I am considering putting new aftermarket gauges volt, oil, temp, fuel in truck that only had temp and fuel originally. Does the cvr have to be hooked to these new gauges and which ones. Original gauges quit working, the small wire inside the gauges burnt in half. Have not checked the cvr yet. Don't know for sure what fried original gauges. Thanks

 

My guess is that CVR shorted and let 12 volts through the guages. You can check the CVR. With the input lead connected to a hot wire, the output should "maintain an average of 5 volts" (shop manual). CVR oscillates when it is good, which seems weird, but that's been my experience (I tossed a good one because it occillated...I figured constant meant constant). I got mine from Autozone for about $20, and it wasn't in stock. New CVR & new guages, gas and temp indicators work well.

I'm not sure about the aftermarket guages, but my guess would be that if the guages take less than 12 volts, you will have to step the voltage down, and if they take more than 5 volts you may need a different CVR. When I bought my '64, it had aftermarket guages mounted to the dash, and, I think, they were wired straight to hot. However, somebody out there has more experience with aftermarket guages than I do.

Has anyone else noticed the occillation in the CVR, or did I inhale too deeply that day? With the shop manual using the term "average" and my guages working, I figured the CVR to be working correctly.

 

Most after market gauge manufaturer instrustions tell you how many volts are needed to make them run. So far I haven't come across any that require less then 12v. If in doubt check out their website. They will have a tech link to help answer that question.

 

I tested the cvr and it did the jumping around most of the time between 0 and 2. Sometimes it went up to 6. Then it would spike up to 14. I guess this spike is what fried my original gauges. Do you remember the part # for your 1964 cvr part from autozone?

 

I don't have the number, but the guys there will lead you through it on their "magic box".

 

Ford Part Number .. B9MZ-10804-C .. CVR

I don't have the NAPA, Auto Zone or Kragen/Checker number, but they do sell the CVR, so I've been told.

 

Just to put a bow on this CVR thing...the shop manual does say that it oscillates between 0 and about 10 volts when working normally...I thought I saw that!

I love that manual, but some things are not grouped in a logical way or indexed logically .

 

Thanks for the info. Us self taught folk really appreciate it.
Do you guys think the spikes up to 14 is what fried little gauge wire?

 

I do...but my question is why it got to 14 volts and not just 12V? I know that home electricity has about 20% excess capacity. Maybe that's it. I'd hate for you to fry more guages and another CVR. Maybe hot wire is jumping to ground under hood?!?!? My original wiring is rough in places.

BTW, my self teaching ended about 2 months ago when I threw away that other CVR!

 

I confirm that the CVR isn't Constant...but averages roughly half the (12V) battery (i.e., ~6V) voltage. It's a bimetallic strip, not unlike what's in the thermal flasher. It was used at least thru '72 (there's one in my Mach 1). If yours shot up to 14V, that's probably what provided the BBQ.

You might also want to check out your primary voltage regulator -- the one that controls what's coming off the Alternator into your main harness.