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Discussion Starter #1
i insalled thr petronox electronic ignition in my 70 thr instructions & mustang monthy says to by pass the pink resistor so the system would get a constant 12v but it starts and runs finds although it only gets driving around the neibord once in a while. do i really need to by pass the pink wire & what does it connect to & hoe do i by pass it
thanks,
curtisz​
 

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Pertronix I or II? Stock coil or Flamethrower coil?
 

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Discussion Starter #4
petronix 1 i guess box just says petronix ignitor. i assume the pink wire is in the steering column were does it go to originally? exactly what is it going to be by passing and what grade of wire to use an where will the igninition end connect to? i assume the coil end goes to the positive side of coil. it is a stock coil. will a flame thrower make much of a differnce? also how do i tell if my car 1970 351c has a ballast resistor and what is it also what is an hei type coil. i just connected red wire to pos. side of coil & black to neg. reconnected ground strap and it started an seems to run o.k. although i havent driven it much mainly just move it back & forth to move others around. also curious if you move the distributor back & forth will it still advanced,retard timing the same as points. the mustang monthly article says pink wire must be bypassed they ran a red wire from the petronix (positive side im guessing article did not specify) and connected it to the red/green stripe wire at ignition switch. it dosent say if there are 2 wires or 1 thats redw/green stripe. havent pulled ignition out yet to look. do i just tap into that wire or red or green if there are 2. and do i need to remove the pink wire or leave it as is.
the mustang article did suggest a flamethrower with 1.5 or 3.0 ohm primary resistance. which should i use. this has been on the car for a couple of years & i havent messed with it because it ran and i hate messing w/ electrical plus the instructions and article were a little vauge. no im not a dumbass just dont know much about elec. or have any meters or knowledge of how to use them. i know rust & floorpans and how to gut & reassemble. any more help much appreciated
 

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I have a '68, so I hope that this advice is OK for a '70. The pink wire comes from the ignition switch and connects with a bullet connnector to a single wire (I don't remember the color). I didn't like the idea of cutting into the wiring to get to a 12V source, so I made a short Y connector that fits between the pink and the 12V wire with a live pigtail to the side. In effect, it does the same thing as a splice but without any cutting. That way you are not doing anything that is irreversible.
 

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When I first installed my Pertronix spark trigger I had it connected to the coil + wire. In this configuration (connected to the resistor wire), the car would stop running or run badly once the resistance in the wire increased, reducing the voltage to the unit. I connected the Pertronix' red wire to a switched constant 12-volt source and haven't had a recurrence of the problem.
 

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If it is a Pertronix Ignitor I then 12 volts is not needed as per their instructions from 15 years ago. Both the Cougar and Mustang have been running a Pertronix I with stock yellow top coil and the stock wires for 15 years. The Park Lane, F100 and Polara all run a Ignitor II with Flamethrower 0.6 ohm coil and a 12 volt source. No car has ever presented a problem running in it's assigned configuration.
 

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The diagram on the the instructions was incorrect for cars with a resistance wire. Internally the transistors used to switch ground were, and still are, 12 volt devices. The Ignitor will work with reduced voltage, and it is a compliment to your maintenance skills that yours are still working well. One other factor is that the tach in the XR7 is also in series and is an additional source of voltage drop, so standards tend to actually work a little better than XR7s when using the coil wire for power.

Several years ago I spoke with an engineer at Pertronix about why they didn't use a lower voltage device and regulate the power supply, so it would work in any event. He said the required components would not fit in the space available and that the lower voltage devices were less durable than the 12 volt devices. He also suggested that a good fix was to replace the resistance wire with regular wire, and ad a ballast resistor under the hood. Pick up power for the Pertronix upstream of the resistor.
 

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OK, now you lost me, why would you replace the resistor wire and then add a ballast resistor when the only reason for a resistor is for points which you are replacing?
 

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Expediency. He was saying that if you did that you would have a place to grab the 12 volts you need for the Pertronix from a convenient location. You use the resitance wire to pull the replacement wire through the fire wall.
 

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The coil needs to be powered through the resistor wire. If you bypass the wire and supply full 12 volts to the coil, the coil is fried and the tach reads too high. That is why you need to have a separate 12 volts to the Pertronics II red wire.

I've run the Pertronics 1 units for over 20 years with the power coming only from the coil + resistance wire. It has not been a problem. The Pertronics II - a different device, and they don't like anything less than 12 volts.

OK, now you lost me, why would you replace the resistor wire and then add a ballast resistor when the only reason for a resistor is for points which you are replacing?
 

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Discussion Starter #14
its just pertronix ignitor on the side of the box it says operating voltage 8v-16v dc coil resistance 1.5 ohms or more since it says 8v-16v could it be alright wired like it is someone said earlier that they would work better last longer with 12v is that the main reason or will the car actually run better and how do i check the resistance of the coil? i do floorpans not electrical. i dont want to mess with the wiring unless i have to especially since the 70 has the locking column and column switch, not a lot of fun to get to. also i know by moving the distributor its changing the timing ( have timing light never tried to us one just set by ear) my question is is it changing the same as points would you affect the gap of the points when moving dist. but the electronic is locked in place is it changing by how close the high spot of the lobe is to the pertronix? the car sat for 12 years before i got it i dont remeber if there was any thing in gas tank or not i dont think so but if there was i would of drained it. i have a new carb the car starts easy but runs rough also put new timingchain in, the single exhaust i cut off above the h-pipe cause it was rusted out do you think the car might run smoother once it has an exhaust system i plan to take it in and have all new duals run from the exhaust manifolds back will it run better once it has a little back pressure?
 

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The way to check a ign. coil, you will need a volt ohm meter, you can get cheap ones or expensive ones, they will both do the job. Primary circuit set meter on 200 range red lead to + (pos.)on coil and black on neg, should be 0.3 to 2.0. Secondary circuit set meter to 200K black to neg , red to coil wire post, should be 6.0 to 30.0 K.
Cutting the exhaust off should not hurt idle until you get new ones.
 

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Discussion Starter #16
The way to check a ign. coil, you will need a volt ohm meter, you can get cheap ones or expensive ones, they will both do the job. Primary circuit set meter on 200 range red lead to + (pos.)on coil and black on neg, should be 0.3 to 2.0. Secondary circuit set meter to 200K black to neg , red to coil wire post, should be 6.0 to 30.0 K.
Cutting the exhaust off should not hurt idle until you get new ones.
thanks for the help
 

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I burnt up 2 pertronix setups because my ignition switch was going bad. It eventually smoked and I had to change the switch. That can suck on a 70 as it is a 1 year only switch. I used a 71-73 switch, with my 70 harness. It took a little cutting and soldering but it stopped my loss of voltage problem going to the ignition. I also ditched the pertronix for a HEI distributor.

Here is a link to my adventures with the ignition switch. http://www.mercurycougar.net/forums/showthread.php?56887-1970-Cougar-Ignition-Switch-Fix
 
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