The Ford Barn

woodrow · 01-03-2016, 08:35 PM

Our '30 Model A coupe is pretty much stock, 6 volt, positive ground. It has a 6 volt alternator. When I first start the engine the horn won't honk and the ammeter shows a good discharge when I turn on the head lights. After driving 3 to 5 miles the horn honks fine and the ammeter shows normal when the head lights are turned on. What is going on that there seems to be a "warm up time"? Is that normal with the 6 volt alternator or is there something I need to fix? I'm not so good with electrical stuff so a simple answer please.

Thanks

mike657894 · 01-03-2016, 08:42 PM

my horn works well with the car off. look into your connections of your horn wiring.

Y-Blockhead · 01-03-2016, 08:51 PM

Your alternator needs to be 'excited' before it starts charging. Once it starts charging your amp gauge shows normal.

To 'excite' the alternator it needs to be turning at a higher RPM. You are doing this by driving the car. That's the way I do it. You can also try reving the engine when you first start it but I don't like reving a cold engine. Once the alternator is 'excited' it will charge until you shut off your engine again.

But I think you have something else going on with your horn. It should work if the alternator is charging or not. Check your wiring as Mike suggests.

mike657894 · 01-03-2016, 09:13 PM

also you may want to check or add grounding straps. I added a grounding strap because the front right radiator bolt to fender was turning red hot during starting. the engine needs a ground to the frame. and if your horn isnt working but comes on after things have shifted around. your body of your car may need a ground strap. the horn button is supplying ground for the horn circuit.

woodrow · 01-04-2016, 09:00 AM

Thanks for the good answers. A buddy is coming over this week to look at it. I think your answers are pretty much on target. He's an aircraft mechanic and does electrical stuff. I'll let you know what he finds out. Thanks again

Herb Concord Ca · 01-04-2016, 01:21 PM

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If you have a starter mounted fuse, you should remove it when you are done driving for the day. Some of the alternators have an internal current leakage and will discharge you battery over a number of days.
Just remember to re-install the fuse before you start up the A.

Willie Krash · 01-04-2016, 03:40 PM

Y-Blockhead is quite correct, normal situation.
Once it turns on it will set a loop to the VR.
It will vary in turn on speed btw..This too is normal. Pulley size plays into as well.

Gary WA · 01-04-2016, 03:46 PM

Horn may cleaning contacts/brushes. plus a very light oiling

Bruce Adams · 01-04-2016, 06:25 PM

Definitely the alternator must be "Excited" at each start for it to produce juice. Some say you might wish to hook up an "Idiot Light" which would eliminate the need to rev it up, but its easier to rev than to screw with an accessory in my opinion.

MrBruce · 01-06-2016, 05:04 PM

Woodrow, you can buy a smaller pulley from most of the Model A suppliers which will turn the Alt faster and excite it quicker. I always just give it a little throttle when it starts and it excites write away. I think most of the newer sold units have a quicker exciter in them.

BILL WILLIAMSON · 01-06-2016, 09:42 PM

Quote:

Originally Posted by Gary WA

Horn may cleaning contacts/brushes. plus a very light oiling

Yes, do as Gary said,
Lots of folks don't know about oiling the felts on the motor shaft, under the horn cover. Manuals say to oil them every 3 MONTHS
Bill W.

Al 29Tudor · 01-07-2016, 05:29 AM

Quote:

Originally Posted by Bruce Adams

Definitely the alternator must be "Excited" at each start for it to produce juice. Some say you might wish to hook up an "Idiot Light" which would eliminate the need to rev it up, but its easier to rev than to screw with an accessory in my opinion.

Bruce please tell me more about adding an idiot light. How is wired in?
Thank you.
Al

rscardina · 01-07-2016, 08:55 AM

Quote:

Originally Posted by Herb Concord Ca

If you have a starter mounted fuse, you should remove it when you are done driving for the day. Some of the alternators have an internal current leakage and will discharge you battery over a number of days.
Just remember to re-install the fuse before you start up the A.

Or install a battery disconnect switch.

TerryH · 01-07-2016, 12:30 PM

I agree with the comment on an alternator mounted fuse, but you do not need to remove it, but just pry up one end of the fuse so it is not making contact. Tom Endy takes old clothespins apart, and uses the small wooden angled piece as a lever to pry it up.....works perfect and is very quick and easy to do.

Y-Blockhead · 01-07-2016, 01:13 PM

Quote:

Originally Posted by Al 29Tudor

Bruce please tell me more about adding an idiot light. How is wired in?
Thank you.
Al

Yes please do explain how you connect a idiot light on an One Wire alternator.

As far as I know you can only connect an "idiot" light (I prefer the term "indicator" light on a Three Wire alternator.

jax55 · 01-07-2016, 06:55 PM

Although it is a "one wire" unit, that only means only one wire is needed for the unit to work. The "L" (light) terminal can still be used and creates a resistance through the light to cause the regulator to excite more quickly.
I have a one wire alternator on my Chevy, and it excites immediately when I start it.
I do not have one on my "A", but know from experience this works on one wire alternators. I have suggested to people confronted with this problem to do this and just leave the light under the hood, rather than try to run it inside the car.
Now, or course this would not be applicable for a points car, but with an alternator... it's not a points car anyway.
Give it a try with a test light before you start attaching things, just so you are satisfied with the results.

AL in NY · 01-07-2016, 07:40 PM

jax55: I'm sorry. but you can have an 6 volt alternator on your Model A and still pass fine points judging. Russ Evans makes a 6V/45amp unit and it's inside a Model A generator housing. Looking at it you can not tell it isn't an original Model A generator.

jax55 · 01-07-2016, 11:48 PM

Al, you are correct and I apologize for the error. I was picturing the aftermarket alternator when I made the comment.
Now, am I incorrect in assuming there is no light terminal on the Russ Evans unit?
I have never seen one, so am curious.

Thanks for reminding me of the other version of the alternator.

Mike V. Florida · 01-08-2016, 12:38 AM

Depends on the alternator. There are alternators for 12 volts like this one http://www.summitracing.com/parts/tff-7127 that can be used as a one wire or three.

I admit I don't know about the 6v alt's sold by the vendors.

jrelliott · 01-08-2016, 11:19 AM

Woodrow send me an email to [email protected], and can send you the information on how to convert the one wire alternator to a 3 wire and will eliminate the problem of having to rev up the engine to get the alternator to charge. You will have to remove the fuse as others have mentioned as it has a small draw on the battery to energize the alternator even when sitting.

01-03-2016, 08:35 PM	#1
woodrow Senior Member Join Date: Apr 2012 Posts: 141	6 volt alternator question Our '30 Model A coupe is pretty much stock, 6 volt, positive ground. It has a 6 volt alternator. When I first start the engine the horn won't honk and the ammeter shows a good discharge when I turn on the head lights. After driving 3 to 5 miles the horn honks fine and the ammeter shows normal when the head lights are turned on. What is going on that there seems to be a "warm up time"? Is that normal with the 6 volt alternator or is there something I need to fix? I'm not so good with electrical stuff so a simple answer please. Thanks

01-03-2016, 08:42 PM	#2
mike657894 Senior Member Join Date: Oct 2015 Location: Bay City Michigan Posts: 1,050	Re: 6 volt alternator question my horn works well with the car off. look into your connections of your horn wiring.

01-03-2016, 08:51 PM	#3
Y-Blockhead Senior Member Join Date: Jul 2011 Location: Redondo Beach, CA Posts: 6,647	Re: 6 volt alternator question Your alternator needs to be 'excited' before it starts charging. Once it starts charging your amp gauge shows normal. To 'excite' the alternator it needs to be turning at a higher RPM. You are doing this by driving the car. That's the way I do it. You can also try reving the engine when you first start it but I don't like reving a cold engine. Once the alternator is 'excited' it will charge until you shut off your engine again. But I think you have something else going on with your horn. It should work if the alternator is charging or not. Check your wiring as Mike suggests. Last edited by Y-Blockhead; 01-03-2016 at 09:04 PM.

01-03-2016, 09:13 PM	#4
mike657894 Senior Member Join Date: Oct 2015 Location: Bay City Michigan Posts: 1,050	Re: 6 volt alternator question also you may want to check or add grounding straps. I added a grounding strap because the front right radiator bolt to fender was turning red hot during starting. the engine needs a ground to the frame. and if your horn isnt working but comes on after things have shifted around. your body of your car may need a ground strap. the horn button is supplying ground for the horn circuit.

01-04-2016, 09:00 AM	#5
woodrow Senior Member Join Date: Apr 2012 Posts: 141	Re: 6 volt alternator question Thanks for the good answers. A buddy is coming over this week to look at it. I think your answers are pretty much on target. He's an aircraft mechanic and does electrical stuff. I'll let you know what he finds out. Thanks again

01-04-2016, 01:21 PM	#6
Herb Concord Ca Senior Member Join Date: May 2010 Location: Concord CA Posts: 755	Re: 6 volt alternator question Sponsored Links (Register now to hide all advertisements) If you have a starter mounted fuse, you should remove it when you are done driving for the day. Some of the alternators have an internal current leakage and will discharge you battery over a number of days. Just remember to re-install the fuse before you start up the A.

01-04-2016, 03:40 PM	#7
Willie Krash Senior Member Join Date: Jan 2012 Location: Phoenix, Oregon Posts: 661	Re: 6 volt alternator question Y-Blockhead is quite correct, normal situation. Once it turns on it will set a loop to the VR. It will vary in turn on speed btw..This too is normal. Pulley size plays into as well. __________________ Mike Stitt "A business that make nothing but money is a poor business." -Henry Ford

01-04-2016, 03:46 PM	#8
Gary WA Senior Member Join Date: May 2010 Location: Clinton,WA/Whidbey Island Posts: 4,457	Re: 6 volt alternator question Horn may cleaning contacts/brushes. plus a very light oiling __________________ www.whidbeymodelaclub.com

01-04-2016, 06:25 PM	#9
Bruce Adams Senior Member Join Date: May 2010 Location: Northport, NY Posts: 1,597	Re: 6 volt alternator question Definitely the alternator must be "Excited" at each start for it to produce juice. Some say you might wish to hook up an "Idiot Light" which would eliminate the need to rev it up, but its easier to rev than to screw with an accessory in my opinion.

01-06-2016, 05:04 PM	#10
MrBruce Senior Member Join Date: Oct 2014 Location: Charlotte, NC Posts: 327	Re: 6 volt alternator question Woodrow, you can buy a smaller pulley from most of the Model A suppliers which will turn the Alt faster and excite it quicker. I always just give it a little throttle when it starts and it excites write away. I think most of the newer sold units have a quicker exciter in them.

01-07-2016, 12:30 PM	#14
TerryH Senior Member Join Date: May 2010 Location: Fountain Valley, Calif. Posts: 937	Re: 6 volt alternator question I agree with the comment on an alternator mounted fuse, but you do not need to remove it, but just pry up one end of the fuse so it is not making contact. Tom Endy takes old clothespins apart, and uses the small wooden angled piece as a lever to pry it up.....works perfect and is very quick and easy to do.

01-07-2016, 06:55 PM	#16
jax55 Senior Member Join Date: May 2014 Location: Santa Barbara, Ca Posts: 329	Re: 6 volt alternator question Although it is a "one wire" unit, that only means only one wire is needed for the unit to work. The "L" (light) terminal can still be used and creates a resistance through the light to cause the regulator to excite more quickly. I have a one wire alternator on my Chevy, and it excites immediately when I start it. I do not have one on my "A", but know from experience this works on one wire alternators. I have suggested to people confronted with this problem to do this and just leave the light under the hood, rather than try to run it inside the car. Now, or course this would not be applicable for a points car, but with an alternator... it's not a points car anyway. Give it a try with a test light before you start attaching things, just so you are satisfied with the results.

01-07-2016, 07:40 PM	#17
AL in NY Senior Member Join Date: May 2010 Location: Southern Upstate New York Posts: 1,209	Re: 6 volt alternator question jax55: I'm sorry. but you can have an 6 volt alternator on your Model A and still pass fine points judging. Russ Evans makes a 6V/45amp unit and it's inside a Model A generator housing. Looking at it you can not tell it isn't an original Model A generator. __________________ AL in NY

01-07-2016, 11:48 PM	#18
jax55 Senior Member Join Date: May 2014 Location: Santa Barbara, Ca Posts: 329	Re: 6 volt alternator question Al, you are correct and I apologize for the error. I was picturing the aftermarket alternator when I made the comment. Now, am I incorrect in assuming there is no light terminal on the Russ Evans unit? I have never seen one, so am curious. Thanks for reminding me of the other version of the alternator.

01-08-2016, 12:38 AM	#19
Mike V. Florida Senior Member Join Date: May 2010 Location: Florida between Sarasota and TampaSouth Florida Posts: 14,054	Re: 6 volt alternator question Depends on the alternator. There are alternators for 12 volts like this one http://www.summitracing.com/parts/tff-7127 that can be used as a one wire or three. I admit I don't know about the 6v alt's sold by the vendors. __________________ What's right about America is that although we have a mess of problems, we have great capacity - intellect and resources - to do some thing about them. - Henry Ford II

01-08-2016, 11:19 AM	#20
jrelliott Senior Member Join Date: May 2010 Location: Pine, AZ Posts: 823	Re: 6 volt alternator question Woodrow send me an email to [email protected], and can send you the information on how to convert the one wire alternator to a 3 wire and will eliminate the problem of having to rev up the engine to get the alternator to charge. You will have to remove the fuse as others have mentioned as it has a small draw on the battery to energize the alternator even when sitting.