Radio noise (1 Viewer)

[fcgadget]

I replaced a bad coil and now have radio noise. Nothing but the coil was changed.
The noise is louder with more RPMs.
Any suggestions?


Internal ballast
Fireball XR700 ignition

 

[1911]

Make sure the coil and alternator are well grounded. I had to put a ground strap from my exhaust pipe to the frame to get rid of some similar noise in my cb radio. There are also capacitors you can put on your alternator that will help - don't know that you want to put one of those on your coil though.

What coil did you buy?

 

[Engineer8000]

@ToyotaMatt

 

[bhsdriller]

Yep usually a ground issue with radio noise even on modern cars

 

[fcgadget]

I get that I might need the capacitor, and that one side goes to ground...but where does the other side connect in the Fireball system?

 

[bhsdriller]

What coil? Where do you have the shown ground on the diagram installed?

 

[Engineer8000]

One side to coil, other side to ground.

 

[73FJ40]

One side to coil, other side to ground.

+ coil terminal or - terminal, or does it matter?

If - terminal, does it matter if the dizzy is old school points/condenser (therefore 2 condensers on negative terminal wire) or if its ignitor style or Pertronix?

 

[fcgadget]

my replacement coil is a NAPA Eichlin

there's no separate ground from the coil- ....there is a ground from the Fireball box, don't know if that's a straight from ground or through some circuitry...I'll have to throw a meter on it...

 

[Engineer8000]

FSM shows it on the + side. You typically install it on the + side of the coil for RFI suppression. The one on the negative side (on the distributor) would be to protect the points contacts.

factory:

 

[ToyotaMatt]

I replaced a bad coil and now have radio noise. Nothing but the coil was changed.
The noise is louder with more RPMs.
Any suggestions?


Internal ballast
Fireball XR700 ignition

Make sure the coil and alternator are well grounded. I had to put a ground strap from my exhaust pipe to the frame to get rid of some similar noise in my cb radio. There are also capacitors you can put on your alternator that will help - don't know that you want to put one of those on your coil though.

What coil did you buy?

FSM shows it on the + side. You typically install it on the + side of the coil for RFI suppression. The one on the negative side (on the distributor) would be to protect the points contacts.

View attachment 2907953


factory:

View attachment 2907949

i have the 2 pc kit :

VintageTEqParts.com

vintageteqparts.com

 

[fcgadget]

as usual, my setup looks nothing like most of what is posted. Connections/jacks are not in mine, components are different. Sometimes makes me wonder just how many variations on a theme there can be.

The capacitor from coil + to ground seems like the best idea. I will try it and see

Thanks all!

 

[fcgadget]

should have asked .....is there a standard noise suppressor capacitor?

 

[Engineer8000]

They are usually specified .5 mfd (really 0.47uf) 200-300V. The one Matt sells fits the bill.

 

[fcgadget]

I went looking for a RF noise suppression capacitor, after hitting numerous "parts" stores and getting the same confused look from every one of them, I found a store that not only knew what they are, but actually had one in stock! I didn't care what the specs were. They did have it listed under condensor, not capacitor.

Put it on the coil+ to ground and everything works just like it should.

 

[Engineer8000]

Small engine shops will have them usually, you can find a kohler or onan PN for the value you are looking for.