Voltage, Regulator, Coil, Ballast, MP Electornic Ignition, Standards.

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seabee

seabee

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Hi All. This morning I have been sifting through thread after thread on Ballasts, Coils, Voltages, etc.. I think I have most of my answers but wanted to start a thread for the next guy who comes along and does a title search for Ballasts, Coils, or Regulators. Any advice on what could be wrong or right with my numbers is greatly appreciated.

Here's the stats and readings I got on my car.

1966 Barracuda.
MP Electronic ignition conversion. Orange Box .
VR706 Voltage Regulator
NAPA 45 Amp Alternator
MSD Blaster 2 Coil
.8 ohm ballast resistor
All new Wires and Cleaned Bulkhead connectors.
Ammeter bypassed.

While Running
Battery: 14.7v
At Regulator (Blue Wire) 13.3v
Coil +terminal Voltage: 10.6v (Fluctuates 10.4-10.7)
Coil Temperature: 175'
Ballast Temperature: 146'

With Key in the On position (Not Running)
Voltage between battery+ and Voltage Regulator Blue Wire: 1.3v

What do you think?

-Billy
 
seabee said:
With Key in the On position (Not Running)
Voltage between battery+ and Voltage Regulator Blue Wire: 1.3v
Click to expand...

THIS tells the story. You have a 1.3V drop between the battery and the "run" buss

The path you are measuring here is:

battery -- fuse link -- bulkhead connector -- ammeter circuit -- ignition switch connector -- through the switch -- back out the switch connector (blue run wire) -- back out the bulkhead connector and to the

key side of the ballast

alternator field

regulator IGN terminal

electric choke if used

distributor retard solenoid if used, and maybe some other smog doo dad

What happens here is that the regulator IGN terminal is not only regulator power, it is the SENSING lead for the regulator, so it ADDS that 1.3V dropped reading to it's own (possibly correct) set point

ADDITIONALLY you could have a poor ground at the regulator. To check that, get the car running, bring RPM up to simulate "medium cruise" and stick one probe on the battery NEG, the other probe directly on the regulator mounting flange. Be sure to stab through any chrome, rust, etc. Again you want a low reading the lower the better, and zero is perfect
 
Thanks 73abodee. Del, I'm getting incremental drops through the path. So far:

11.98 Battery
11.94 Starter Relay
11.75 Fuse Link into Bulkhead
11.35 Ammeter Bypass
11.07 Gauge Cluster Lead

On another note: Does the gauge feed get 12v and then the little cylinder with a pigtail to ground drop it 5v? I keep trying to find a voltage limiter for the gauges.

**Disregard the last question. I found my Gas Gauge is the 3 prong type with the limiter built in.
 
I don't know about Barracudas which had the tachometer, but my 65 Dart has the "5V" reg inside the fuel gage. It is an archaic thermal-mechanical switch that modulates on and off, averaging to ~5 V. As most do, I disabled it and installed a $25 electronic Vreg. Search "Plymouth" and "voltage limiter" on ebay, plus posts here. In later cars (my former 69), the Vreg was a separate shiny rectangular box that plugs into the back of the cluster circuit board.
 
Ckeaning wire terminals is a valiant effort and often helps.
Consider this... The portion that can be cleaned might be the size of your pinky nail.
The smaller crimp barrel portion of the terminal that is critical to conduction remains unchanged.
It takes a very long time for moisture to get in and contaminate those smaller spaces. 40+ yrs is a very long time.
Renew requires snip, strip, crimp.
Beyond that, a cleaning flux with the consistancy of water and silver bearing solder, and a silicone moisture barrier ( might be overkill ) is better than renew the OEM.
Yeah I did all of that to my 67 along with a few new larger than OEM awg wires.
I must be krazy.
 
Thanks for the input. I've been tracing through the system and found the biggest drops at the ignition switch and the crimps a PO had made to it's wires. I replaced the Ignition Switch with this Napa Part Number ECH KS6528 . The biggest drop was .72v and that was from the ignition switch to the bulkhead (Blue Wire) that eventually makes it's way to the ballast resister-then the Volt Regulator. I'm replacing all of those old crimps with solder and heat shrink.
 
Don’t forget to check the voltage drop on the ground path. Place black VOM probe on negative battery terminal, and red on chasses of voltage regulator, spark controller if equipped, and alternator case. There should be no drop. If negative path voltage drop is found it can be easily corrected by running a 12 gage ground loop conductor picking up a mounting screw at each device, and back to negative battery terminal.

Also be sure to check negative battery terminal, ground strap to block, and head to fire wall for voltage drop, if any found, clean & remake all those connections.
 
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