Questions on voltage to the coil

[383man]

You can see I am using the MP orange box and the Acell super coil. I also agree that Mopar always says to use the ballast. I just wanted to test it myself since I know a few guys not running a ballast with the MP box so for my own personal mind I want to try it and I carry spare coils and ECU's. But knock on wood the coil does not get hot and its worked fine so far for about 6 months. My farthest run has been about 60 miles so far but its working good and putting out a hotter spark.. I do remember years back MP said do not run the chrome box on the street for more then 30 minutes as it can overheat idling to long and I saw a few guys burn out the crome box on the street with using a ballast of .5 to .75 ohms. As you are right about all the MP electronic ign kits coming with a ballast. The chrome boxes I saw go bad years back were all 5 pin boxes. I just decided to see if my parts hold up with no ballast since some say they will and so far they are right. But ballast or not I would carry a spare coil , ECU and ballast. The ballast is still hooked up in this pic as its from last summer. Ron

 

[383man]

Here is a more recent pic. Ron

 

[furryfrog]

Glad you got it sorted out, good info in this thread for people who have trouble with their stock ignition systems.

 

[moparedtn]

Here is a more recent pic. Ron

Hey, thanks for sharing your info here.
Beautiful, clean ride you have there. Love how clean the plug wire install is.
I want to get rid of my Hedmans on the 440. They make plug changes and wire routing a pain in the arse.

Yeah, I'm thinking from the voltage readings I'm getting at my coil that I could probably run without a ballast, too. I'm nowhere near the 12V rating of the MSD Blaster II.
I did go ahead and order up the 0.8ohm MSD ballast yesterday anyways, just to get a little more juice to the coil than my present 1.2ohm offers. Experiencing a little breakup approaching 5000RPM with the vacuum advance hooked up, so I'm thinking I need a little more firepower.

Curiously, I'm only reading 11V input to the ballast from the ignition switch now. Wonder what's up with that? Battery is new and reads 12.5V sitting, 14.5V when running. Cruddy contacts at the firewall connector maybe? Ignition switch need replaced?

 

[moparedtn]

Glad you got it sorted out, good info in this thread for people who have trouble with their stock ignition systems.

Thanks much.
Yeah, I'm sure all this is old hat for a lot of folks on here, but I'm enjoying learning/sorting it out anyways. Figure if anything else, someone down the road can pick up something to help them, too.

 

[moparedtn]

By the way, what is the difference in the orange box and say, a "standard" ECU on these? Is it just RPM operating limits?

 

[383man]

Thanks for the kind words Moparedtn. As far as I know the rpm limit is the only difference in the MP orange box and stock ones. They say the orange is good to 6000 but my son was shifting his 400 at 6700 with one and no problems and I shift asbout 6200 and trap at 6400 with zero trouble as it never misses a beat. As for your coil voltage if you have about 12.5 at the battery with the key on and eng not running its normal for a small voltage drop through the 14 or 16 gauge wire harness and the ign switch and the bulkhead. If you see 11.5 at the the ballast and 12.5 at the battery thats about the most voltage drop I like to see and as long as the ign works good and the car runs good that should be ok. You can do a voltage drop test by hooking a voltmeter pos lead to the battery pos post and the voltmeter neg lead to the ballast 12 volt side and then turn the key on eng off and read the volts. You want a low reading voltmeter that can read from 0 to 3 volts good as you really dont want to see no more then .5 to 1 volt on the voltmeter when doing that primary ign circuit voltage drop test from the battery to the ballast. I can live with up to 1 volt but like less closer to .5. The higher volts that test reads the more resistance (bad connection) you have between the battery to the ballast. But exspect about a 1/2 (.5 volt) as normal. Ron

 

[moparedtn]

Thanks for the kind words Moparedtn. As far as I know the rpm limit is the only difference in the MP orange box and stock ones. They say the orange is good to 6000 but my son was shifting his 400 at 6700 with one and no problems and I shift asbout 6200 and trap at 6400 with zero trouble as it never misses a beat. As for your coil voltage if you have about 12.5 at the battery with the key on and eng not running its normal for a small voltage drop through the 14 or 16 gauge wire harness and the ign switch and the bulkhead. If you see 11.5 at the the ballast and 12.5 at the battery thats about the most voltage drop I like to see and as long as the ign works good and the car runs good that should be ok. You can do a voltage drop test by hooking a voltmeter pos lead to the battery pos post and the voltmeter neg lead to the ballast 12 volt side and then turn the key on eng off and read the volts. You want a low reading voltmeter that can read from 0 to 3 volts good as you really dont want to see no more then .5 to 1 volt on the voltmeter when doing that primary ign circuit voltage drop test from the battery to the ballast. I can live with up to 1 volt but like less closer to .5. The higher volts that test reads the more resistance (bad connection) you have between the battery to the ballast. But exspect about a 1/2 (.5 volt) as normal. Ron

More useful information. Very kind of you, sir. Thanks!
As all of the wiring (and I assume the switch) is original, there's probably some cruddy contacts somewhere for sure. I'll do a little testing as you prescribe and a little wire tracing to see where any issues lie.

As an aside, I'm also going to remove my heater hoses, as the door inside the HVAC box for cold/hot has come loose from its' pivots and it gets right toasty inside the car, since it doesn't much matter where I set the temperature controls.
This isn't a winter car anyways and I'm not up to removing the HVAC box right now.
I'm assuming the water inlet and outlet nipples @ water pump are standard pipe thread?