way I am. I have made several mods like this to my truck and all I can say is that for the most part they have made the driving experience better.

[PT81PlymouthPickup]

3 hours ago, MackTheFinger said:

Seems clear enough, "Ignitor II ignition can be used in conjunction with most ignition coils rated at 0.45 ohms or greater"  

 

I installed Pertronix ignitions on several air-cooled VW's and left the Bosch blue coils in place with no problems.

Yes, I agree. It seems fairly clear, except for the word "most"? What's not clear to me, is why they include the option to install the module with a ballast resistor even though they suggest to install the module without it? I do not want the ballast resistor in the circuit. That's just another thing that can fail. I'm planning on keeping it on the firewall, just in case I ever need to re-install the points (In case of EMP from solar storm or nuclear war) Lols! In my simple mind, without the ballast resistor the only difference would be a few more volts going to the + coil terminal. My coil has worked flawlessly for many years but has been operating on around 9 volts or less with the resistor. I want to be absolutely sure about the right way to install this thing. I don't want to be one of those guys who didn't, and a ruined a $166 module.  I'm going to contact Pertronix and see what they say. I read today Pertronix sells several different coils having different impedance's. Must be a reason?

[maok]

6 hours ago, Adam H P15 D30 said:

Are you sure about that?  I have a couple of Pertronix coils around they were all 1.5 ohms.  When I toss the modules, I save the coils.  Running one on my 49 with a slant 6 conversion and no ballast.

 

3 ohms is only needed to protect points in a 12v system.  Why would you lower your coil output so much defeating any gain from electronic ignition?

 

Were they for a 6 volt system?

[Adam H P15 D30]

No. Both are Flame Thrower coils. One came off a 69 vette, one came off a 67 camaro. 
I am using one of them on my 49. Good coils, bad modules. 

Edited August 4, 2020 by Adam H P15 D30

[maok]

Here is a screen shot from the Pertronix site;

 

If you have the 1.5ohm unit from above table then it would be used with a ballast resistor of 1.5ohm for a 6 cylinder engine.

 

[PT81PlymouthPickup]

23 minutes ago, maok said:

Here is a screen shot from the Pertronix site;

 

If you have the 1.5ohm unit from above table then it would be used with a ballast resistor of 1.5ohm for a 6 cylinder engine.

 

Thanks for posting this maok!  It appears this confirms what you said in earlier post. I will need a 3 ohm coil to eliminate the resistor. They list some options in both chrome and black. I can't seem to find this table at their website and some of the coil #s don't show up there either? Did you just get this from the website? Did I mention I'm a luddite?

[PT81PlymouthPickup]

8 hours ago, Adam H P15 D30 said:

Are you sure about that?  I have a couple of Pertronix coils around they were all 1.5 ohms.  When I toss the modules, I save the coils.  Running one on my 49 with a slant 6 conversion and no ballast.

 

3 ohms is only needed to protect points in a 12v system.  Why would you lower your coil output so much defeating any gain from electronic ignition?

Adam, it sounds like you're not a fan of Pertronix modules? Lols!

[50mech]

I've actually spoken with pertronix techs about this.

The word " most", well it's not likely to work right with some transistorized coils.

In my case I have a pertronix 1 ignition, the module can only handle running I believe a 1.12 ohm coil consistently. Which means a 1.5 with some error margin.  I'm on 6v, if it were 12 it would need to be 3ohms.

Now, I was also told it would actually be no problem running a .75ohm coil with a .75 ballast wired to cutout on cranking. Just as long as I stay up around 1.5 total during running.

 

The issue is current. The pertronix 2 can handle much more current and do so for extended periods while driving. That module can handle the draw of only having a .45ohm coil on 12v so in almost all cases why run a ballast?

Well, only reason  I can think of would be to eliminate ignition crossfire or radio noise. If your wires can't handle op temp plus four or more times the voltage the original system had then maybe you'd want to kick it down a notch while running but keep the easy start.

Edited August 4, 2020 by 50mech

[50mech]

10 hours ago, PT81PlymouthPickup said:

Thanks for posting this maok!  It appears this confirms what you said in earlier post. I will need a 3 ohm coil to eliminate the resistor. They list some options in both chrome and black. I can't seem to find this table at their website and some of the coil #s don't show up there either? Did you just get this from the website? Did I mention I'm a luddite?

If you had an ignitor 1...I thought yours was a 2....which then the chart says .6 or .45

 

With. 1.5 ohm coil you'll be perfectly fine, you'd be well under it's max operating current with no ballast.  You're just not using it to run the hottest coil it can run.

Edited August 4, 2020 by 50mech

[Adam H P15 D30]

1 hour ago, PT81PlymouthPickup said:

Adam, it sounds like you're not a fan of Pertronix modules? Lols!

No I am not. Too fragile

I see no point with having an electronic ignition if you still keep 3 ohms primary resistance.

Edited August 4, 2020 by Adam H P15 D30

[MackTheFinger]

14 hours ago, PT81PlymouthPickup said:

Yes, I agree. It seems fairly clear, except for the word "most"? What's not clear to me, is why they include the option to install the module with a ballast resistor even though they suggest to install the module without it? I do not want the ballast resistor in the circuit. That's just another thing that can fail. I'm planning on keeping it on the firewall, just in case I ever need to re-install the points (In case of EMP from solar storm or nuclear war) Lols! In my simple mind, without the ballast resistor the only difference would be a few more volts going to the + coil terminal. My coil has worked flawlessly for many years but has been operating on around 9 volts or less with the resistor. I want to be absolutely sure about the right way to install this thing. I don't want to be one of those guys who didn't, and a ruined a $166 module.  I'm going to contact Pertronix and see what they say. I read today Pertronix sells several different coils having different impedance's. Must be a reason?

 

Looks like the higher resistance coils are for first generation Ignitors or points ignition. The ones I installed were first generation Ignitors. The German Bosch blue coils are 3 ohm and I don't remember having ballast resistors on them. I'll take a look later today.

 

IIRC those things were $100.00 cheaper when I bought them 30 years ago but a hundred dollar bill was $100 cheaper back then, too/ ?

[Pete]

I've been looking into a Pertronix setup for my 39 Plymouth. I got the coil dimensions from their website and measured the diameter my my current firewall mounted coil. The Pertronix coil is only slightly smaller. Might not even need to shim it to fit the stock bracket.

 

Pete

 

[PT81PlymouthPickup]

10 hours ago, 50mech said:

If you had an ignitor 1...I thought yours was a 2....which then the chart says .6 or .45

 

With. 1.5 ohm coil you'll be perfectly fine, you'd be well under it's max operating current with no ballast.  You're just not using it to run the hottest coil it can run.

Thanks 50mech!  I had too many beers last night and read the chart wrong.  I apologize to everyone for confusing things more than they already are. Yes, I have the Ignitor-II module. So, according to the chart maok posted I should probably have their .45 or .6 ohm coil which gives me a hotter spark? Their .45 ohm coil however is not a round stock looking coil, so it looks like #s 45001 or 45011 flamethrower 2 coils would be the best choice for my truck. Only difference being one is chrome and one is black  Summit Racing lists them having a 2.125" diameter. If that's correct, I should be able to make it fit in my oem coil bracket. Agreed? From what I'm deciphering, my 1.5 ohm coil would probably work OK without the ballast resistor, but spark would be not as hot?  Am I on track here? I'll see if Pertronix confirms this.

[50mech]

Yep, sounds right. Except the hotter spark...a hotter coil doesn't necessarily mean a hotter spark.

 

All those recommendations should be read as, or greater.

The module isn't all that special, it does one thing; break contact when the coil needs to fire. It's a switch, with current limitations. The current runs through it and that's the limiting factor. If reliability is the main concern then a higher resistance is better. Why run the module at it's limits.

 

I see no need to run 60kv coil. As far as I know you aren't running spark quenchingly high 11:1+ compression or anything like that.

 

In fact, you likely won't ever even actually see a 40kv discharge....or even close. The coil is going to fire at whatever the minimum voltage is to ionize the plug gap. That increases with plug gap, rich mixtures, high compression, extreme temperature etc.

 

With 40kv on one of these low compression low rpm beasts you can run your plug gap out to probably .065 and be great and still probably not pushing the coils limits. ( Btw without a plug gap change your spark will not see a voltage increase no matter the coil, just current)

 

So your 1.5 is probably as well suited as anything else as long as it can handle full voltage all day.

So for me, slap in a 1.5 flame thrower coil w no ballast. Set the gap at .045 on plugs. Call it a day. Rest easy knowing I'm not pushing the limits of any component of the system.

Edited August 4, 2020 by 50mech

[Jeff Balazs]

These engines are in a very soft state of tune for the most part. It does not take a super hot spark to keep them happy.

 

The real benefit of using a module like this is fewer moving parts... avoiding sub par points and condensers...and the inside of the distributor cap and rotor stay much cleaner. This is why I converted mine.....and it never fails to start and run right. Day in...day out.

Jeff