Ignition Coils

[Christopher R.]

For my 1962 with a points type ignition, I'm going to run a Pertronix ignition coil with 1.5 ohm primary resistance and save the "091" coil. For their "091" coil, Chevy specified a ballast resistor. In fact, based on experience in the field with points life, they upped the spec for the resistor from 0.3 to 1.8 ohms.

However, Pertronix specifies no ballast resistor for their coil.

What can I expect for points life?

[Stuart F.]

Re: Ignition Coils

Which Pertronix coil are you using?

Their standard "Flame-Thrower" coil used with the 1.5 ohm resistance (40,000 volt) specifies that if your present ignition system requires a ballast resistor, do not remove it.

Only their Ignitor II system with the 45,000 volt "Flame-Thrower II" coil uses a full 12 Volt input w/o ballast resistor.

Remember, in your situation using points, you are lowering the input voltage with the resistor to SAVE (extend the life of) the points. You do not want to run the points on 12 volts full time with any coil.

Stu Fox

[Christopher R.]

Re: Ignition Coils

Pertronix doesn't want you using a ballast resistor with their electronic ignition systems - the Ignitors.

But I'm going to use their Flame-Thrower coil with a points type ignition system. I'm going to use their standard 40,000 volt, 1.5 ohm coil. #40011. And I've got the instructions in my hand. It says no ballast resistor for a V8. No ballast resistor for high performance 4 and 6 cylinders. Use the ballast resistor for regular 4 and 6 cylinder engines. I'm confused over why the coil would care about how many cylinders the engine has.

[Stuart F.]

Re: Ignition Coils

Christopher;

I don't know what instructions you are looking at, which is not to say they didn't change them since I last used their 40,000 volt coil, but the sheet I have specifically states that "if your system has a ballast resistor, do NOT remove it". Again, remember the concern is for your points - not the coil. It's the points that can not tolerate the 12 volts input. That is why your ignition system is set up to only provide 12 volts (by-pass the resistor)when your ignition switch is in the START position. When it returns to the ON position, the current passes through the ballast resistor to limit the voltage input to keep the points from burning.

Stu Fox

[Jim L.]

Re: Ignition Coils

Again, remember the concern is for your points - not the coil. It's the points that can not tolerate the 12 volts input. That is why your ignition system is set up to only provide 12 volts (by-pass the resistor)when your ignition switch is in the START position. When it returns to the ON position, the current passes through the ballast resistor to limit the voltage input to keep the points from burning.

Not to pick nits, but this explanation misses the mark slightly.

Yes, the health of the points is an issue with the presence or absence of the ballast resistor. But it's not the Voltage that's the problem. In fact, at the instant just before points closure, there is 12 Volts across the points, whether the ballast resistor is present or not.

What the ballast resistor does is limit the current that flows in the primary winding and thru the points. Current limiting is the reason for the ballast resistor, not Voltage limiting.

Jim

[Gary C.]

Re: Ignition Coils

Christopher, why don't you just change to a full Petronix setup and do away with the points. Then you wouldn't have to worry about it. You can always change back to a points system if need to. Have had the Petronix inmy '64 for almost ten years without a hitch. Gary....

[Joe C.]

Re: Ignition Coils

For my 1962 with a points type ignition, I'm going to run a Pertronix ignition coil with 1.5 ohm primary resistance and save the "091" coil. For their "091" coil, Chevy specified a ballast resistor. In fact, based on experience in the field with points life, they upped the spec for the resistor from 0.3 to 1.8 ohms.

However, Pertronix specifies no ballast resistor for their coil.

What can I expect for points life?

Just what are you trying to accomplish?

Pardon me for being so blunt, but I believe that you are wasting your money.

Any coil with internal resistance of (about) 1.8 ohms or less (including YOUR MODEL "Ignitor"), should be run with external ballast resistor, or resistor wire as found on Corvettes after (1968?) or thereabouts.

All coils which have internal resistance of 3 ohms (as SOME "Ignitor" models have) are meant to be run WITHOUT an external resistor. This includes almost all "blaster", "ignitor", "atomic", "cataclysmic", "apocalyptic", and yes, even "hellfire" coils.

Coils which have high internal resistance, and therefore must not be run with external resistor, do not afford the luxury of two parallel feeds to the coil: one with low resistance during cranking, for extry starting current, and one with increased resistance during running, to drop current and preserve the points.

The best all-around ignition system on the market today, is the one which employs a "Hall Effect" transducer, thereby eliminating the points and condenser (capacitor). This system is designed to be used with your very expensive 091 coil (or less expensive alternative), along with external ballast. The system is good to 10,000 RPM (provided the distributor has proper bushing clearances, end play, and is free of breaker plate wobble), and will deliver CONSTANT VOLTAGE of appx 12KV from idle all the way to 10,000 RPM. Air fuel mixtures ranging within acceptable limits need around 5-6KV to ignite..............anything beyond that is "gravy", which is required to overcome any shortcomings in your engine's secondary ignition circuit! If your coil needs to develop more than about 10 KV in order to ignite your engine's A/F mixture, then you have serious shortcomings in your secondary circuit. Running under these conditions for extended periods will stress your coil, cause it to overheat, and fail prematurely.

Joe

[Stuart F.]

Re: Ignition Coils

Thanks for jumping in to explain this better for Christopher. I was trying to keep it simple in dealing with what equipment he apparently already had. I agree with going the Full Pertronix Electronic Ignition route (Pertronix II) as that is what I have used for many years. It is easy to change over for judging too as I have mine set up with ballast resistor in place, but I jumper around it with a hidden wire to provide the full 12 volt source. I started with the basic Pertronix, then upgraded to the II.

I had a Hall Effect unit from Prestolite for a number of years before that, and it worked well but required the Epoxy Encapcilated box on the out side which could not be hidden. It used a multipin connector that had small pins made of rolled brass. They would break internally at the wire crimp and shut you off. It would start right up again when you hit it with 12 volts, then cut off further down the road. Also, the pick up on the distributor used wires that became stiff and brittle over time which would cause the VAC plate to hang up. The wires had to exit the distributor through a special window in the cap with a cut-out in it. I solved that with silicon jacketed wires soldered to the pickup which I could also route through the standard hole in the housing bottom.

SAtu Fox

[Joe C.]

Re: Ignition Coils

Thanks for jumping in to explain this better for Christopher. I was trying to keep it simple in dealing with what equipment he apparently already had. I agree with going the Full Pertronix Electronic Ignition route (Pertronix II) as that is what I have used for many years. It is easy to change over for judging too as I have mine set up with ballast resistor in place, but I jumper around it with a hidden wire to provide the full 12 volt source. I started with the basic Pertronix, then upgraded to the II.

I had a Hall Effect unit from Prestolite for a number of years before that, and it worked well but required the Epoxy Encapcilated box on the out side which could not be hidden. It used a multipin connector that had small pins made of rolled brass. They would break internally at the wire crimp and shut you off. It would start right up again when you hit it with 12 volts, then cut off further down the road. Also, the pick up on the distributor used wires that became stiff and brittle over time which would cause the VAC plate to hang up. The wires had to exit the distributor through a special window in the cap with a cut-out in it. I solved that with silicon jacketed wires soldered to the pickup which I could also route through the standard hole in the housing bottom.

SAtu Fox

Hi SAtu:

Are you related to Sabu?
I much prefer the "other" sytem, which is very simple to install, and uses all of the stock ignition components on the primary side........except the points/condenser. It is cheaper and simpler than the Ignitor II.
It's more expensive than the Pertronix Ignitor I, but not Ignitor II, is undetectable for judging, employs the ballast and standard coil (or service replacement).
It seems to be virtually bulletproof, as there apparently extremely few "horror stories" describing failures. It is what we like to call, an "elegantly simple" design. In the extreme case that a failure occurs, all you need is a small screwdriver, a spare set of points/condenser, and about 10 minutes, and you're back on your way.

[Stuart F.]

Re: Ignition Coils

Joe;

Pardon my typo on my name. At least I didn't mess yours up, Ha! Actually, that is the way they pronounce my name in my wife's country of Thailand; "SaTu".

There sure are some nice products out there now. The "Hall Effect" system I described was good, but had its faults as I noted. It introduced me to the advantages of Electronic Ignition Conversions for which I have been very pleased over the years. I recall having to change my plugs and points so often - it was a chore. As I started my more recent experience with the Ignitor I, I got a deal at the Winter Meet one year for a II and actually made the upgrade w/o removing the distributor as I had already shimmed it for the Ignitor I. It is a pleasure to be able to do a slow show cruise, then bale from there to the highway with assurance that when I hit that ON ramp I'll have my "redline" available to make my merge.

Have a great weekend.

Stu Fox

[Christopher R.]

Re: Ignition Coils

Just what are you trying to accomplish?

Any coil with internal resistance of (about) 1.8 ohms or less (including YOUR MODEL "Ignitor"), should be run with external ballast resistor, or resistor wire as found on Corvettes after (1968?) or thereabouts.

I'm trying to understand why Pertronix is telling me not to use a ballast resistor with their 40,000 volt 1.5 ohm coil. (Sorry, Stuart. I've got the instructions in my hand, and that's what it says.) Of course, the best solution would be to ask Pertronix, which is exactly what I did. But being the weekend, they haven't answered yet. I asking the question here too becuase my experience with tech help is that they'll tell me what to do, but won't tell me why.

I've always believed that any 1.5 ohm coil needed a ballast resistor. But I don't know why I've always thought that. Trying not to be that typical old geezer who can't change his mind. Maybe I missed something. Maybe Ohm's Law changed when I wasn't looking.

BTW, my ultimate goal is to acquire or build this Winter 2 carburetors, 2 coils, 2 distributors, and 2 ballast resistors that I can use next Spring to troubleshoot a newly installed rough running engine. I'd been running the Ignitor 1 on the old engine for 10 years. After I get the engine sorted out, there's a good chance I'll continue to use it. But in the meantime, I want to put together an ignition system in which I have confidence. So seeing that I wanted 2 distributors and coils, I thought I'd build one for judging, and one for the street.

[Joe C.]

Re: Ignition Coils

I'm trying to understand why Pertronix is telling me not to use a ballast resistor with their 40,000 volt 1.5 ohm coil. (Sorry, Stuart. I've got the instructions in my hand, and that's what it says.) Of course, the best solution would be to ask Pertronix, which is exactly what I did. But being the weekend, they haven't answered yet. I asking the question here too becuase my experience with tech help is that they'll tell me what to do, but won't tell me why.

I've always believed that any 1.5 ohm coil needed a ballast resistor. But I don't know why I've always thought that. Trying not to be that typical old geezer who can't change his mind. Maybe I missed something. Maybe Ohm's Law changed when I wasn't looking.

BTW, my ultimate goal is to acquire or build this Winter 2 carburetors, 2 coils, 2 distributors, and 2 ballast resistors that I can use next Spring to troubleshoot a newly installed rough running engine. I'd been running the Ignitor 1 on the old engine for 10 years. After I get the engine sorted out, there's a good chance I'll continue to use it. But in the meantime, I want to put together an ignition system in which I have confidence. So seeing that I wanted 2 distributors and coils, I thought I'd build one for judging, and one for the street.

Christopher,

Sorry for my arrogance. You sound a lot like I did, before I did my homework and educated myself in ignition systems.
The answer to your question is in my first reply to you, above. The "short" answer is "yes, you absolutely should install a ballast resistor in your feed to the coil from the ignition switch". Although it is not NECESSARY that you install one, it is extremely helpful if you do, because your coil has low internal resistance. Again, if you were using any coil with high resistance (most of which are about 3 ohms) then the addition of the ballast resistor would restrict the current flow to the coil to the extent that the engine MIGHT run, the points would last extremely long, but the coil would put out low voltage. Again, so long as that coil voltage is about 6 KV, PLUS enough extra required to overcome any deficiencies in the secondary system (rotor/cap/plug wires/coil wire), then the engine will start and run.
Your Pertronix I system lacks the so called "adaptive dwell" employed by the Breakerless SE or the Ignitor II systems. Because of this, your coil's output voltage drops as your engines RPM is increased, so, if the coil happens to cause the engine to start under these conditions, it would begin to misfire severely, or even "cut out" as RPM's increase.
An excellent "primer" on ignition system "common sense", which is well grounded in theory, can be found here. I suggest that you read it, and digest it:

http://www.lectriclimited.com/breakerless_se.htm

This is not an endorsement of any particular product, although I employ this system on my Corvette. This website does give a very simple explanation which may clear up some of your questions.

Joe

Two more things:

1. The Pertronix website has an application chart, showing that all of the installations where the customer is using their (Pertronix) standard coil, with 1.5 ohm resistance, that a ballast is used.
2. My recommendation to you is, to save your very expensive 091 coil for judging, return the Pertronix "Blaster, Atomic, Cataclysmic, Hellfire" coil, and buy a high quality replacement for your 091, employing 1.5 plus/minus .3 ohms internal resistance.

[Gene M.]

Re: Ignition Coils

The Pertronix 1 says to use a coil of at least 1.5 ohms. I checked a couple replacement coils I have. Readings I get are 0.8, 1.3, and 1.4 ohms on the meter checking them as the instructions say on the two threaded posts. Is this typical readings? Do you think the 1.4 ohm is close enough? On a 72 vette original coil I get 1.5 ohms bouncing back to 1.4 ohms. Will this one be ok with the Pertronix 1? My next step in to check some "202" coils I have.

[Joe C.]

Re: Ignition Coils

The Pertronix 1 says to use a coil of at least 1.5 ohms. I checked a couple replacement coils I have. Readings I get are 0.8, 1.3, and 1.4 ohms on the meter checking them as the instructions say on the two threaded posts. Is this typical readings? Do you think the 1.4 ohm is close enough? On a 72 vette original coil I get 1.5 ohms bouncing back to 1.4 ohms. Will this one be ok with the Pertronix 1? My next step in to check some "202" coils I have.

Gene,

Coil resistance is also temperature dependent. Can vary within about .3-.5 ohms.
I think that some of the more expensive coils, using a special "potting" substance rather than PCB laden oil, are less affected by temperature, as well as vibration.

[Christopher R.]

Re: Ignition Coils

Thanks, Joe. I'm considering the Breakerless SE. But I want to get the engine running right first before I go changing stuff. I've got a known good (tested on a Sun machine) points type distributor. I want to use that first with various coils and ballast resistors.

I've also got an old distributor with one of the original Pertronix Ignitor 1 modules. It has run great for the last 10 years or so. I'm also going to use that one to troubleshoot. But just at the end of last year, when the engine ran rough, but I didn't have time to fiddle with it before I had to put it to bed, I swapped out another (third) coil, and voila, it seemed that the engine ran better. But I can't be sure.

So to eliminate all this guessing, I'm going out into the driveway next Spring armed with 2 carburetors, 3 coils, 2 distributors, and 2 ballast resistors. One of each will have been tested by somebody else on their car or machine, and the other one will be one in which I have 98% confidence.

(All that Six Sigma Green Belt training wasn't wasted on me, by golly.)