Electronic ignition

[Jakes1968]

Hello there. I've been reading on here about electronic ignitions and my 68 has one that was on it when I bought it. But what's confusing me is where they mention taking the [+] cable from the distributor and splicing into a switch wire? The reason I'm asking is because the previous owner joined it at the (+) post of the coil with the yel. Starter wire and the brown cloth/white wire and it was getting so hot you could see smoke. i do have a service manual and traced some wires back. But I'm still puzzled could anyone shine a little clarity on this for me.

[Scott V]

what kind of electronic ignition do you have? different ones are wired differently.

a switched wire is something that has 12volt when you turn the key *on*.

the (+) post of the coil doesnt have 12 volt.........it has a ballast resistance wire in it to lower the voltage.........the cloth covered wire you talk about in your post.

-Scott V.

[Jakes1968]

Thanks for the reply Scott. It is a protronix flamethrower 1.5 ohm coil with a protronix igniter module it has 21w-v4 sticker on top of it. If it needs a switched wire to the module which wire do I use? Does it matter, as long as it's switched? Also what is the desired voltage drop with the ballast wire?
Thanks again jake

[Scott V]

if you dont have a shop manual for your car.........get one....youll need it to fix your car & it will help you alot in figureing out what wire does what/etc.

heres the instructions for your pertronix ignitor http://www.pertronix.com/docs/instructi ... 01162A.pdf

-Scott V.

[66vairguy]

Hmmmm - Jake - The coil "+" terminal should only have the yellow wire from the starter harness. Yes some folks put the Petronix power supply wire on the coil "+" terminal. It's not recommended, but it works in temperate climates were the battery voltage doesn't drop much during starting.

FIRST YOU NEED TO DETERMINE IF YOU HAVE A PETRONIX MODULE OR THE PETRONIX II MODULE. They are wired differently. Without knowing which you have it's difficult to explain the wiring.

The Petronix module should use a 1.5 ohm coil. The Petronix II can use either a Flamethrower I or the Flamethrower II coil which is a low 0.5 ohm and you DO NOT use a resistance wire.

If you run the Petronix II and the Flamethrower II 0.5 ohm coil the resistance wire will get HOT.

Don't feel too bad - folks usually don't install the Petronix correctly in the Corvair as the generic instructions aren't very helpful to the average person.

[Scott V]

FIRST YOU NEED TO DETERMINE IF YOU HAVE A PETRONIX MODULE OR THE PETRONIX II MODULE. They are wired differently. Without knowing which you have it's difficult to explain the wiring.

i think both are wired the same. red to switched 12v & black to coil [-]

-Scott V.

[66vairguy]

FIRST YOU NEED TO DETERMINE IF YOU HAVE A PETRONIX MODULE OR THE PETRONIX II MODULE. They are wired differently. Without knowing which you have it's difficult to explain the wiring.

i think both are wired the same. red to switched 12v & black to coil [-]

-Scott V.

Power is hooked up the same, BUT the Petornix II ONLY when used with the Flamethrower II coil DOES NOT USE the resistance wire to the coil (BALLAST) - coil "+" goes directly to switched 12VDC. If you install a Flamethrower II coil with the regular Petronix module then you have problems. Seen it done numerous times. Sadly a lot of Petronix installations are done incorrectly leading to short life and complaints. When the proper components are used AND installed correctly the Petronix is reliable. The GM resistance wire in the harness (ballast) seem to confuse folks.

[Jakes1968]

Both of mine is the gen 1. But thanks guys for all the info. I jumped the red module wire to the key and fired right up no smoke! A little warm but I figure it shud be since it's a resistor, right?

[Jakes1968]

Also 66vairguy my resistance wire is soldered to the clip at the coil with my yellow wire... is that not normal

[66vairguy]

Also 66vairguy my resistance wire is soldered to the clip at the coil with my yellow wire... is that not normal

According to the 68 wiring diagrams - NO. Of course in 68 things on the assembly line were getting odd, but I doubt they would have modified an engine harness. Also the resistance wire CANNOT be soldered, it must be crimped only. So something is odd with your wiring.

Yes the resistance wire gets warm. In the old days the ballast resistor was wirewound in a ceramic holder and it got HOT so it had to be mounted carefully. GM simply went to a longer wire with the same resistance to spread out the thermal area - less heat per inch, no ceramic holder to mount. So the resistance wire is long and it was simply routed around in the engine wiring harness in a loop. The resistance wire is brittle and occasionally it breaks. Someone may have tried a repair on yours. As stated before the cloth wire goes from the bulkhead connector to the stater harness plug connector. Different cars used different ballast values. The Corvair ballast (resistance wire) total is 1.8ohms +/- 0.01ohm and yes you need a very good ohm meter to measure it accurately.

If all else fails Clark's sells the engine harness which includes the resistance wire. It's a common replacement harness since the wiring in that part of the car really takes a beating. Also order the short wiring harness from the engine harness small plug to the starter as that one is usually in poor shape. You'll also get all new taillamp sockets as part of the harness that are MUCH better than the replacement junk sold at auto parts stores.

[66vairguy]

Also 66vairguy my resistance wire is soldered to the clip at the coil with my yellow wire... is that not normal

According to the 68 wiring diagrams - NO it's not correct. Of course in 68 things on the assembly line were getting odd, but I doubt they would have modified an engine harness. Also the resistance wire CANNOT be soldered, it must be crimped only. So something is odd with your wiring.

Yes the resistance wire gets warm. In the old days the ballast resistor was wirewound in a ceramic holder and it got HOT so it had to be mounted carefully. GM simply went to a longer wire with the same resistance to spread out the thermal area - less heat per inch, no ceramic holder to mount. So the resistance wire is long and it was simply routed around in the engine wiring harness in a loop. The resistance wire is brittle and occasionally it breaks. Someone may have tried a repair on yours. As stated before the cloth wire goes from the bulkhead connector to the stater harness plug connector. Different cars used different ballast values. The Corvair ballast (resistance wire) total is 1.8ohms +/- 0.01ohm and yes you need a very good ohm meter to measure it accurately.

If all else fails Clark's sells the engine harness which includes the resistance wire. It's a common replacement harness since the wiring in that part of the car really takes a beating. Also order the short wiring harness from the engine harness small plug to the starter as that one is usually in poor shape. You'll also get all new taillamp sockets as part of the harness that are MUCH better than the replacement junk sold at auto parts stores.

[Jakes1968]

Also 66vairguy my resistance wire is soldered to the clip at the coil with my yellow wire... is that not normal

According to the 68 wiring diagrams - NO it's not correct. Of course in 68 things on the assembly line were getting odd, but I doubt they would have modified an engine harness. Also the resistance wire CANNOT be soldered, it must be crimped only. So something is odd with your wiring.

Yes the resistance wire gets warm. In the old days the ballast resistor was wirewound in a ceramic holder and it got HOT so it had to be mounted carefully. GM simply went to a longer wire with the same resistance to spread out the thermal area - less heat per inch, no ceramic holder to mount. So the resistance wire is long and it was simply routed around in the engine wiring harness in a loop. The resistance wire is brittle and occasionally it breaks. Someone may have tried a repair on yours. As stated before the cloth wire goes from the bulkhead connector to the stater harness plug connector. Different cars used different ballast values. The Corvair ballast (resistance wire) total is 1.8ohms +/- 0.01ohm and yes you need a very good ohm meter to measure it accurately.

If all else fails Clark's sells the engine harness which includes the resistance wire. It's a common replacement harness since the wiring in that part of the car really takes a beating. Also order the short wiring harness from the engine harness small plug to the starter as that one is usually in poor shape. You'll also get all new taillamp sockets as part of the harness that are MUCH better than the replacement junk sold at auto parts stores.

Here's what mine looks like it looked factory I was wrong it wasn't soldered. But it's a white wire that comes out the multi plug and run up towards the inside tail/stop light crimps to the cloth wire (had a tat like cover over it) the runs past the coil and loops back and joins with the starter wire.

[County98]

Good tip about engine harness coming with tail lamp sockets. I didn't know that and a couple of mine are shot. Thanks!

Sent from my SAMSUNG-SM-G870A using Corvair Forum mobile app

[bbodie52]

• NOTE: REMOVE OR BYPASS EXTERNAL BALLAST RESISTOR OR RESISTANCE WIRE WHEN INSTALLING THE RECOMMENDED FLAME-THROWER COIL.
• Do NOT remove the ballast resistor or resistance wire if the primary resistance is lower than specified or if you are using the stock coil.
• Pertronix Ignitor Operating Voltage: 8-V to 16-V DC

REASONS FOR THE ABOVE GUIDELINES...
The Pertronix Flame Thrower coil is promoted as a high output (40,000 Volt) canister coil. Their chart recommends bypassing the ballast resistor or resistor wire in the GM configuration so that the coil will be powered with a full 12 VDC --- not with the reduced nominal 7 VDC provided to the factory coil after passing through the resistor wire. This allows the coil to produce the full advertised 40,000 volts. The reason GM powers the stock Corvair coil with only 7 VDC is to let the coil run at a cooler temperature, which will happen with less supply voltage. This lower coil voltage also prolongs the life of the stock ignition points.

The Pertronix chart shows a recommended supply voltage of 12 VDC, BUT it also recommends a 1.5 ohm coil for a V8 engine, and a 3.0 ohm coil for use with a 6 or 4 cylinder engine. The reason is likely the duty cycle applied to the coil with more engine cylinders. The coil functions with an ON/OFF cycle as the distributor switches it on to charge, and off to discharge through the spark plugs. An 8 cylinder engine fires the coil more times per engine revolution, so the more frequent ON/OFF cycle allows the coil windings to cool (OFF) more times per engine revolution than it would when supporting a 6 or 4 cylinder engine. The longer duration of the ON (charging) period in a coil supporting only 6 or 4 cylinders would cause the coil to be exposed to more heat buildup. By recommending a 3 ohm coil for use with the 6 or 4 cylinder engines, the amount of current flow with 12 VDC power is reduced to ½ the current seen by a 1.5 ohm coil. This lower current also helps the coil to run at a cooler temperature. So a 3.0 ohm coil is more appropriate for use with a 6 or 4 cylinder engine.

A 40,000 volt coil is also overkill for the low-revving, low compression ratio Corvair engine. The turbocharged Corvair engine might benefit from the "hotter" spark voltage because of the higher combustion chamber pressures, but even with the turbo engine it is overkill. Since your coil is a 1.5 ohm coil, it may run hot when used on the Corvair six cylinder engine. If you leave the factory ballast resistor (1.8 ohms) in the circuit, the two together (1.8 ohms resistor wire plus 1.5 ohms Flamethrower coil) will give you a primary circuit with a nominal 3.3 ohms, which is close to the recommended primary circuit resistance of 3.0 ohms recommended by Pertronix. (The Chevrolet stock coil has an internal primary resistance of 1.28 - 1.42 ohms) So leave the resistor wire in the circuit with your 1.5 ohm coil. If you had a 3.0 ohm coil, the resistor wire should be removed.

=========================================================================================

The needs of the Pertronix Ignitor module in the distributor are a different issue. Pertronix recommends 8.0 - 16 VDC to power this electronic module. With a resistor wire in the circuit, you will providing only a nominal 7 VDC to the electronic circuits in the module, which is slightly below the minimum standard. Because of this, the reduced voltage you will have at the coil positive terminal is inadequate to power the Pertronix module (via the RED wire). For the Pertronix Ignitor module in the distributor, you should splice into the power wire controlled by the ignition switch at a point just BEFORE the multi-connector (the firewall side of the wiring harness).

By way of explanation, if you look at the schematic diagram below, locate the ignition coil positive terminal and trace the wire (labeled 20 B/Y). This wire travels back to a two pin plastic connector, where it is connected to TWO WIRES. The 20 B/Y wire on the other side of the plastic connector goes to the starter solenoid. This provides a full 12 VDC to the coil when the starter solenoid is engaged and the engine is being cranked. When the key is released, the starter solenoid is disengaged and the 12 VDC coming from the solenoid is cut off. This leaves only the nominal 7 VDC coming from the other wire (labeled 20 W/R/B), which is the resistor wire.

On the other side of the 12-pin plastic multi-connector, the wire connected to the resistor wire is labeled 20 B/P (20 gauge Black/Purple Stripe). This wire carries a full 12 VDC provided by the ignition switch when the key is ON. This is where you would splice in a new wire to power the Pertronix Ignitor module in the distributor. In this configuration the coil would receive 12 VDC from the starter solenoid when cranking the engine (temporary hotter spark voltage to help start a cold engine), and a reduced 7 VDC for normal running and a cooler coil operation. At the same time, the Pertronix Ignitor module would receive a full 12 VDC as long as the engine is running, which it needs for the internal electronic circuitry to operate properly.

NOTE THAT THE WIRING COLOR CODES ON YOUR 1968 CORVAIR MAY BE DIFFERENT FROM THE WIRING SHOWN IN THE 1965 WIRING DIAGRAM.

I hope that this somewhat lengthy explanation helps you to understand the reason for powering the Ignitor module separately from the power provided to the Flamethrower coil. Both are powered by the switched power from the ignition switch, but the coil needs the ballast resistor in the circuit, while the Pertronix electronic module needs the resistor wire out of the circuit to provide it with adequate voltage. (In a stock configuration with ignition points, the resistor wire is needed by the coil AND the points, to reduce the voltage applied to the points to reduce arcing and burning as the switching points open and close -- controlling power through the coil. Without the resistor wire the coil would run hot and the points would burn and wear out more rapidly).

The additional diagrams may be helpful in visualizing the Pertronix wiring...

1965-1969 Corvair Engine Compartment Wiring Harness Multi-pin Connector.jpg (33.79 KiB) Viewed 1211 times

1965-1969 Corvair Engine Compartment Wiring Harness Starter Connections.jpg (80.88 KiB) Viewed 1211 times

[66vairguy]

Sorry Brad, while I appreciate all your contributions to this forum your advice on the Petronix coil is incorrect. I've run into this issue many times while sorting out Corvair/Petronix installations. Not really your fault, I blame the the POOR instructions from Petronix. Yes a 4 and 6 cylinder engine have a different ignition duty cycle, but the Petronix vague coil recommendations are based on the fact a lot of old cars with 6 cylinder engines DID NOT USE A BALLAST ignition system. So yes a 3 ohm coil would be used without a ballast. Also VW used a 3.0 ohm coil (no ballast) on their older air cooled cars. So basically the Petronix coil chart is not applicable to the Corvair "6". Yes you can eliminate the ballast and go with a 3 ohm coil, but you loose the ballast by-pass that optimizes cold starting resulting in an inferior starting voltage at the spark plug. In warm climates it probably won't be an issue.

The Corvair was designed to use a ballast ignition system from it's beginning. The ballast wire is 1.8 ohm +/- 0.1 ohm and the 65 Corvair coils specs. are 1.35 ohm +/- 0.7 ohm (provides a total impendance that is at least 3.0 ohms). Very similar to the V8 Chevrolet cars of the era. The 1.5 ohm Petronix coil isn't the best match for the basic Petronix Ignitor, but it works for non-turbo engines. I usually tell folks the best non-turbo setup on a Corvair is the basic Ignitor with a STOCK coil (with Corvair ballast wire intact). A reasonable replacement for the original Corvair coil is the the generic Chevy SBC V8 coil (all the specialized Delco coils are no longer available). It should be noted this explanation is for the Petronix Ignitor.

The Petronix Ignitor II uses a scheme (undisclosed) to limit current to the coil (GM's HEI uses two different dwell values, one for lower RPM, one for higher RPM to limit coil amperage at low RPM, yet provide adequate coil charge times at higher RPM). This allows them to use a low impedance 0.5 ohm coil powered WITHOUT a ballast limiting amperage. The problem with BOTH the Ignitor and Ignitor II is they use a dwell tyical of a V8 and while this is not an issue with the Ignitor, it has been documented that the Ignitor II circuit mis-fires around 600 - 700 RPM (Corvair PG in drive) because I suspect it's circuit was designed for a V8 which of course has more trigger pulses at 600 RPM than the Corvair 6.

By now folks are thinking the Petronix system is not optimal, but experience shows it does the job and is low maintenance. Remember from the moment stock ignition points are installed they wear and dwell and timing shift. So there is some tolerance for variation from optimum.

[bbodie52]

Sorry Brad, while I appreciate all your contributions to this forum your advice on the Petronix coil is incorrect. I've run into this issue many times while sorting out Corvair/Petronix installations. Not really your fault, I blame the the POOR instructions from Petronix. Yes a 4 and 6 cylinder engine have a different ignition duty cycle, but the Petronix vague coil recommendations are based on the fact a lot of old cars with 6 cylinder engines DID NOT USE A BALLAST ignition system. So yes a 3 ohm coil would be used without a ballast. Also VW used a 3.0 ohm coil (no ballast) on their older air cooled cars. So basically the Petronix coil chart is not applicable to the Corvair "6". Yes you can eliminate the ballast and go with a 3 ohm coil, but you loose the ballast by-pass that optimizes cold starting resulting in an inferior starting voltage at the spark plug. In warm climates it probably won't be an issue.

I DISAGREE.

Many older vehicles (1950s vintage, for example) did use a ballast resistor. In any case, the Pertronix instructions are recommending a full 12 VDC voltage feed to all of their high output coils, and those listed on the chart begin with the assumption that any ballast resistor or resistor wire in the vehicle primary ignition wiring has been eliminated as a basis for the Pertronix equipment installation. If one exists, Pertronix wants it removed or bypassed. Their recommendation chart assumes that all primary current control resistance is to be provided only by their coil internal primary winding, with 1.5 ohms for a V8 and 3.0 ohms for a 4 or 6 cylinder engine. (This sets the stage for proper support of both the Flame-Thrower coil and the Ignitor distributor electronic module — providing 12 VDC for both). Pertronix then compensates for differing engine configurations (8 cylinder vs. 6/4 cylinder) by recommending different high performance coils (1.5 ohm primary resistance for a V8, and 3.0 ohm primary resistance in the coil for a 6 or 4 cylinder engine). The 1.5 ohm primary winding coupled with a V8 engine short duty cycle and 12 VDC power source produces the advertised 40,000 volt secondary output to the spark plugs. The same coil connected to a 6 or 4 cylinder engine, with its longer duty cycle, would allow excessive primary charging duration — more than needed to attain a 40,000 volt output from the secondary winding. The results would be more heat buildup within the primary coil, which could shorten the life of the coil.

Switching to a 3.0 ohm coil primary resistance coupled with a 4 or 6 cylinder engine duty cycle would reduce the current flow, but the charging cycle for the primary would be lengthened by the longer 6/4 cylinder duty cycle, which again should reach the desired 40,000 volt secondary output because of the longer duty cycle expected with fewer cylinders. The reduced current with 3.0 ohms of primary resistance would keep the coil within designed heat parameters. The factory stock design configuration that switches to a high output voltage provided by the starter solenoid during cold start cranking would not be needed, because 12 VDC would be present at all times at the new high performance coil input, providing the advertised 40,000 volt high output to the spark plugs. The Pertronix Ignitor module would eliminate concern about rapid decay of the points contacts when subjected to 12 VDC.





NOTE: IN THE ABOVE CHART THERE IS SOME ROOM FOR CONFUSION, BECAUSE UNLIKE THEIR FIRST CHART THAT INDICATES "IGNITOR ONLY", THE SECOND CART INDICATES "IGNITOR OR POINTS" IN THE FIRST SECTION. The Flame-Thrower 3Ω coil would reduce the current that the points would be exposed to, so excessive point wear would be prevented.

Flame-Thrower II coils feature a super low resistance which make them the ideal coil for Ignitor II ignition systems as well as many other high energy ignitions. Low resistance and improved turns ratio help to produce up to 45,000 volts. This higher voltage enables you to run larger spark plug gaps for added power and better fuel economy.

These coils have internal windings that were designed to tolerate more heat with ultra-high current flow produced when coupling 12 VDC with only 0.6 ohms of internal primary resistance. The high switching current seen with such a coil would quickly destroy ignition points, and the Pertronix Ignitor internal circuitry was also not designed to tolerate this much primary current. The Ignitor II was beefed up with a switching transistor circuit and dwell control electronics that can tolerate the higher expected current when using a Flame-Thrower II coil. Connecting such a coil to a factory ballast resistor or resistor wire would not only cancel such a high output secondary voltage by reducing the primary current, but it would likely overheat the resistor wire or ballast resistor with an internal coil primary resistance of only 0.6 ohms, instead of the stock coil internal primary resistance of 1.28 - 1.42 ohms expected by engineers when they designed the factory wiring.

Of course I am making assumptions based on the technical specifications and installation instructions published by Pertronix. Many installation decisions are left to the installer, without really explaining why these different combinations of aftermarket ignition components and the variables seen in factory wiring may cause problems if the purchaser and installer doesn't understand the implications of incorrect wiring. Crane Cams, with their optical trigger ignition system, designed the electronics in the XR700 to operate with the lower expected voltage when the resistor is left in the circuit. (In fact, it can overheat if connected to 12 VDC). Their XR3000 is similar to the Pertronix Ignitor II in its high performance design that tolerates ultra-low resistance performance ignition coils.

The XR700 requires ballast resistance to limit coil current. The XR3000 is a high performance version with a computer chip that controls coil current and dwell. When installing an XR3000, all OE ballast resistance must be bypassed.

When in doubt, a phone call to Pertronix can clear things up...

Technical Assistance
440 East Arrow Highway
San Dimas, CA 91773
Phone: (909) 547-9058
Fax: (909) 599-6424