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maok

'37 Dodge generator/regulator issue

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Hi guys, you may have seen my new '37 Dodge that I recently acquired, which I took delivery mid week.

 

The previous owner installed a kenwood 12v stereo in, you can see its not a perfect match, not the greatest wiring job either but looked okay. A 6v to 12v stepup transformer was also installed because the car is still 6v +ve ground and a noise suppressor module. The missus said, "has to go" which I didn't disagreed with, so I pull it out.

 

Now the ammeter reads full charge (actually, well pass the 20amp reading) as soon as I put my foot on the throttle, even the slightest push. At idle the ammeter needle is at 0. I haven't dug into it yet, but what could make the generator/regulator do this. The only thing I can think of is that the battery is not holding its charge, however, it does turn over and start the car easily, this implies the battery is not bad. Before I removed it, the ammeter was reading correctly. Its got me puzzled for now.

 

Any suggestions?

 

IMAG2909.jpg.1d71289274d5a11ee74d4b082643dfcb.jpgJCM4040710-1.jpg.d5d497e7ab5578e72eff791b4baea185.jpg

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The voltage regulator output might have been modified or adjusted to handle the load placed on it by the step up box.  Without the box the generator is too high.  Check to see what type of regulator you have.  Is it a three brush generator?  They can be adjusted to give more output by moving the third brush setting on the generator.

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Thanks for the reply.

 

At idle, it is charging the battery without any accessories on, I confirmed by attaching a voltmeter on the battery and watched the voltage rise from about 6.4v to 6.9v. At full charge rate, it reads about 7.4v.  When the head lights are switched on at idle, the ammeter reads a discharge, so the ammeter is functioning correctly. Fast idle or anything well above idle the ammeter immediately goes off the scale to +20amp.

 

I have eliminated all the wiring from the  radio, 6v to 12 v step up transformer, there was also a cigarette lighter socket installed under the dash, but with no obvious signs of any issues. It also looked like there was a provision to run the 12 volts accessories from a 12 volt battery under the drivers seat (RHD).

 

I pulled the regulator cover off to find an interesting mod, the cut out relay has been replaced by two diodes in parallel. Either looked more than capable to do the job on its own. So, Im not sure why 2 were installed.

IMAG2921.jpg.a5c5862b958bad83915cd4f5169dfa1c.jpgIMAG2919.jpg.3c24533f05798b4fafc2a10a71252cc7.jpg

 

Both the voltage and amp relays look okay to me, but I have never serviced one. The amp relay ( the centre unit) does not seem to cut out when the engine is revved up.

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So it’s not a three brush generator,  the dual diodes are to ensure they can handle the full output of the generator which is probably about 25 to 30 amps.

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Not only do you have the diode setup but that is a Delco Remy Regulator. Somebody has spent quite some time and money previously trying to fix the charging issue. Since you just bought the car I would start with removing the generator and regulator and having both items bench tested as a set.

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All silicon diodes have a fixed "junction voltage" that must be exceeded for the diode to conduct. No two are exactly the same. A setup like this with two diodes in parallel will result in one diode taking all the load. If that one diode is run over it's limits for current, it will probably fail. Silicon diodes most often fail by shorting. This has the same result as stuck cutout points, except that you can't unstick them and continue driving. I would plan on getting rid of this regulator fairly soon.

 

The pegging ammeter confuses me. One possibility is that the generator and regulator may be capable of more current than the original, and maybe someone added a shunt across the ammeter to increase it's it's current capacity and range, and the shunt has somehow become broken or dislodged.

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Thanks for the replies guys. It looks like this combination of generator/regulator has been added after the restoration, probably due to the extra current needed to run the halogen spot (35 watts) lights, the head lights look like LEDs but I havent checked yet . The user manual indicates that the MC model should have a simple three brush generator with a simple cutout relay, which this setup obviously is not.

IMAG2924.thumb.jpg.ec81bef5443ade9d2427095f5b02a166.jpgIMAG2910.thumb.jpg.2b5d34e0e79a4c113f9f012b86800d1a.jpg

 

This combination obviously worked before I started pulling the radio out, what could I have done to cause this situation, could it be just a coincident...lol  When the restoration was done,  a full rewire has been done very professionally, see the pic of the fuse bank and relays.

 

@Bloo I will check out the ammeter to see if there has been more mods there. Otherwise, it could only be the current relay in the regulator.

@TerryB yes, I agree, but one larger one would have been much easier and efficient.

@certjeff1 the cost of testing and repairing may be more than installing a alternator. I need the charging system to be very reliable and function perfectly due to a non technical person will be driving this car for my business - weddings and tours of my city.

 

Edited by maok (see edit history)

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In the US market, a 1937 Dodge 1/2 ton pickup was a model MC and I owned one.  It had a three brush generator with a simple cut out relay as the regulator.  Cars had the generator and regulator like you show in your pics.  You obviously do not have a pick up.  The generator number on its I’d tag would help identify what it was before any mods might have been made.

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1 hour ago, TerryB said:

In the US market, a 1937 Dodge 1/2 ton pickup was a model MC and I owned one.  It had a three brush generator with a simple cut out relay as the regulator.  Cars had the generator and regulator like you show in your pics.  You obviously do not have a pick up.  The generator number on its I’d tag would help identify what it was before any mods might have been made.

 

It is a MC truck chassis with a tourer body. Here is a link to some pics, 

The pic of the generator plate says - GDZ 4801A genuine Chrysler, but he regulator has  no markings on it, probably some generic delco remy style as @certjeff1 indicate above.

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Well that sure is a combo of parts and pieces!  Never saw a truck quite like that one.   Most of the electrical stuff was Auto-Lite in the US.  Great looking setup!

Edited by TerryB (see edit history)

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Well knowing all that history. That generator was used starting in 1940 and was rated at 35A. The passenger car for 1937 was GBW4803A or C which was 22A. There charge curves are different. With all the added electrical items it makes sense that they went with the later unit. The regulator is Delco Remy most likely from a Chevy with 1118201 part number. Homemade wiring harnesses always gives me cause for concern when trying to troubleshoot in my shop. 

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The current relay point gap measured about 0.023" and the voltage relay point gap measured about 0.025"

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Looks like you may want to add an aftermarket amp gage that can display the higher output of your generator.  The 20 amp gauge is too low for the generator in the car.  You may also want to consider a 6v alternator to simplify the charging wiring.

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Yes, a 6volt alternator is on its way from the land of the free.

 

I have done all the basics, with no luck. Cleaned all the terminals on the generator and regulator, cleaned both the current and voltage  relay points in the regulator. Checked the generator by motoring it ( fan belt not attached). So I am stumped.

 

Next is to get under the dash and look for a short where the radio may have been connected.

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This may have something to do with this issue. Will Inox fix it?   😉

IMAG2930.thumb.jpg.ee43cc01230eb4964b63d1f52a65241b.jpgIMAG2935.thumb.jpg.68a2ca04e328c7e6b1f6cdcf32b08c24.jpg

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Yes it is!  Battery is probably getting so overcharged it’s boiling out the water.  Never tried any battery conditioner.

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45 years in the hobby.........I have never seen battery conditioner! 🤔

 

 

 

Up to 18 percent greater efficiency! More likely 0%..........love fix a car in a can! 👍
 

PS- in this case, it probably can’t hurt anything.

Edited by edinmass (see edit history)

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Add me to the list of having never seen battery conditioner. 

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Really, you never looked in a J C Whitney (Warshawsky) catalog?   VX-6 Battery Additive!😁

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I  have used  it a few times to recover old batteries that have been sitting around for awhile.

This what it does,

IMAG2936.thumb.jpg.f55d288668ae94c0e8c7e781658a7b1a.jpg

 

It worked on this battery but I purchased a new one anyway.

 

The moral of the story is, if you are having charging issues, check your battery first...lol

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On 1/16/2020 at 6:09 AM, maok said:

IMAG2936.thumb.jpg.f55d288668ae94c0e8c7e781658a7b1a.jpg

 


The contents of this box will solve all of your problems, improve gas mileage, reduce oil consumption and increase horsepower ..... all for $9.99 inc tax. Look where it is made! 😀😀😀😀😀😀😀

Rodney 😀😀😀😀

  • Haha 1

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