Electrical: Voltage regulator adjustment/replacement?

[fatboylust]

Let me say all I really know about electricity is if you let the smoke out it is broken.

This image shows the ammeter with the engine idling. not the slight positive charge.

This image shows the ammeter with the engine above idle (head lights off). note the heavy charge.

This image shows the ammeter with the engine at idle and the head light on. note the sight discharge.

This image shows the ammeter above idle with the head lights on. note the moderate charge.

Not shown are the changes when the blowers are on, which cause greater discharge at idle and less positive charge above idle.

The question is: Is the voltage regulator performing normally or does is need adjusting/replacing? If adjusting is possible, suggestions on how to do it will be appreciated.

As a side note the fuel tank is full and the gage show 3/4. When the gage is right on the "E" dot the is 4.5gal remaining in the tank. Probably not worth the effort to mess with the sending unit float.

[Bud]

You will need to put a voltmeter on the battery terminals to check the charging voltage which should around 7 volts with the engine running at 1500 rpm or higher. If the voltage is higher or lower than that, you will have to do some diagnostic work to find the cause of the problem. From what I see in the pictures, more likely than not everything is functioning correctly, but it is still a good idea to check the charging voltage. As for the fuel gauge, you can remove the sending unit to inspect the float and adjust if necessary. Before doing that, make sure all of your connections between the sending unit and gauge are good including the fuel tank ground. Bud

[Ross]

Your charging is fine; exactly what I expect to see on a car with a generator; they produce little to no output at an idle. Your gas gauge is probably reading low because the cork float in the tank is getting gas-logged and does not float as high as it used to. The cork float can be replaced with a brass float from a Ford.

[bensherb]

Your charging is fine; exactly what I expect to see on a car with a generator; they produce little to no output at an idle. Your gas gauge is probably reading low because the cork float in the tank is getting gas-logged and does not float as high as it used to. The cork float can be replaced with a brass float from a Ford.

I agree with Ross, it all looks normal to me. FYI; my gas gauge did the same thing and over the course of two years it got lower and lower. It currently doesn't float at all and reads empty all the time, It's just not high priority so I haven't got around to fixing it, but likely will by Christmas.

[fatboylust]

Following Bud's suggestion I checked voltage at the battery and the results are as follows:
At idle (650rpm) with no other load than the running engine the reading was 8.3v.

At idle (650rpm) with headlights on and the running engine the reading was 7.5v.
At idle (650rpm) with headlights, both blowers on high, and the running engine the reading was 6.35v.

At fast idle (2000rpm)

with no other load than the running engine the reading was 9.8v.

Thanks for the replies.

[Bud]

You should see somewhere around 6.9 to 7.3 volts at the battery with a fully charged battery and the engine running above 1500 rpm. The generator will not charge the battery at 650 rpm so a lower voltage reading is to be expected. 9.8 volts at 2,000 rpm with a light load on the electrical system is way too high and the regulator field relay needs to be adjusted or the regulator replaced. Continuing to run the engine with the voltage that high will do damage to the car's electrical components. Did your car have an 8 volt battery installed at one time as that would explain the overly high charging voltage. Bud

[fatboylust]

Bud, it has a 6v battery. I'll watch a few youtube videos on making the adjustment and give it a try before replacing it. Thanks again.

[Bud]

Be very careful when adjusting the spring on the field relay moveable contact as the adjustment is very sensitive. If you have a Delco regulator, there should be an adjusting screw which makes the adjustment easier. If you have an Autolite or an aftermarket regulator, then you will either have to bend the spring mount on the relay or or move the complete moveable contact. Before making any adjustments, let the engine run for a few minutes with the speed above idle to heat everything up. If you don't, the adjustment may not stay the same. Also be sure to check the charging voltage with the regulator cover installed as the cover usually will drop the voltage a bit because it will change the magnetic field around the relays. If you do decide to replace the regulator, be sure to check the charging voltage because about half of them I have seen in recent history are not adjusted correctly. Good luck, Bud

[fatboylust]

Well, still not an electrician, but I played one for a couple of hours. I had a VR on one of my rusty parts cars, which I opened up to get a closer look to determine where to make the adjustment. After reading the 51-54 Shop Manual (Champion) I thought I could just set the "Air gaps" to the values specified and that would be it. It seems the physical limits of the actual adjustment would not permit .048"-.052" cap but there was room in the adjustment increase the initial gap. As the regulator was over charging opening the gap should reduce the charge rate. Using trial and error I was able to achieve 6.1v at 600 RPM and 7.4v at 1500 RPM. Perhaps not ideal but better than the 9+v I had when I stated. Many tanks to all.

[Bud]

7.4 volts is on the high side of the limits, but is still good. I would say that you have made a successful repair. Bud