Author Topic: Ignition question  (Read 1574 times)

Offline Dragon383

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Ignition question
« on: May 30, 2014 - 12:30:06 AM »
Hello all,

I got my car started tonight!  Now I am wondering. In my 74 barracuda there is an ignition system/box on the firewall. It has a white two prong resister also.

How can I get rid of it?  Do I have to buy an aftermarket ignition system or is there a simple bypass?  I would like to clean up the firewall a bit. I would like to get rid of the resistor as I have read they have a problem of burning out.

Any insight as to how this box works would be great.

Thanks




Offline Chryco Psycho

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Re: Ignition question
« Reply #1 on: May 30, 2014 - 07:53:52 PM »
The Ballast keeps the coil alive , the coil is only designed to run on 6-7 v long term but with take 13v starting , no real bypass for it but you could hide it elsewhere , just be warned it gets very hot so don't start a fire . The other option is MSD , Crane Hi 6 , there are about 4 types that will fire the coil from the Ecu but the ECU or control box is much bigger & harder to hide than the ballast .

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Offline Bullitt-

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« Last Edit: May 30, 2014 - 08:02:25 PM by Bullitt- »
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Offline polarbear123

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Re: Ignition question
« Reply #3 on: May 31, 2014 - 09:57:13 AM »
A lot of guys put the MSD box under battery.

Offline HP_Cuda

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Re: Ignition question
« Reply #4 on: May 31, 2014 - 02:26:57 PM »

Interesting article when voltage drop could really hurt you with an MSD setup (although this is a racing setup without an alternator it shows the voltage range the MSD setup likes):

http://www.circletrack.com/techarticles/general/ctrp_0711_ignition_system/
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Offline Dragon383

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Re: Ignition question
« Reply #5 on: May 31, 2014 - 10:50:26 PM »
Thanks for the suggestions guys.  It is sad when you are so close to a project that you can't look from a distance and come up with......move the resistor to a different location.  I may look into the HEI thing.  Sounds like a cool simple to hide fix. 

Offline Chryco Psycho

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Re: Ignition question
« Reply #6 on: June 01, 2014 - 06:51:27 AM »
The H|EI never was a very good system , rpm limited , to me adding a GM system to a Mopar is a downgrade but your call

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Offline Strawdawg

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Re: Ignition question
« Reply #7 on: June 01, 2014 - 03:02:25 PM »
I like the HEI a lot because it does not require a ballast and is a lot cheaper than a CD ignition.  If I were to buy a CD type box, it would be a Crane as I had a lot of problems with MSD back in the '90's and old feelings die hard :D

The HEI has a variable dwell in the module which allows you to avoid the ballast.

The module should not be particularly rpm limited as long as you avoid the GM coil that came with them.

Once we were running a Falcon in a vintage class and the Ford ignition would start acting up before we got to 6000 rpm on the front straight away at Texas World Speedway.  We switched to an HEI and matching coil and we starting seeing it flatten out about 6000 rpm.  One of the crew was an EE and he put it on the scope and said the module was not the culprit.  We then tried a Crane PS91 and were at 7200 at the braking point without a falter.  I have seen more comments in recent years blaming it on the coil rather than the module.

Since then, I have tried it on other cars without a problem so when the box on my Challenger started acting up, I swapped to the HEI module and the Crane coil and it has worked like a charm.  Car is a 440 with the Lunati 603 cam so it is not exactly a high rpm engine so I cannot say if it will turn 7000 or not...

The original GM four prong module was current limited to about 5 amps...some of the aftermarket modules like the Accel show a rating of about 7 amps as I recall.

I suspect a lot of the magic boxes out there today have a GM module under the potting compound.  If they use a ballast resistor, it just seems stone age to me.

It is very important to use a good heat sink under the module with a dab of the proper grease under the module for good heat transfer and be sure the module is well grounded and in the air stream if possible.  I guess it happens but I have never seen one fail when installed properly.  I also always hot wire the module straight to the battery with a relay to activate it.  This may be over kill but that's the way we built race cars and I just continue to do it.


Offline Dragon383

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Re: Ignition question
« Reply #8 on: June 01, 2014 - 11:35:25 PM »
Thanks for the info Strawdog. Chryco, I understand peoples resistance to putting other brand parts in there cars. I hate to see a chevy motor in a 30's ford. I look at this more like it is a part to make a car run. If there is a sweet mopar equialent I will buy it, but I would guess it would be posted by now.  For the moment I am going to leave the stock set up because I know it works. It will give me time to think and I will use your idea of moving the ballast so I don't have to look at it. I guess I will just do as I have read and throw a spare in the glove box for now. I am just excited to have it running and want to see all my options before I dead end my new wires.

Thanks again for the info guys.  Also, for Chryco, my friend with his camero loves the idea of adding GM parts :)  He is one of those people... I just see it as some crap made in China that will make a car run. Might have been designed for a Chevy but will work on other things. I mean Carbon Fiber was designed to go into space, does that mean it is an abomanation that it is all over the place now? 
Again, thanks for the input.  I really appricate the help and advice.

Offline Strawdawg

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Re: Ignition question
« Reply #9 on: June 02, 2014 - 09:15:37 AM »
It's okay to put a hemi in just about anything!   :2thumbs:

Offline Chryco Psycho

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Re: Ignition question
« Reply #10 on: June 02, 2014 - 10:40:07 AM »
It is not just a brand thing , the HEI is not really all that good , limited to around 5000 rpm stock & the advance plate moves the wires so they tend to break off

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