This question is sort of directed at Pete (AKA FordBoyPete) as he alluded to it in another thread and rather than hijack the other thread, I started a new one. All answerers are appreciated though!!

I have what I believe to be a stock alternator setup from a 1965. Probly has the adjustable regulator as well (mechanical). Has an unused wire comming off the wiring harness by the regulator, as well as by the alternator. My manual shows capacitors in those locations to reduce radio noice.

I have, as FBP would put it, a "high dollar" radio (in my case, a completely stock looking rebuild that has AM/FM stereo guts in a stock case). Sounds swell with the engine off, but thereafter, I get whine which varies with engine speed, indicating alternator or ignition noise.

Anyone know what capacitor to use?

Anyone know, can I put a choke coil of some sort in the "+" line coming into the radio that might help? I recall putting something like that in my 1979 Mustang, but I cannot seem to find such a beast in 2004.

Thanks

David

 

Dave,
you're right on! The whine that rises with engine RPM is a spurious charging system generation, or more likely "leak". I believe it was 2500mfd capacitor at both locations on the charging systems.

Upgrade to electronic V' Reg too. It's solid state & pretty bullet proof as long as it's a decent brand. Wells "Zucks" so do several others, but Echlin, Motorcraft, and a couple other "Brand Names" are fine. they make every alternator perform better. Also they do not "go away" like the internal regulators do. The internal regs get killed by heat they are exposed to. Mechanical V Regs wear out like points used to do from motion and from arcing due to their function of opening & closing so many times. mount your new solid state electronic V Reg where it'll be coolest since you have to mount it anyway.

Also run service lead to radio off batt'ry Positive terminal as dedicated solitary wire, rather than pick it up in under-dash harness or fuseblock. Also dedicated ground to negative batt'ry terminal helps too. You can get Batt Cables with an extra wire of small gauge (#10-#12 ga) at terminal clamp. No it's not OEM stock, but the tunes sure do work great.

If you don't want to have to switch radio on & off every time, get a relay, like a fuel pressure relay off an EFI to actuate & de-actuate radio service lead with Ignition switch on/ off. Also dedicated engine/block to body ground straps and ground your hood with a ground strap to body at the cowl too.

Ya gotta remember Dave, there were no FM Multiplex Auto Radios in mid 60s. It was 8 tracks and re-verbs. FM band width sensitivity collects corona/ spurious background emissions,andmagnetic fields AM radios don't even recognize. So any electric component capable of generating spurious fields, coronas, or magnetic resonance field are picked up by a good FM receiver. Even fields within harnesses & under dash, like a gauge CVR, in mid 60s vehicles were leaky. No supression or shielding was used at all then because they did not recognize the need or the cure, doncha see? Anyway, you can get capacitors at Radio Shacks that sell parts as well as Cell phones and doo dads.
FBp

 

Thanks Pete. Will try radio shack for 2500 mfd capacitors. I hate to run the dedicated lines quite yet, as I am trying to keep the jumble under the hood to a mimimum and retain the stock look. Will see. Will try the electronic regulator as well.

later......

 

When I worked for Ford we had a TSB pertaining to alternator noise in aftermarket high-end radios. It called for wiring in a relay to power radios and amplifiers. Just something to consider.

 

Instig8r63,

That's what I was ref'ng to in paragraph 4 when I ref'd using constant "On" relay like a Fuel PSI relay from EFI, to make remote wiring work as a key operated on/ off deal. I think whole point of that TSB is isolation of receiver/ amp from main system circuitry.
FWIW, our older trux seem to get better tunes with dedicated power supply leads.

One major problem we have with our Slicks is the circuitry isn't even right for printed circuits and boards. Like the dash instrument printed circuit of say a 73 - 79 or the boards in a Dura Spark Main Module. Our systems lack sophisticated ground looping req'd for more current sensative set ups.

I spent time looping grounds and linking body-frame-running gear components into a common looped ground. Then I isolated speakers & tuner/player grounds into 1 looped, common, "tunes" ground. Probably didn't need to do all that but I hate hearing my charging sysem or ignition system in my tunes.

FBp