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alternator issue
Posted by: corvairbob ()
Date: May 15, 2019 06:48PM

i have had issues with my alternator since i got this car. when the car idles the voltage goes down so far it almost shuts of the engine. i had a pertronix in it and the voltage got so low it burned out the pertronix 3 times before i figured it out that the low voltage was the issue there.



i put in a one wire unit stock amp and that did not work



i changed the pulley so the alt would spin out faster and that did not work



i then changes the guts to 80 amp and that failed



i then went to 120 amp unit and that is doing the same thing. and i have that one excited at the plug on the side. the prm is 800 in gear at idle.



so has anyone else had this issue? today i took it out for the 1st time this year and on the way home i turned on the headlights and the voltage dropped to 12 volts at 30 mph. at a stop it dropped to 10 volts and the engine started misfiring.



so is there an alt that the corvair guys are using that actually works. it seems i should be getting close to 14 volts at speed. and maybe 13 volts at idle with the lights on.



my truck has the voltmeter and the volt meter hardly moves at speed or idle with or without anything on. i can turn on everything and it keeps the voltage up as close to 14 volts as it can.



now i still have the small pulley on it so it turns faster i have it excited thru the idiot light and still i have this issue



i rewired it because i was told that was the issue but that did nothing to help improve this. also i have talked to other car guys and they don't seem to be having this issue and they have alt with the larger pulley and they get 14 volts with everything on. it can't be due to running backwards as alt. don't care. my new wiring is heavier than stock for this reason. so any ideas thanks

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Re: alternator issue
Posted by: CoCoCo ()
Date: May 15, 2019 06:57PM

Well that is a strange one Bob. I was going to say you must have a wiring problem if four different alternators failed to charge at idle, but then you said it's all new and larger gauge.
It is entirely possible to get multiple bad new parts these days with the sad state of some parts affairs, but that many in a row? Very unlikely I'd think.

But seems you still might have other issues. An Ignitor should not burn out if the battery is capable of keeping it's 12v coming while the alter is not charging.
And you definitely don't have just an idle issue, since you said the alternator is not keeping up with load even when the engine is running at speed.

Have you tested any of these things? Voltage readings at the alternator for example? The lamp/exciter wire should have near enough to full battery voltage as to make no nevermind. The main charge wire should obviously read full voltage at both ends of course. But does it EVER read higher, up in the mid-14v range? What are it's readings at different rpm levels in neutral while you monitor?

Sorry I don't have any insight other than just a few of the basic questions. But if you have not already, maybe taking it down to the local parts store where they can test it'f function would be good. As long as the people there know how to use the test machine, you could get some good results.

Anything that can put out over 40a should be able to keep the battery fully charged under most normal circumstances. Unless you have a heavily electronic-ified Corvair, a 120 should be unstoppable once it's excited.

Good luck.

Paul

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Re: alternator issue
Posted by: corvairbob ()
Date: May 15, 2019 07:13PM

thans paul. i have 2 voltmeters on it one analog and one digital and htey are close to the same. i'm just about ready to go back the the regulator system with this. when i got the harness they made it up for me but they fails to remember i had a rear engine and i got shorted on some wires. anyway i have had this issue forever. i even reset the idle to 1200 rpm and then had to stomp the brake when at stops an that got old so i truen it back down. for the most part with the new 120 amp usnit it seemed to be ok but this year i noticed driving home with the lights on i was losing power. i check the belt and it is tight and still on. so it just may be possible the alt has failed. the lights are relay controlled so the power is not going thru the switch. i even turned on the fog lights and got the same thing. so i guess i will take it to the shop for testing and see if maybe something failed.

i asked because of the issues i was hoping someone may have the answer for unit that works. again thanks sooner or later it will get figured out.


the gang helped out on the fuel pump and that seems to be working great. after the over winter it started up fast and the new green acc pump cups that made a huge difference. glad they finally made those. thanks for that tip.

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Re: alternator issue
Posted by: MattNall ()
Date: May 15, 2019 07:19PM

You must have a tremendous draw somewhere...

I'd pull all the fuses and drive it... then replace... on by one..

MODERATOR
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Re: alternator issue
Posted by: corvairbob ()
Date: May 15, 2019 07:29PM

that matt it does it with the head lights the fog lights the fan. there is nothing else. the radio is after market and an amp the the amp is only running 6x9 speakers and it makes no difference it that is on or off. nor the radio.

it has done this for 3 alternators. the original alt. when i got it failed. so i went with the one wire. then i had to put on a smaller pulley, that caused the belt to rub the side of the crank pulley and left me on the side of the road. so i had to reposition the alt to align the belt. then i changed out the alt 2 more times. then someone here told me my wiring may be bad and causing this so i yanked it all out completely and did a 100% rewiring job. it then did better but at idle it would drop voltage, that is why i revved it up. but 1200 rpm's was just to much for me to hold at stops so i turned that back. so in neutral it reved to like 1500 and then in drive it was around 1100 to 1200 and i was told that was working the torque convert to hard. plus my foot holding it back.

i will take the unit to test tomorrow, it just may be that it failed and i then need to get it rebuilt. maybe an alt shop can set it up to charge good at idle. thanks

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Re: alternator issue
Posted by: Frank DuVal ()
Date: May 15, 2019 07:49PM

Well, based on people posting here, no one else is having a problem with multiple bad alternators.

My first question, is the engine grounded to the body of the car? On late models, the negative battery terminal has two wire, the large one goes to the left head, typically under the bolt holding the rear alternator bracket. The smaller wire attaches to the body on the frame rail beside the battery. Are these two wires in good shape and connected?

What voltmeter are you using, and have you calibrated it? I do not mean sending it out for a $100+ calibration lab work, but do you read several charged, but engine not running, auto batteries? What voltage did it read when doing this test.

And finally, what is the voltage reading of the Corvair with engine off, engine at idle and engine at 1500 rpm?

With engine on, at idle of 800 to 1000, check the voltage reading at the battery terminals and the voltage of the alternator (red lead on bolt, black lead on case of alternator. Do they agree? They should agree. If not, measure voltage, black lead on battery positive, red lead on alternator bolt. Then read voltage red lead on battery positive, black lead on alternator case. Post findings.

No way, unless you have a trunk load of added on after market accessories, do you need more than 40/45 amps, even with air conditioning. Stock Corvairs without AC get 37 amp alternators. They do just fine.

And finally, do yo still run an HRPT*? If not, how are the positive wires connected near the battery?

*HRPT : Horrid Red Plastic Thingy, named this on the Virtual Vairs email reflector system years ago. That red plastic connection near the battery.

And put the stock pulley back on. Only racers need to play with pulley size to reduce load of alternator on horsepower! Even the wrong alternator fan will not affect charge voltage, just cooling of the alternator innards.

Frank DuVal

Fredericksburg, VA



Edited 1 time(s). Last edit at 05/15/2019 07:51PM by Frank DuVal.

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Re: alternator issue
Posted by: MarkDustan ()
Date: May 15, 2019 08:05PM

I saw no mention of the battery. Shorted cell.

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Re: alternator issue
Posted by: Frank DuVal ()
Date: May 15, 2019 08:11PM

That's why I asked what the engine off battery voltage is.

Frank DuVal

Fredericksburg, VA

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Re: alternator issue
Posted by: MarkDustan ()
Date: May 15, 2019 08:13PM

I also hear the new electronic regulators fail often compared to the old factory mechanical ones

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Re: alternator issue
Posted by: Timothy Shortle ()
Date: May 15, 2019 08:18PM

Voltage drop? To check, hook up 1 end of your voltmeter to the positive post of the battery and the other end to the positive post of the alternator. Same on the negative side. 1 end to the negative post on the battery and the other end all around (to the frame/body, to the alternator case, etc.. You should read 0 or close to it on both tests.
Frank mentions the H R P T- it is nothing more than the positive junction point. What year and model do you have?

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Re: alternator issue
Posted by: David Malcolm ()
Date: May 15, 2019 08:44PM

I used a 3 wire internaly regulated alternator (later model Nova) and installed the jumpers as described in the Tech Guide. Did have a problem because I reversed the two smaller wires out of the alt. Didn't do any damage but I had a dead battery after a couple of days.I understand folks have had troubles with the 1 wire types.

David Malcolm
1969 Monza PG Coupe
NJ near the Meadowlands



Edited 1 time(s). Last edit at 05/15/2019 08:45PM by David Malcolm.

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Re: alternator issue
Posted by: corvairbob ()
Date: May 16, 2019 05:41AM

Frank DuVal Wrote:
-------------------------------------------------------
> Well, based on people posting here, no one else is having a problem with multiple bad alternators.
>
> My first question, is the engine grounded to the body of the car? On late models, the negative battery terminal has two wire, the large one goes to the left head, typically under the bolt holding the rear alternator bracket. The smaller wire attaches to the body on the frame rail beside the battery. Are these two wires in good shape and connected?

i have a 10 ga wire from the body to the engine on the right side the battery is grounded to the left side head the look to be in good shape



> What voltmeter are you using, and have you calibrated it? I do not mean sending it out for a $100+ calibration lab work, but do you read several charged, but engine not running, auto batteries? What voltage did it read when doing this test.

the voltmeter was in a cluster kit that most of the car guys around here use. because it shows 12 volts then 14 volts i can't tell exactly, so i installed a digital gage and that one is the same as a meter.



>
> And finally, what is the voltage reading of the Corvair with engine off, engine at idle and engine at 1500 rpm?

the battery now shows 12.81 at idle it was 13..52 at 2000 with everything on it was 11.82. but that was with the voltage drop i found in testing. explained below


>
> With engine on, at idle of 800 to 1000, check the voltage reading at the battery terminals and the voltage of the alternator (red lead on bolt, black lead on case of alternator. Do they agree? They should agree. If not, measure voltage, black lead on battery positive, red lead on alternator bolt. Then read voltage red lead on battery positive, black lead on alternator case. Post findings.
>
> No way, unless you have a trunk load of added on after market accessories, do you need more than 40/45 amps, even with air conditioning. Stock Corvairs without AC get 37 amp alternators. They do just fine.
>
> And finally, do yo still run an HRPT*? If not, how are the positive wires connected near the battery?

i installed a different hrpt much heavier duty but as i was getting the numbers i found that hrpt was hot. hot means voltage drop. the wires from the battery wer cold up to a resettable fuse i installed to protect the complete system like a fuse link. but after that i have that heavy duty hrpt. and that was hot. i felt the wires before and after that and they were cold so that may be the drop location.


>
> *HRPT : Horrid Red Plastic Thingy, named this on the Virtual Vairs email reflector system years ago. That red plastic connection near the battery.
>
> And put the stock pulley back on. Only racers need to play with pulley size to reduce load of alternator on horsepower! Even the wrong alternator fan will not affect charge voltage, just cooling of the alternator innards.

i had to reduce the pulley size to make the alt. rev to start charging. but to be honest now that i have it set to excite i may not even need that any more so i think i will just change it back and see how that goes.


picture show engine off voltage and where i got it from and engine at speed with everything on. but this was before i found the hot wire junction so now to fix that and post the results. thanks

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Re: alternator issue
Posted by: JimBrandberg ()
Date: May 16, 2019 05:59AM

I don't know that it's your trouble but one thing my engineering buddy said to do with a modern internal regulator alternator is to run the voltage sensing wire to a remote location, not just a pigtail at the alternator. He says it gives the regulator a better sense of the voltage in the electrical system. He's smarter than me with electrical stuff so I just do it.

I've been using a post junction block that mounts to the chassis with 2 screws and the post is insulated/isolated. It also takes the place of the horrible plastic thingy in LMs.

I've been using Wilson alternators from O'Reilly, a step above the cheapest. I did have one that wasn't charging which they replaced, I didn't tell them that I change them to a different base.

I finally bought a Multimeter last week when dealing with a 62 with a generator and the battery kept going down after a few days. I detected no milliamps of draw through the battery cable. It was supposedly a new battery, I gave it a good thorough overnight charge and I think the problem was solved.

I also just dig out the CORSA Tech Guide when wiring a conversion.

Jim Brandberg
Isanti, MN
CorvairRepair.com



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Re: alternator issue
Posted by: alphasud ()
Date: May 16, 2019 06:27AM

Frank is right. Voltage drop checks are critical to diagnose charging issues. 10ga from body to engine is a little weak. Also you currently have a 120amp alt. Installed how many wires other than the main B+ wire? If it’s a GM style they have different internal regulators and wiring. Had a customer install his own alt. On. G van. Plug was the same but internal regulator required different wiring. If it’s a 3 wire plug one wire goes to B+ and is the sense wire. Leave it disconnected and alt will never charge over 13.1 volts I believe. The other goes to the warning light and the 3rd is switched ignition. Other basic things are pulley slipping.

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Re: alternator issue
Posted by: corvairbob ()
Date: May 16, 2019 06:58AM

ok i think i found it. frank jogged my memory with that hrpt i checked the connections and they were a bit loose. i took them apart recrimped the fitting just to be sure they were crimped good and they were and then re assembled. i then restarted the engine and turned on all the power and it stayed at idle at 12.81 volts. that is enough for stops. then i revved it up to 2000k and the volts started to rise. as i turned off all the power users the voltage started to go up and with all of it off at idle i had 14.8 volts. i also did a temp scan and they now are 70 deg after running for 15 minutes. the alt was at 100 deg and the battery terminals were 75 deg. so i may have that loose connection now under control.

last year it was good so over the layup something changed. also on the hrpt i did have 2 nuts so that could have been the issue for awhile. i removed the nut and place the eyes together as they should have been from the start. my error on that.

the jumper from the engine to the body is larger ga that factory or at least what was there when o got the car.

also the hrpt i replaced with a much larger one but i did not do the proper assembly at that pint like i said my error. but frank jogged me on that so now it is correct.

lie i said i ran the engine with all items on lights fan radio with the amp doors ope and the fog lights. i did not run the ground effects as they are led and do not take much if anything besides i only run them with the engine off at show so i did not bother with them. but the alt did keep up and even rise when i set the speed to 2000k and it runs way more than that on the road.


so a great big thank you to all and frank for jogging my memory on that hrpt even though it has been replaced with a 100 amp junction unit.

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Re: alternator issue
Posted by: MattNall ()
Date: May 16, 2019 07:05AM

Great!! that's one I'll remember!

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: alternator issue
Posted by: Timothy Shortle ()
Date: May 16, 2019 07:20AM

Glad you got it fixed. I agree 10 gauge is a little "skinny". What size cable do you have between the battery and the starter? It looks small in the picture. I venture to say for 99+% of us alternator charging systems are a non issue.

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Re: alternator issue
Posted by: corvairbob ()
Date: May 16, 2019 07:22AM

yea thet one made me wonder. frank jogged my memory on the hrpt. even though i replaced that with a much larger heavy duty unit i did not assemble it correctly and cause that issue to show up. now it may have been there all along and the old hrpt was causing my issue back when and because i installed a new heavy duty unit it worked better but not like it should have due to my error so now with all the help and the kick in the pants i believe i git it. but time is going to tell one this one. but i will be keeping an eye on this for some time just to make sure it is still working correctly.

again thanks all for the help

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Re: alternator issue
Posted by: corvairbob ()
Date: May 16, 2019 07:25AM

Timothy Shortle Wrote:
-------------------------------------------------------
> Glad you got it fixed. I agree 10 gauge is a little "skinny". What size cable do you have between the battery and the starter? It looks small in the picture. I venture to say for 99+% of us alternator charging systems are a non issue.


that wire it the original typ wire that came in the car. i replaced it with another one later but it came from clarks for the car.

that 10 ga wire is the engine ground and is heavier than what was there in the beginning. thanks

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Re: alternator issue
Posted by: Richard ()
Date: May 16, 2019 09:45AM

PLEASE. Please STOP using that stupid home made acronym. It's a Junction Block.
I'm sure Duval meant it as a joke, but hardly worth repeating. I can't believe you picked that silliness and ran with it, repeating it thirty times!
GM and the whole World knows that as a Junction Block.

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