alexandervdr

I installed the breakerless ignition unit breakerless.com in my original (but new) C2 small block distributor. I now get spark noise in my FM radio, is this normal?

66jack

Did you also change the plug wires to the appropriate resistance?...

69427

A properly designed electronic ignition will turn the coil off a lot quicker, increasing the chances for more high frequency noise in the wiring harness. In addition to the question about what plug wires you have, do you have a capacitor/condenser on the C+ terminal of the coil?

SDVette

The EMI from a spark is the same whether points are involved or not.
It's likely you just have a stronger spark now.

You can use filter caps, shielding, or toroid chokes to try to reduce the noise.

mikem350

Also check/improve all ground connections. Like at antenna mast, radio chassis, antenna connector...etc

alexandervdr

That's probably the culprit. I had bought from ZIP the 'performance' plug wires, which for all I understand are low resistance so bad RFI performance.

Seems the 'standard' carbon core wires are higher resistance ( so weaker spark) but better RFI, and deteriorate sooner.

Anyone knows where to buy plug wires with spiral core for a 327 with standard distributor, supposed to be a good compromise for spark and RFI?

Frankie the Fink

I run the Breakerless-SE and don't have any noise at all with stock radio...
Its prob the plug wires....could be the alternator.....is it constant hissing or a whining increasing with RPM..?

alexandervdr

it's clearly ignition noise going along with rpm. Even putting the shields over the distributor and cables did not help. So I believe it's indeed the spark plug wires, hence my question to have equivalent (with correct length and correct boots) spiral core wires

Yellow6t7

alexandervdr,
You did not say if you have a capacitor/condenser on the C+ terminal of the coil?

alexandervdr

No, Is there one in the original C2?

Yellow6t7

Yes,
See LIC catalog 53-4A

alexandervdr when you get this issue resolved please post how you fixed it. It will be helpful to others.

alexandervdr

Thanks! This may be the missing component, I had not spotted it in the Corvette assembly manual. Are the specs comparable to the many other capacitors that are in the car for noise suppression like on radio and gauges (I have plenty of those, so I could try one of those tomorrow...)?

Earlier today I ordered high resistance spark plug wires, may reduce RFI (put weaken spark too...). It may take weeks before they get here, so I'll love to see the capacitor trick works out tomorrow

alexandervdr

I did put the condensor and unfortunately it does not make too much of a difference. Again, remember I have 'performance' spark plug cables with very low resistance and probably bad RFI shielding. I'll know when I get my 'standard' cables ordered some days ago.

Frankie the Fink

You could try a generic 12V L-C power line filter and that my reduce the noise enough to satisfy you, or maybe not... Hard to say until you try it...they are only a few bucks and you could still leave it in even if you have to go the plug wire route...

alexandervdr

I tried that already, did not work. The point is that I get very clean sound when I (bluetooth) stream music from my iPhone. It's only in the 'radio' position I have the problem which indicates the noise is going through the antenne rather than through the power lines.

Frankie the Fink

I agree...its critical that the antenna ground strap be in good shape and connected properly. It was hanging loose on my '63 and I replaced it -- not a fun job up inside the azz end of a coupe. While at it I replaced ALL of them with the Long Island Corvette ground strap kit

jim lockwood

Better than any other post, this encapsulates what's going on.

There are two phenomena in play:

1. The more rapid rise time of the current when the coil is switched will introduce noise in higher frequencies (such as used by the FM broadcast band).

2. Also, a property of switched inductance, such as that of a coil, is that the Voltage transients are just larger when current through the inductor switches more rapidly.

Likely solution: slow down the rate of change of current through the coil. How? Well, one way would be to get rid of the solid state switching device.

Jim

alexandervdr

If that means going back to breaker points, I am probably not going to try that (please don't turn this into a points versus electronics thread! Both sides are right, but one can only go one side...)

ohiovet

I have had a breakerless Pertronix in my 62 Corvette for 20+ years and have no radio noise with my original AM radio, no FM back then.

Frankie the Fink

I've had a Pertronix in about 8 cars over the years and now run the Breakerless SE system in my '63 and never a hint of noise....