breakerless ignition and radio noise
 

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?

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

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?

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.

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

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?

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..?

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:thumbs:

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

No, Is there one in the original C2?

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.

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:thumbs:

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.

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...

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.:thumbs:

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:thumbs:

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

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...):hide:

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.

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....

The capacitor on the C+ terminal is there to reduce/prevent noise being induced into the vehicle harness and into the radio power supply. Once you have the cap in place then you need to address the plug wire issue. Low resistance/reactance plug wires allow a high current spike to occur once the plug arcs over. This high current pulse radiates everywhere, both into the wiring harness and into the antenna. If you can slow down/reduce the plug current spike it should help reduce the noise in the radio. Let us know how things are when you change the plug wires.

I am surprised nobody asked if you were running a stock or aftermarket (newer) radio, some of which require additional wiring and grounds. :confused2:

The aftermarket radios I have run have a big bolt that goes into the PS side mount point and thoroughly ground the case....the AAR repro for instance; I guess there are others that might float in the mounting and require a separate ground... Its also possible the radio has a defect as the Bluetooth works whereas broadcast stations do not (without noise)...

This last factor is a key clue - it may preclude noise introduced into the power line...

That's not quite a fair comparison. Bluetooth thingys operate in the 2.4GHz range while FM broadcast is waaaaay down there at 0.1 GHz. It's unlikely that any noise source, such as ignition, could generate any noise energy up at 2.4GHz.

Jim

That is true.

Its easy enough to tell....if the radio has an AUX or pin jack just play some tunes through that for a bit and see if the whine is there:thumbs:

Frankly, I could have changed the plug wires in the time its taken to produce this thread...:D

To the OP: I wouldn't worry two nits about resistance plug wires creating "weak" spark....its a non-issue for about 98% of our cars running the streets...

And I just thought about something else which would make Bluetooth thingys immune to ignition noise...... in all probability they communicate digitally which is about as noise-immune as you can get.

AM and FM broadcast both use analog technology, which is inherently more susceptible to radiated noise.

Jim

All these little things.....lets see the car....some video of it moving.....I think it is all made up.......lol......Ingrid , take some pictures while he is out.......

Jack

all the comments make sense, I am now waiting for the higher resistance spark plug cables to cross the ocean (and the customs...)
That may take days or weeks, depending on the temper and mood of the 'red tape' .:willy:

As soon as I have tested them , I will let you know my findings:thumbs:

by the way: did I tell already that I installed the distributor top ignition shield , did not make any difference.

Still trying to figure out how the OP is having noise trouble with FM (he didn't say whether AM was affected). FM is essentially immune to most electrical noise from sources in the car like plug firing and power switching. All those noise suppression capacitors are for AM, which will pick up any amplitude-change electrical noise that has frequency components in the bandwidth of the 455 KHz intermediate frequency amplifier. Unshielded graphite core plug wires usually don't have any effect on FM. A strong AM broadcast signal will usually override noise from unshielded graphite core plug wires.

The OP also didn't mention what kind of "high performance" plug wires he got from Zip. All I could find in their on line catalog were Pertronix wires, which are good ones for noise suppression - graphite center core with spiral wound resistance (nickel chrome or monel) wire covering the graphite. These wires generate less radio noise than uncovered graphite core wires because of the spiral wind of the resistance wire. The field generated by spiral core wires runs along the length of the wire, rather than perpendicular to the length of the wire (the same for graphite core or copper solid core wires).

Something else is going on beside the plug wires and breakerless ignition.

what I got was "57-74 Performance Spark Plug Wire Set" from ZIP
Item #: M-3962

Alexander, I just checked the wire set you mentioned. They're 250 ohms/foot. I'm running Bosch spiral core wires (50 ohms/foot stuffed in correct BBC braided wire shields). I'm also running a mallory unilite module as a trigger and an old MSD 6A analog box to jolt the coil. NO noise on FM or AM. You've got a radio problem. Your ignition mods just don't create enough RFI to put noise in a properly working original Delco radio with factory ignition shielding. Especially on FM.

Thanks for this detailed info. The braided part of your set-up may have an impact? Note that I have a modern Pioneer in there. Thats' the one that 's having the noise problem.
Where did you get the 250 ohms/foot info of the wires I bought? It's not on the ZIP site.

Maybe the alternator/regulator is inducing some noise. Could pull the belt and test real quick.

it's on their mobile site at

http://www.zip-corvette.com/57-74-performance-spark-plug-wire-set.html

I tried it all, nothing worked (including going to the high ohm spark plug leads).
The final check was the antenna itself that had a problem. I installed a new one and that was way better, waiting for better weather to fully check and report cause rain is pouring like hell, and will do so for the next couple of days.:ack:
In case you are wondering: I installed an 'indoor' antenna, although I had tested it something went wrong:hide:

I've been looking for one of thoes indoor antennas. Where did you get it?

there is plenty on eBay type 'indoor car antenna':thumbs:

some update. Even the replacement indoor antenna did not work out well, was better still very noisy. So I Installed a (retracting) antenna in the rear (means taking off exhaust...) and that did it. Difference in reception quality is hughe. There is still some light ignition noise especially when station signal gets weaker, but only audible when at idle. Above that , car noise takes over :thumbs: