I am still having problems with the battery guage in my 66. When I turn the key on the guage will drop slightly and when I start it the guage acts like a tach going up & down with the rpms. I have checked all the grounds and they look fine ( bird cage to frame,engine to frame,exhaust to frame,pwr ant to frame,throttle to manifold alt to voltage reg.,wireing harness to guage cluster and radio harness to z bar. I just compleated changing all wireing harnesses in the car and everything else works fine.The only thing different from before changing the harnesses is the car did not have a balast resister between the ign. & Dist and I installed the correct one with the harnesses. ( the dist. does not have a tag on it but it appeares exactly like the one in my 65 ). I have also tried installing a new Wells VR-715 voltage reg. and nothing changed. Any suggestions to correct this Problem? I don't want to try driving it or letting it run without knowing what is wrong.
Thanks
Jeff

 

When you say it goes up and down like the tach, from where to where does it go? It should not go below 0 (zero). It should be to the right of 0, and it will move farther to the right as you rev the engine because the alternator output increases with speed. As you let the engine run, it should eventually stabilize at or a little to the right of 0. How long that takes depends on how well your battery was charged to start with. If the car has been sitting for awhile, it may take a drive of several miles before it zeroes out.

 

When I haven't run mine in awhile, at the start it does look like a tach with the revs but after running for a while settles down to a steady to the right of 0 charge.

 

I'll try running it tomarrow and see what happens
I do know that it goes a little below zero with the key on and not running but I dont think it goes below zero when running. I'll let you know tomarrow.
Thanks for the help.

 

Sometimes while running it still will go below zero for a second or two like when you first put on the headlights for instance which is normal.
Don

 

I found the problem. While I was changing the harnesses I decided to remove the altenator brackets to repaint them and I put the alternator on the shelf next to another one that was 63 amps.I grabbed the wrong one off the shelf like a fool without checking it. I installed the correct one last night and everything works fine now.
Now the only problem is the loud noise created by my two daughters ( ages 10 & 13) arguing about who's turn it is to go for a ride.Its music to my ears though because I know all too soon they will be to "busy" to go with me and I would give anything to hear the "loud noise again"
Thanks for the suggestions.
Jeff

 

IMO both alternators should produce the same results. If the alt on your car is less than 63amps and can't charge the battery, it may have a problem. I use a 135amp on mine to carry the aftermarket load.

The 63amp alts are generally found on c2s with A-C but will work fine in place of the nonA-C alts and have an easier time charging at idle speeds too.