6 volt generator light question
 

Hello again everyone! I rewired my '54 Ford passenger car last winter, replacing pretty much everything electrical including the generator and generator regulator. Battery, too. I kept the car 6 volt, but the car is negative ground instead of positive (as from the factory.) FYI, the car came to me converted to negative ground, and the people who made the wiring kit strongly recommended keeping that way, as that's how their 6 volt kit is designed. And yes, I DID spark the regulator (per Fordbarn advice) to make sure the rebuilt gen is polarized to negative ground.



Anyway, up until recently, the gen light would go on when I first started the car, then go off in a minute or two (often a lot sooner) as engine speed increased. Sometimes it would momentarily flicker on at low idle or as load was put on the engine when starting out in first gear, but this seems to be in accordance with the shop manual. All normal as I understand it.



Yesterday and today, however, I noticed a different pattern. The light was staying on a long time (15 minutes +) ...and would actually get brighter with engine speed (???) while sometimes being off or close to off at idle. Only when I would get the car up to highway speed (50+) for a short stretch would the light go off abruptly and stay off...at any speed, even idle or starting off in first gear. Any ideas about what might be going on? Haven't got my volt meter with me to check that out, but I will in the next few days.



The only other potentially pertinent info is that I drove the car in the rain for the first time the day before yesterday. It was a pretty light rain though - not enough to even make puddles that splash up into the engine bay. I tried to make the new wiring weather proof, but I may have missed something. Thanks for any input.

Re: 6 volt generator light question
 

I would say to clean the contacts inside the regulator, with the power disconnected.

Re: 6 volt generator light question
 

Get a multimeter or a volt meter and check the voltage. If it's not around 8 volts at fast idle that something has to be repaired - generator or regulator.

Re: 6 volt generator light question
 

Jim, Don't forget, the battery could also be at full charge and not require charging at that time.

Re: 6 volt generator light question
 

Thanks for the input, everyone. Okay, here's what I just did for initial diagnosis (beyond the light staying on):



I hooked up the meter to the battery with the car not running,& disconnected - 6.11 volts.



Meter reading with car cold and running, ( this is when the gen light comes on as engine speed increases, but goes off at normal idle) - right at or just under 6 volts. Voltage does NOT increase or decrease with engine speed.



Took a meter reading again with the car running, but AFTER the car was driven up to hiway speeds (50+ mph) so that the gen light stayed off - 6.78 to 6.8 volts.


I think the voltage should still be higher than this, given that all the components have less that 500 miles on them. I checked the fan belt and I measured the slack at just over 1 inch play in the middle of the belt. I'm told the ideal is 3/4 inch...I don't think that's probably enough to matter, but I'll tighten up the belt when I get a chance.



I'll also clean the contacts as Don suggested, but the regulator is practically brand new...and everything seemed to work fine for the first few months.

Re: 6 volt generator light question
 

Also, just reading the manual; could be this characteristic is a "summertime" thing (?)


Apparently increased ambient temperatures reduce the regulator's voltage range. My readings are actually within the specified range for the higher temperatures...per the shop manual's tables. Ambient temperatures are defined by the manual as temperatures that the regulator has direct contact with. It was 95 degrees F outside when I took the readings. With the engine at operating temp, I'm guessing that part of the engine bay is 130 to 140 degrees maybe. Still doesn't explain why the light is on at lower temps, though. (And why voltage readings are lower.) Another mystery, I guess.

Re: 6 volt generator light question
 

You need to (IMO) to measure AMP output @ the GEN and @ the REG output. The VR is mechanical and is adjustable. VR were calibrated at that time to coincide with the GEN rated output (say 30A, 40A, etc).

The BAT must be @ full charge to run a diagnostics sequence.

The drive belt adj is crucial as too loose will not turn the pulley (belt slippage) @ speed and too tight may cause the GEN rear bearing to burn out.

The GEN disadvantage compared to an ALT is not charging sufficiently @ low speed.

You have a SHOP MANUAL?

Re: 6 volt generator light question
 

Thanks Kultulz. Yes, I have the shop manual, but of course the section for '54 is supplemental, so some of the info I have to get from the '52-3 section. The ambient temp thing was from the '54 section, though.



How do I measure the amp output at the generator and regulator? Thanks.

Re: 6 volt generator light question
 

I wish my scanner was working or I would scan and post the pages.

Re: 6 volt generator light question
 

No problem. I'll look in the manual again to see if I can find something.

Re: 6 volt generator light question
 

Here is a quick tutorial - https://itstillruns.com/test-12volt-...m-7884037.html

Sometimes a SHOP MANUAL can be confusing as it is written for traind and experienced TECHS. Once you understand the basics, the MANUAL will be of more use.

Sorry About That - CRS is a b!tch ... :rolleyes:

Re: 6 volt generator light question
 

Generator lights were usually switched by the generator cut out. When the cut out pole closes the circuit to bring the generator on line, another set of contacts on it opens and turns the light off. At least this is how all the ones I've ever troubleshot worked.

Re: 6 volt generator light question
 

rotorwrench,
The gen. indicator light hooks between the hot post on the ignition switch and the arm. terminal on the generator. When switch is on, and generator not running,voltage goes from battery through light to ground via arm. When generator is running and output voltage equals battery light goes out.

Re: 6 volt generator light question
 

Here, cipher on this - http://www.packardinfo.com/xoops/htm...59EchlinSB.pdf


And this - https://www.chevyhardcore.com/news/t...vintage-chevy/

Re: 6 volt generator light question
 

I've worked on too many 3-brush motorcycle generators. Most all of my old cars don't even have a generator light. Thanks for that Echlin Service Bulletin.

Re: 6 volt generator light question
 

I tightened up the belt from about 1-1/8" slack to 3/4" slack, and - believe it or not - it seemed to help. I wouldn't have thought that small amount would make a difference, but it seems to. Where the car previously needed to be taken out on the highway above 50mph (no overdrive) before the light went off, it now goes off at above 30mph in town. I've been testing it over the last couple of days.



I check the battery voltage right after I shut the car off after driving it enough to turn the gen light off (and then some)...the reading is close to 6.5 volts. After it cools off and sits for awhile, the voltage reading on the battery goes down to 6.2 (+ or -) volts and pretty much stays there. I guess that's workable, but I want to try it at again when the headlights are on.



Maybe someday I'll go to the 6 volt alternator, but they are a bit on the expensive side (if I get the "generator looking" one that will fit my brackets.)

Re: 6 volt generator light question
 

Try replacing the generator belt as it is probably glazed after being that loose.

Re: 6 volt generator light question
 

JimN, glad system is charging. Depending on driving habits and loads the 6V system is ok. I recently got my 47 on the road and was wondering about the 6V charging system in driving conditions. Bought a 0-20V gauge from Summit which showed that the bat is being charged. Made the mount for it out of plastic that I had laying around and just clipped it under dash with a spring clip. Definitely looks out of place in the car though. My friend found similar meters on ebay for around $3


KUL, the Echlin service bulletin has a lot of good info for our old cars - thx for posting that.

Re: 6 volt generator light question
 

Good Point! along with dry rot (I got shots for mine).

Also the pulley(s) could be glazed also.

Re: 6 volt generator light question
 

you are quite welcome.