I have constantly fought with EMI with my latest rebuild/carb swap.

I am running MSD SuperConductor wires and standard NGK resistor plugs. While I can't use a digital VM in the engine bay due to this EMI I also found out it reaks havoc with my radar detector when I rev the motor.

At idle the radar detector is fine, as soon as I rev the motor it goes off like its being hit head on via radar.



The EMI has not changed through two brands of plugs, and a 'stock' type set of plug wires. I am runnign a ProComp large car HEI dizzy with their '50,000' volt coil.

Can anyone shed some light or help me resolve this issue? It has gotten out of hand...

 

Try magnecore type of wires.

If it’s not enuff suppression you might have to shield the distributor and coil.

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Happy Racing!

 

Any suggestions what could be used to sheild the dizzy and alternator for a quick test?


I have to assume it is either the dizzy (coil) or alternator or something with the wiring. I just don't know what, in all my hacked up wiring, it could be (wiring wise).

 

For this test you will need to install ground braid over each plug wire, then connect the spark plug end of each braid to ground.
You can take it and put it over the plug hex and tywrap it.

Now you’re ready to cover the distributor and coil with aluminum foil, making sure the foil touches all the plug wires, then make sure part of the foil touches ground.
You might be able to fold over the foil to touch the dist base.

You also might have to put an EMI trap in series with the power wire(s) going to the coil.

An EMI trap is basically a coil of wire wound for this purpose and available at electronics parts stores.
You need one that can handle several amps.

If it works then you can install this shielding in a permanent way.

You might want to make some nice looking sheet metal shields for the permanent deal.

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Happy Racing!

 

Thanks for the detail, Nina. Lets hope I make some headway...