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Alternator/Charging Gurus please help! Long..

Posted By: W5Duster436

Alternator/Charging Gurus please help! Long.. - 02/19/10 01:46 AM

Having some issues with the charging system after putting a new engine in this winter. I also changed to a march serpentine system so I had to take the alternator to a shop to get it pressed on. They broke the original front housing so they put another on. This may all be a grounding issue as I only have the ground from the battery to the aluminum head. Checking continuity from anywhere on the engine to the regulator appears fine. The only other thing that changed is the addition of an aeromotive fuel pump and the relay is triggered from the 12v going into the ballast. The ignition is triggered from the original 12v coming out of the other side of the ballast.

Here's where the fun starts..

Took the car for a ride and it appears to charge fine until I stand on it and around 4K it would absolutely peg the amp gauge out until I pressed in the clutch and let the rpm's come down quickly. After doing this a few times I decided to put my multimeter on the battery and strap it to my windshield. Slowly going to 4K it would reach that point or close and then bury the ammeter again and also run the voltage to 18-19 instantly (full field basically).
Went and bought a new regulator and wire brushed the firewall to ensure a good ground as well. Another ride still had the same problem.

I then decided to try changing the fields and took it for another ride and slowly took it to 4k and it didn't bury the ammeter. I decided to step it up a bit and when I hammered it the ammeter this time completely went to discharge and basically killed the electronics and the engine died.. pulled both fields and drove it home. Took the alternator back to the shop where they changed my melted brushes from the full field runs. They then tested the alt with a new reg on the bench and ran it up to the fastest speed that the bench would do and it held steady at 14.5 volts or so.

Brought it home and hooked it back up again and took it for a ride and still the same thing. Driving around normally everything is great but once you step on it the thing discharges fully and cuts the ignition/lights out.

I'll try running another strap from the block to the firewall to be sure but what really baffles me is why does changing the field wires make it either completely charge or discharge?

Sorry for the novel. Help..
Posted By: RapidRobert

Re: Alternator/Charging Gurus please help! Long.. - 02/19/10 02:31 AM

It was an interesting novel .Pull the brushes again & see if they're good then take off the VR triangle plug and the 2 alt field female leads and use jumper(s) to connect (1) either alt male field terminal AND the "blue wire" male pin on the VR both of them to the batt positive post and (2) connect the other alt male field terminal to the "green wire" male VR terminal then take her out & if not good might also connect the batt positive post to the alt batt terminal. You've replaced the alt/reg and the ground circuit appears to be OK so this will check the positive half of the circuit.
Posted By: riverman

Re: Alternator/Charging Gurus please help! Long.. - 02/19/10 02:39 AM

When an alternator goes on full charge, its because the field is grounded. The only thought I have is that you when go to high revs, something in the alternator "flies out" and grounds the field. When the shop tested it it didn't rev high enough and did not have the vibration associated with being in the car. Coupled with their crunching the front of it and getting into the internals might point to the alternator is at fault. Just got a rebuilt one at Advance for $55 which may be a cheaper and less aggravating fix than going through ballast resistors, regulators, etc. My , I'm no expert. See how others weigh in.
Posted By: W5Duster436

Re: Alternator/Charging Gurus please help! Long.. - 02/19/10 02:43 AM

Quote:

When an alternator goes on full charge, its because the field is grounded. The only thought I have is that you when go to high revs, something in the alternator "flies out" and grounds the field. When the shop tested it it didn't rev high enough and did not have the vibration associated with being in the car. Coupled with their crunching the front of it and getting into the internals might point to the alternator is at fault. Just got a rebuilt one at Advance for $55 which may be a cheaper and less aggravating fix than going through ballast resistors, regulators, etc. My , I'm no expert. See how others weigh in.




I would have already replaced it as well but the issue is the darn march pulley that I just bought. I am afraid that if I buy another alt it'll get destroyed again trying to put this pulley on. I guess if I could buy one I'd just get a powermaster straight from Mancini with a one wire setup and no pulley. Just not sure if I can purchase an alt without the pulley unless I go straight to powermaster I guess.

BTW, this was my thought too that something in the rectifier or something else inside the alt is causing the issue. When I took the alt back they spun it pretty darn fast and it held steady at 14v or whatever. I mean that little thing running the alt sounded like a jet engine. It had to be flying.

Also agree it was going to full field but WHY would it go the opposite when changing the field wires? That makes NO sense whatsoever.
Posted By: RapidRobert

Re: Alternator/Charging Gurus please help! Long.. - 02/19/10 03:31 AM

Quote:

Also agree it was going to full field but WHY would it go the opposite when changing the field wires? That makes NO sense whatsoever.


What Riverman says makes sense that the "full fielding" and the "open" opposites are happening inside the alt but you'd think their bench test would have duplicated it. I'd sure think a shop ought to be competent to R&R a serpentine pulley (I would split the alt you want the serp pulley installed on, apart & give them the pulley half) as it has to be apart for this. replacing the wires w jumpers would eliminate that system and be easier than R&R ing the alt. Holler when you find it.
Posted By: ahy

Re: Alternator/Charging Gurus please help! Long.. - 02/19/10 03:34 AM

Agree the alternator is highly suspect. The serpentine pulley would be a lot easier with a bolt on type pulley set-up. Autozone could change the pulley for you. Just takes a calibrated impact wrench. Depending on your engine combo, the Powermaster small case Delco Chrysler replacement alternator may work.

Or just find a better shop to press on the pulley and a new alternaotr. I believe the alternator is supposed to be disassembled for pulley press so only the shaft takes the force. No effect on the housing at all. Your guy apparantly didn't know this. Who knows what got bent/screwed up.
Posted By: W5Duster436

Re: Alternator/Charging Gurus please help! Long.. - 02/19/10 04:15 AM

Quote:

Agree the alternator is highly suspect. The serpentine pulley would be a lot easier with a bolt on type pulley set-up. Autozone could change the pulley for you. Just takes a calibrated impact wrench. Depending on your engine combo, the Powermaster small case Delco Chrysler replacement alternator may work.

Or just find a better shop to press on the pulley and a new alternaotr. I believe the alternator is supposed to be disassembled for pulley press so only the shaft takes the force. No effect on the housing at all. Your guy apparantly didn't know this. Who knows what got bent/screwed up.




All the shops I called knew it had to be taken apart to do the deed and this shop was no exception they stated that it is very common to break the front part of the housing when trying to remove the pressed on v-groove pulleys. I didn't understand why either since you put something under the pulley and press the shaft through but who knows.

I hate to spend the $ but it appears that March actually sells an 80 amp or so single wire alt. with the pulley already attached. May save me $ in the long run by going that route instead of buying multiple rebuild and having shops press on this pulley. Dunno.
Posted By: RapidRobert

Re: Alternator/Charging Gurus please help! Long.. - 02/19/10 04:14 PM

Quote:

they stated that it is very common to break the front part of the housing when trying to remove the pressed on v-groove pulleys. I didn't understand why either since you put something under the pulley and press the shaft through but who knows.


From what I understand they use a mini gear puller thingy that's for our alt pulleys for the removal & you're not putting pressure on the housing half
Posted By: W5Duster436

Re: Alternator/Charging Gurus please help! Long.. - 02/19/10 11:00 PM

Called another shop in the area today and he couldn't believe that the other shop had broken the alt. Said that sounded like BS. He also stated that even though it sounded like it was spinning fast it probably wasn't going anywhere near as fast as it would be on the engine.

In his opinion the first thing he said is that he's had to replace several that the tolerances were off on some of windings and at high rpm they'll short out inside the case. So before I shell out for the March Alt. I'll let them have a look at this. This one actually might not even be 60amp as a rebuilt unit. Either way they'd fix me up with at least an 80amp unit that won't short out etc.

Fingers are crossed.
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