Ignition coil

[yellowmach351]

Need help from an ignition guy. I have a 71 Mach1, 351c, 4speed, that I ordered from the factory in April of 1971. I have the engine on my test stand after a rebuild with some speed parts and a freshening up. I put in a Pertronix ignition module. Red wire, along with a 12v source wire from the ignition, to the + side of coil and the black wire from the module to the - side of coil, per the instructions. Since I am not using the wiring harness that still resides in the car, what do I need to hook up to the - side of the coil? They do not address that in the instructions as they more than likely believe it's just a simple swap in the car, or that the person doing the work is smarter than me! Is it another 12v source? I obviously have no spark when I crank it over. I know this is a silly question, but I am trying to be very careful and not hook up something incorrectly and blow the module.

Thanks for any help guys.

 

[Don C]

Is your breaker plate ground wire still connected? I believe the metal base plate of the Pertronix needs to be grounded.

 

[yellowmach351]

Yes it is grounded.

 

[SteveO_71]

Need help from an ignition guy. I have a 71 Mach1, 351c, 4speed, that I ordered from the factory in April of 1971. I have the engine on my test stand after a rebuild with some speed parts and a freshening up. I put in a Pertronix ignition module. Red wire, along with a 12v source wire from the ignition, to the + side of coil and the black wire from the module to the - side of coil, per the instructions. Since I am not using the wiring harness that still resides in the car, what do I need to hook up to the - side of the coil? They do not address that in the instructions as they more than likely believe it's just a simple swap in the car, or that the person doing the work is smarter than me! Is it another 12v source? I obviously have no spark when I crank it over. I know this is a silly question, but I am trying to be very careful and not hook up something incorrectly and blow the module.

Thanks for any help guys.

I believe those are the only connections that are needed. As mentioned, there should be a ground wire in the distributor.

Is the spacing correct with the magnetic pickup unit?

Bad Pertronix module? Maybe switch back to points to rule out a Pertronix issue.

 

[yellowmach351]

Thanks guys. Yesterday I checked the spacing and it was at .030 per the little plastic spacer that comes with the module.I thought about putting the old points back in and even laid them back on my workbench, but didn't do it yet. I didn't want to pull the distributor again in case I was off a tooth or two. I don't think being off makes any difference on electronic ignition since you aren't relying on the points to have to open exactly at the top of the dwell. As long as the rotor is pointing at #1 when it's on TDC it should be good....agree, or am I wrong about that? Could be a bad module. Wouldn't surprise me considering I also had to replace a new, never used, electric fuel pump on my test stand yesterday. Day wasn't going well!

 

[jbojo]

Here's an installation video, installation starts at about the 2:20 point. Sounds like you did it right though.

http://www.bing.com/videos/search?q=how+to+wire+a+pertronix+ignitor&view=detail&mid=FB7ACE3D1B2DB11EC233FB7ACE3D1B2DB11EC233&FORM=VIRE

 

[Don C]

Yes, as long as the rotor points to the #1 distributor post when the engine is at TDC on the compression stroke you are fine. Even if it were off the Pertronix should create a ground for the negative side of the coil and release the ground when the lobe passes the module, creating a spark from the coil. You should be able to put the points back in without pulling the distributor.

How did you determine that you don't have a spark?

Have you measured the voltage on the + terminal of the coil, when the switch is on, to make sure you have 12 - 13 volts?

 

[yellowmach351]

I have a tester that is used to test for spark in the plug wires. One end is grounded and the other end has a slot, as wide as the plug wire. That is slid down the wire while engine is being cranked and if there is a spark, a light will flash. No flash, according to my buddy that was manning the tester. Maybe I just need to pull the plug and ground it to make sure. BUT, regardless, it didn't even attempt to fire....and I have gas to the carb. One good thing about these old engines, no electronics. If it don't run, it's either gas or spark.

Before I even tried to start it, I did measure voltage at the + terminal and it is a good 12v.

 

[Don C]

In that case I would suspect the Pertronix is bad.

 

[yellowmach351]

I am leaning that way also. If I don't discover something tomorrow, I am going to call Pertronix on Tuesday and discuss with them. Thanks to all for the help, and I will advise an outcome.

 

[yellowmach351]

Finally got back to this after the long weekend. Pertronix module tested good. It almost had to be timing so I pulled all the plugs and turned over by hand until I was on compression for #1. Feeling kind of foolish. Did the ultimate screw up......distributor was 180 degrees off. It was perfectly timed in the beginning. It came off TDC when I was torquing the flywheel. It must have turned a complete revolution and not 1/2 like I thought, so when I brought it back to where I THOUGHT it was supposed to be, bingo...180 off. NEVER, NEVER, NEVER guess!!!!

Thank all of you for your input. Glad to know you are out there and willing to offer your help.

 

[yellowmach351]

By the way, it runs great.