Question about Pertronix Ignitor
Thread Starter
Melting Slicks
Joined: Feb 2003
Posts: 2,529
Likes: 27
From: Auburndale Florida
2025 C2 of the Year ('64-'66) Finalist - Unmodified
St. Jude Donor '03-'05-'06-'07-'09
Question about Pertronix Ignitor
Working on a friends 71 350 coupe, chasing some poor running and idling issues. Had to re-shim the distributor and replace the vacuum advance can. Distributor has a pertronix, looked on line for instal instructions. No mention about the gap between the ring and module.
Is there a spec or measurement? Thanks,
Is there a spec or measurement? Thanks,
Le Mans Master
Joined: May 2003
Posts: 8,876
Likes: 3,556
From: Fernandina Beach FL
2023 Restomod of the Year finalist
2020 C3 of the Year Winner - Modified
I don't think it's the Petronix is causing the poor running. The Petronix either works or not- Spark or no spark. I think it's just not at the right time...
Probably need to make sure your timing is correct-Take a look at this- Barry has done a great job-
http://forums.corvetteforum.com/c3-t...long-post.html
Lars has a great paper as well- I think Barry has it linked either on his website or it might be in the thread.
Richard
Probably need to make sure your timing is correct-Take a look at this- Barry has done a great job-
http://forums.corvetteforum.com/c3-t...long-post.html
Lars has a great paper as well- I think Barry has it linked either on his website or it might be in the thread.
Richard
Thread Starter
Melting Slicks
Joined: Feb 2003
Posts: 2,529
Likes: 27
From: Auburndale Florida
2025 C2 of the Year ('64-'66) Finalist - Unmodified
St. Jude Donor '03-'05-'06-'07-'09
I don't think it's the Petronix is causing the poor running. The Petronix either works or not- Spark or no spark. I think it's just not at the right time...
Probably need to make sure your timing is correct-Take a look at this- Barry has done a great job-
http://forums.corvetteforum.com/c3-t...long-post.html
Lars has a great paper as well- I think Barry has it linked either on his website or it might be in the thread.
Richard
Probably need to make sure your timing is correct-Take a look at this- Barry has done a great job-
http://forums.corvetteforum.com/c3-t...long-post.html
Lars has a great paper as well- I think Barry has it linked either on his website or it might be in the thread.
Richard
Car won't idle and acts like it has dropped a cylinder, owner has replaced carb 3 times. May replace wires and plugs after compression ck.
Rebuilt moter has about 500 miles, rebuilt years ago, just sitting around, years, waiting on the frame off restoratio to be completed, thanks
Le Mans Master
Joined: Aug 2006
Posts: 7,423
Likes: 1,558
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Pertronix Ignitor.
As mentioned the PI is most likely not the problem, I have it on my 74, the instructions call for not less than .010 and not more than .060 gap. If you want the full instruction sheet PM me your email address. PG.
Thread Starter
Melting Slicks
Joined: Feb 2003
Posts: 2,529
Likes: 27
From: Auburndale Florida
2025 C2 of the Year ('64-'66) Finalist - Unmodified
St. Jude Donor '03-'05-'06-'07-'09
I had installed PI on a 72 Vette I had years ago. Greatly improved the idle quality.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
Are you feeding the Pertronix with 12vdc when in the "run" mode? The standard ignition system lowers the coil supply voltage to 8-9 volts [via the resistance wire built into the harness]. If you are using the existing coil supply wire, you won't have enough voltage for it to function well. You will need to run a direct line from the "run" contact on the ignition switch, or [downstream] at the firewall junction block in order to get the full 12vdc.
Melting Slicks
Joined: Mar 2005
Posts: 2,838
Likes: 10
From: Austin TX
Agree with the above; run the full 12v to the coil. But you need to run a coil designed for 12v; If you run a full 12v to a stock coil, you'll be replacing coils pretty regularly.
You can pull 12v from the fuse box. There's a port marked "IGN". It's as if Chevy knew we'd be making this mod decades later.
Good luck!
You can pull 12v from the fuse box. There's a port marked "IGN". It's as if Chevy knew we'd be making this mod decades later.
Good luck!
Last edited by 73, Dark Blue 454; Apr 6, 2009 at 11:39 PM.
Thread Starter
Melting Slicks
Joined: Feb 2003
Posts: 2,529
Likes: 27
From: Auburndale Florida
2025 C2 of the Year ('64-'66) Finalist - Unmodified
St. Jude Donor '03-'05-'06-'07-'09
I remembered some previos posts on the voltage issue, I checked the voltage, in the run or key on position, and metered 11.8 volts at the coil. Not my ca but wiring looks stock. Had PI on another Vette years ago, ran fine with 10 volts, stock wiring!!! thanks
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Melting Slicks
Joined: Nov 2001
Posts: 2,668
Likes: 43
From: Eastern US XX
A sick Pertronix CERTAINLY CAN make the car run like the timing is all messed up! It doesn't necessarily have to be a "work or not" failure.
When mine failed, it sounded exactly like I had a couple of wires crossed. Popping, flames out the carb, the works! Barely idled and ANY throttle would cause it to backfire and quit. Fortunately, I had a set of points and a condenser with me. Installed the poionts in place of the Pertronix and it has been running great ever since.
If you are chasing poor running, put in a new set of points and condenser and work from there. Once you get it running well, throw the Pertronix back in to see what happens.
When mine failed, it sounded exactly like I had a couple of wires crossed. Popping, flames out the carb, the works! Barely idled and ANY throttle would cause it to backfire and quit. Fortunately, I had a set of points and a condenser with me. Installed the poionts in place of the Pertronix and it has been running great ever since.
If you are chasing poor running, put in a new set of points and condenser and work from there. Once you get it running well, throw the Pertronix back in to see what happens.
Thread Starter
Melting Slicks
Joined: Feb 2003
Posts: 2,529
Likes: 27
From: Auburndale Florida
2025 C2 of the Year ('64-'66) Finalist - Unmodified
St. Jude Donor '03-'05-'06-'07-'09
A sick Pertronix CERTAINLY CAN make the car run like the timing is all messed up! It doesn't necessarily have to be a "work or not" failure.
When mine failed, it sounded exactly like I had a couple of wires crossed. Popping, flames out the carb, the works! Barely idled and ANY throttle would cause it to backfire and quit. Fortunately, I had a set of points and a condenser with me. Installed the poionts in place of the Pertronix and it has been running great ever since.
If you are chasing poor running, put in a new set of points and condenser and work from there. Once you get it running well, throw the Pertronix back in to see what happens.
When mine failed, it sounded exactly like I had a couple of wires crossed. Popping, flames out the carb, the works! Barely idled and ANY throttle would cause it to backfire and quit. Fortunately, I had a set of points and a condenser with me. Installed the poionts in place of the Pertronix and it has been running great ever since.
If you are chasing poor running, put in a new set of points and condenser and work from there. Once you get it running well, throw the Pertronix back in to see what happens.
The car will run, accelerate, no popping or backfiring. Just has a terrible idle and and has poor or lazy acceleration. Car has had 3 carb changes with little improvement. Feels more like a dead cylinder to me....could be bad wires. I need to try some test plug wires and replace the plugs. Just have to find some time!!!
Intermediate
Joined: May 2009
Posts: 39
Likes: 0
From: Oshawa Ontario
Is this staement true about the resistor wire, ie is it there and if so where is it located. Would it not be easier to just remove this resistor , than run a separate "non stock" wire to a fuse box.
If measured voltage is the same from original coil wire and say another source at the fuse box, does that mean there is no resistor in line and no separate wire needed?
If measured voltage is the same from original coil wire and say another source at the fuse box, does that mean there is no resistor in line and no separate wire needed?
Melting Slicks
Joined: Feb 2001
Posts: 3,330
Likes: 13
From: Europe , Luxembourg
Hi
I do not remember that my Petronix instructions mentioned anything about using unresited 12 Volts for supply.
I used the old coil ( not Petronix one ) and do not see why I should run it on higher Voltage now.
The Petronix unit only replaces the points contactor, not more.
It is not a HEI system that regulates the Voltage internally.
I am running the Pertronix for 4 Summer now with no issues, on resited Voltage supply like original .
Rgds. Günther
I do not remember that my Petronix instructions mentioned anything about using unresited 12 Volts for supply.
I used the old coil ( not Petronix one ) and do not see why I should run it on higher Voltage now.
The Petronix unit only replaces the points contactor, not more.
It is not a HEI system that regulates the Voltage internally.
I am running the Pertronix for 4 Summer now with no issues, on resited Voltage supply like original .
Rgds. Günther
Last edited by WESCH; Jul 27, 2009 at 01:00 PM.
Burning Brakes
Joined: Oct 2003
Posts: 1,090
Likes: 74
From: New Carlisle IN
Is this staement true about the resistor wire, ie is it there and if so where is it located. Would it not be easier to just remove this resistor , than run a separate "non stock" wire to a fuse box.
If measured voltage is the same from original coil wire and say another source at the fuse box, does that mean there is no resistor in line and no separate wire needed?
If measured voltage is the same from original coil wire and say another source at the fuse box, does that mean there is no resistor in line and no separate wire needed?
Tech Contributor
Joined: Jun 2004
Posts: 20,860
Likes: 959
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Is this staement true about the resistor wire, ie is it there and if so where is it located. Would it not be easier to just remove this resistor , than run a separate "non stock" wire to a fuse box.
If measured voltage is the same from original coil wire and say another source at the fuse box, does that mean there is no resistor in line and no separate wire needed?
If measured voltage is the same from original coil wire and say another source at the fuse box, does that mean there is no resistor in line and no separate wire needed?
Unless the ignition module has some sophisticated electronics in it, you'll need to retain the resistance wire to limit the coil current. The module may need a separate wire to the fuse box to get a clean 12 volt supply. It's up to you and the supplier directions to decide that.
Melting Slicks
Joined: Feb 2001
Posts: 3,330
Likes: 13
From: Europe , Luxembourg
Hi
They are speaking nonsense.
What you are writing might be true the way you interpret it, but the coil is a resistor and you add a resistor wire in series to it. This will reduce the Voltage . ( to exactly 6 Volts if both resistors are equal , wire & coil ).
That is how I passed school.
Of course also the current is limited this way.
But this discussion is not the first one about this. Anyway, I agree with sticking to the instructions from the manufacturers and the one of my coil wants it connected to the resistor , not full charging Voltage.
Rgds. Günther
They are speaking nonsense.
What you are writing might be true the way you interpret it, but the coil is a resistor and you add a resistor wire in series to it. This will reduce the Voltage . ( to exactly 6 Volts if both resistors are equal , wire & coil ).
That is how I passed school.
Of course also the current is limited this way.
But this discussion is not the first one about this. Anyway, I agree with sticking to the instructions from the manufacturers and the one of my coil wants it connected to the resistor , not full charging Voltage.
Rgds. Günther
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
Try grounding the points mounting plate in the distributor through the points adjusting window to the engine block. If the grounding wire below the points plate that grounds it to the distributor body is broken (not uncommon) the ignition will not allow the coil to reach full saturation voltage and cause the condition you describe. Also if it is an older version of the Ignitor, the rivets holding it together can loosen up if there was improper clearance to the distributor magnet ring (from being hit by the ring) and will again cause voltage problems. I just helped a friend who is a professional marine mechanic "fix" an Ignitor in a 351 Ford powered boat (new Ignitor installation), the distributor housing had so much corossion between the housing and the engine block that it wouldn't properly ground the ignition voltage (pulled the distributor out, cleaned the block and housing and "solved" the problem.) Also check coil polarity for proper connection to "+" and "negative" terminals.
Tech Contributor
Joined: Jun 2004
Posts: 20,860
Likes: 959
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Hi
They are speaking nonsense.
What you are writing might be true the way you interpret it, It doesn't matter what my "interpretation" is, or what I would like it to be. It's what physics and circuit theory says. but the coil is a resistor No, it's an inductor, with some unavoidable winding resistance. A big difference! The only time a resistor and the coil (inductor) are remotely similar is when the engine isn't turning. Once the engine is started, their personalities are very different. and you add a resistor wire in series to it. This will reduce the Voltage . ( to exactly 6 Volts if both resistors are equal , wire & coil ).
That is how I passed school. It wasn't an engineering school, I'm assuming.
Of course also the current is limited this way. It's not "also", it's the only function of the ballast resistance.
But this discussion is not the first one about this. That's correct. Apparently you've chosen not to accept the previous corrections. Anyway, I agree with sticking to the instructions from the manufacturers and the one of my coil wants it connected to the resistor , not full charging Voltage.
Rgds. Günther
They are speaking nonsense.
What you are writing might be true the way you interpret it, It doesn't matter what my "interpretation" is, or what I would like it to be. It's what physics and circuit theory says. but the coil is a resistor No, it's an inductor, with some unavoidable winding resistance. A big difference! The only time a resistor and the coil (inductor) are remotely similar is when the engine isn't turning. Once the engine is started, their personalities are very different. and you add a resistor wire in series to it. This will reduce the Voltage . ( to exactly 6 Volts if both resistors are equal , wire & coil ).
That is how I passed school. It wasn't an engineering school, I'm assuming.
Of course also the current is limited this way. It's not "also", it's the only function of the ballast resistance.
But this discussion is not the first one about this. That's correct. Apparently you've chosen not to accept the previous corrections. Anyway, I agree with sticking to the instructions from the manufacturers and the one of my coil wants it connected to the resistor , not full charging Voltage.
Rgds. Günther
Burning Brakes
Joined: Dec 2007
Posts: 952
Likes: 0
Hi
They are speaking nonsense.
What you are writing might be true the way you interpret it, but the coil is a resistor and you add a resistor wire in series to it. This will reduce the Voltage . ( to exactly 6 Volts if both resistors are equal , wire & coil ).
That is how I passed school.
Of course also the current is limited this way.
But this discussion is not the first one about this. Anyway, I agree with sticking to the instructions from the manufacturers and the one of my coil wants it connected to the resistor , not full charging Voltage.
Rgds. Günther
They are speaking nonsense.
What you are writing might be true the way you interpret it, but the coil is a resistor and you add a resistor wire in series to it. This will reduce the Voltage . ( to exactly 6 Volts if both resistors are equal , wire & coil ).
That is how I passed school.
Of course also the current is limited this way.
But this discussion is not the first one about this. Anyway, I agree with sticking to the instructions from the manufacturers and the one of my coil wants it connected to the resistor , not full charging Voltage.
Rgds. Günther
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
The resistance wire is built into the harness, so you can't just remove it. There is no 'resistor' in the system [since mid-60's cars]. You can bypass the resistor wire with another that is run from the IGN junction on the fuse block...or you can buy a Crane electronic unit that is made to run with the standard wiring system & coil OR with 12vdc directly.
Le Mans Master
Joined: Jun 2008
Posts: 5,284
Likes: 235
From: Rockledge FL
Hi
I do not remember that my Petronix instructions mentioned anything about using unresited 12 Volts for supply.
I used the old coil ( not Petronix one ) and do not see why I should run it on higher Voltage now.
The Petronix unit only replaces the points contactor, not more.
It is not a HEI system that regulates the Voltage internally.
I am running the Pertronix for 4 Summer now with no issues, on resited Voltage supply like original .
Rgds. Günther
I do not remember that my Petronix instructions mentioned anything about using unresited 12 Volts for supply.
I used the old coil ( not Petronix one ) and do not see why I should run it on higher Voltage now.
The Petronix unit only replaces the points contactor, not more.
It is not a HEI system that regulates the Voltage internally.
I am running the Pertronix for 4 Summer now with no issues, on resited Voltage supply like original .
Rgds. Günther
the ignitor II says in the instructions it requires 12v constant.
the ignitior I doesnt need the full 12.