High running voltage levels on 66 and 67

[AR67GTX]

Yes - electronic gauge regulators in both. As are original radios and a clock (working) in one. I realize the difference in volts and amps but worry about any effects high voltage could have on the battery and primitive circuitry and parts in the car like tach circuit boards, clock points, radio circuits, etc.

So sounds like some of you don‘t feel 14.7 volts is too high?

 

[hunt2elk]

Just after starting the car, 14.7 volts at idle/low rpm would not worry me.

Yeah, but the problem is that 14.7 is the bare minimum that these new electronic regulators run at. Most are 14.8 - 15. And that is all the time, not just after startup. They also do not drop the voltage as temperature increases like the original mechanical ones did.

 

[72RoadrunnerGTX]

Have you verified the reference voltage on ing1 at the regulator is within .5 volts of the battery terminal? Voltage drop between the battery and the regulator is common cause of overvoltage in these charging systems.

 

[AR67GTX]

Not sure what ing1 is? Ignition1? Is this in reference to a test out of the shop manual?

However, on the 66, it has virtually everything new except the rear light harness and console harness. All new forward light harness, engine harness, alternator, voltage regulator, horn relay , starter relay, dash harness, instrument panel and circuit board cleaned/checked, new solid state instruments voltage regulator, clock cleaned/points dressed, radio cleaned up - about the only thing not new or rebuilt/cleaned on the electrical side is the starter.

 

[72RoadrunnerGTX]

Ign1 or Ignition 1 is the run power supply in the engine harness. Dark blue wire at the ballast resistor and voltage regulator “IGN” terminal. Measure the voltage drop, voltage difference between the “IGN” terminal and the battery post while the engine is running.

 

[AR67GTX]

OK, after a cold start and warming up enough to fall off the choke/ fast idle, I measure 14.94 volts at the + battery. And I read 14.56 volts at the IGN side of the regulator. So looks like .38 volts difference. That’s on the 66, can’t get to the 67 immediately.

Ign1 or Ignition 1 is the run power supply in the engine harness. Dark blue wire at the ballast resistor and voltage regulator “IGN” terminal. Measure the voltage drop, voltage difference between the “IGN” terminal and the battery post while the engine is running.
View attachment 1559947

 

[72RoadrunnerGTX]

OK, after a cold start and warming up enough to fall off the choke/ fast idle, I measure 14.94 volts at the + battery. And I read 14.56 volts at the IGN side of the regulator. So looks like .38 volts difference. That’s on the 66, can’t get to the 67 immediately.

If you connect your VOM probes directly as diagramed above, it will show more accurate voltage difference/drop measurement. Looks to be within acceptable range.

 

[AR67GTX]

OK - got started on changing a leaky valve cover gasket but when I’m through with that I’ll try it that way and confirm.

Thanks.

I went ahead and bought a couple of older stock mechanical VRs from Halifaxhops that if all else fails are adjustable.