Converted to hei and now i have rf interference

[Jakethesnake73]

Installed an hei dizzy into my 73 pickup and now my speakers cut in and out. Ive made sure all wires are in good shape.  I found that the positve wire that i ran from the fuse block would make the speakers cut out qhen juat the outside got close to the speaker wires. To solve that i ran a relay so now i just have a signal wire inside the cab.  However that didnt solve my problem as the speakers still cut out. Any thoughts? Maybe an alternator from a 75 or newer that would have had electronic ignition already?
I should also include that i have a retrosound stereo with the external usb ports.

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[bd]

Cut in and out, as in turn on and off, or buzz with changing RPM?

[Jakethesnake73]

No buzzing. The stereo will stay on but the speakers turn off and on

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[bd]

Sounds like an interruption of power or ground to the radio.  Recheck your installation.

[Jakethesnake73]

I have already rechecked it. It works just fine when the engine is off which is why i believe it to be rf interference from the hei

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[bd]

I'm skeptical about RFI causing the symptoms you're describing and more inclined to suggest a noisy power bus or severe voltage loss.  Describe where you connected the distributor to ignition power.  What gauge wire did you use?  Did you rely on the original primary wiring or install an all new power lead?  As a test try running a dedicated 10-gauge wire from battery directly to the distributor B+ terminal and see if the symptoms go away.

[Jakethesnake73]

I used 10 gauge plugged into the fuse block labeled ignition. When  i did the relay i used the same 10 gauge and a 12 gauge yo make it longer. I will try the 10 gauge directly to the battery tommorow

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[Jakethesnake73]

It was recomendedto me to put a ferite core on the power wire up close to the radio. I put it around the constant and ignition wire. Fired the truck up and no luck. I also added one that went around both the power anteena wire and remote/amp turn on lead. I went for a quick drive and no issues. I also have some around the usb and aux output wires but dont know if they are helping. I will be back soon with an udate after driving a day or two.
Btw this is a retrosound model two stereo if i havent mentioned it yet

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[Dr_Snooz]

Forgive me for knowing nothing about this, but is there not a capacitor meant to soak up rf interference?

[Jakethesnake73]

I believe so. I think it was attached to my old coil however the hei being a different set up i couldnt use it. I am not sure of this

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[bd]

If noise is being introduced by the HEI through the primary wiring, a high value capacitor, such as an MSD 8830, installed as close to the distributor as feasible in the B+ lead may do wonders to filter it out.  The fact that installing a ferrite sleeve around the amp turn-on lead has an effect suggests that the amp is resetting and killing the speakers in the interim.  Take a close look at that circuit, the lead and its connections.  Although an oscilloscope is the optimum tool, if you have a voltmeter, monitor the amp turn-on voltage emanating from the head unit.

Did you ever try the battery to HEI jumper as a test?

[Jakethesnake73]

I think im understanding you correctly I dont have an external amp just a wire lead coming from the stereos wiring harness. I will test the lead i have for voltage. I hope to test directly to the battery this weekend for your curiousity and mine. Id like to add the msd filter but if this ferite core seems to work after i drive tommorow i will probably avoid the 40$ for the filter

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[Jakethesnake73]

Radio worked on the way to school but didnt work on the way back. Going to order the msd capacitor and try the 10 gauge wire directly to the battery while i wait for that. Still need to test the amp lead. I redid all my power wires and the connections for the speaker wires as it was a mess down below the dash.

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[bd]

I wouldn't order that MSD capacitor just yet.  At least, not before monitoring B+ voltage and ground into the radio.  Electrical noise introduced by the ignition system, whether broadcast or injected directly through the wiring, generally results in a "buzzzzzzz" through the speakers that varies in frequency with engine RPM.  I still think you are facing a more fundamental issue with power or ground or compromised wiring.  Think about this: the symptoms temporarily disappeared after adding the ferrite chokes.  Do you suppose you may have disturbed and temporarily restored a poor connection in the process?  How about the possibility of a wire broken inside of its insulation jacket or where the wire crimps to its terminal... or even a damaged terminal?  If you abandoned the original primary ignition wiring in the vehicle when you added the HEI, is there any possibility it is arcing to ground?  Not trying to stall your progress, just prevent a $45 investment in a solution that really isn't.  Keep us posted.

[Jakethesnake73]

I was thinking about i might of disturbed a wire but i cant seem to pinpoint any. The last wires to replace would be the speaker wires and they are a pain to route. I might take some new speaker wires and some old speakers and just set them on the floor to see where that gets me. The old positive wire from the points system is now wire to the electric choke.

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