CUCV Volt meter hold down placement

[Barrman]

The volt meter on my M1009 has never pointed at the little tick with both alternators putting out 14.4 volts each. It was always in the green though. Lately, it really doesn't even go into the green with everything working.

I have been collecting parts for Colton's RED M1009 for about 2 years now. Once we finally got his truck working great last week electrically, I swapped in a spare volt meter. Now mine reads at the tick like it is supposed to.

However, mine was wired hold down, nut, wires, washer, nut. The replacement gauge and the one in RED were both wired like this: wires, washer, nut, hold down, nut. The -20 shows a different hold down and only 1 set of nuts. Here is all I can find for directions:
"Remove 2 nuts (5) and washers (4), and retaining bracket (1). Remove voltmeter (6) from instrument cluster plate (2)."

Attached is a picture of both options with my old one still in the gauge cover. I don't really need to know the answer, I am just curious.

Thanks.

 

[Keith_J]

There are at least two styles of voltmeters. The plastic hold-down appears to be newer. Mine had the older metal style hold-down. It appears in your picture to have been modified for the plastic hold down. The original meter also use a bracket spot welded to the plate, you can see where it was removed (rust spots in your photo).

 

[CycleJay]

Hi guys,

My voltmeter never reads at the tick either.
Should the wires be under the hold down, or outside of the hold down like in the
upper half of the photo? which way is correct for an accurate voltmetere reading?

 

[cpf240]

Hi guys,

My voltmeter never reads at the tick either.
Should the wires be under the hold down, or outside of the hold down like in the
upper half of the photo? which way is correct for an accurate voltmetere reading?

As long as they aren't shorting out, it should matter. These are not precision instruments, and should only be considered a guideline. The resistor on the back of the meter is not exact, the meter movement isn't exact. If it is in the ballpark, I wouldn't worry about it.

Mine reads just a shade over the line into what would be considered an overcharge condition, but measurements at the alternators and batteries with a good DVM show the charging voltage to be within spec. So, I don't worry about it.

Though I have considered replacing the volt meter with one actually rated for 24v, as I saw another SS'er do. I'd also like to rewire it so that it isn't hot all the time, but that is probably not worth messing with. I'll probably just find some terminal boots to put over the studs.

 

[CycleJay]

Cpf,

Gotcha.. duly noted... Mine usually stays in the green just over the line from the yellow.
But I know the charging system is working well within normal parameters.

So I will not worry about it either...

Night...

 

[stationjj]

Interesting Barrman with your pictures. I noticed ring connectors instead of the plug.

My question should I replace the connector plug with new ring connectors?

I cleaned the connector plug, but I am not sure about it.

Should I replace the plug connector?

Thanks,

stationjj

 

[Barrman]

The plug is at the end of both pigtails. Just out of the picture.

It is kind of funny this came back up. The old volt meter would hover in the lower half of the green. I swapped it out because in the summer when the glow plugs don't work very hard. The needle would stay just above the yellow/green line. Now that it is almost cold out, 48° this morning, the glow plugs glow longer and the alternator actually has to recharge the battery some. My replacement gauge which had been right at the tick in the summer was up against the green/red line this morning coming to work.

I put a volt meter on it at the end of my 5 mile drive without shutting the truck down. I was getting 14.6 out of each alternator. A little bit high, but at least the gauge is actually telling me this. I just haven't mentally adjusted to the new higher reading gauge and was kind of worried about a blown regulator.

 

[Keith_J]

SI regulators rarely fail at full field current which would cause high output voltage. Remember, the regulator not only assures stable voltage regardless of charge state, it also varies field current depending on engine RPM.

Alternators are most efficient at the mid span of their rated RPM range. At low RPM, they won't generate rated current. At higher RPM, they have more waste heat from eddy currents in the magnetic components.