Best replacement alternator?

[dn010]

I've got an alternator that was originally purchased from Hervey many years ago. I've had three of them installed. I have a ground bus installed. And yet, when my engine is idling, none of these alternators have been able to maintain a nice output if I have the lights on or the A/C on. They all drop voltage, my lights dim, air motor slows down, until I push the accelerator to give me 1,000 RPMs then the needle bounces up and all is great. I have DPI fans, and even have my ECU programmed to bump the RPM up by 100 (850+- Idle RPM) when the A/C turns on yet I still have this issue. With no accessories turned on, my engine idles at 750+- and the needle is pretty steady with a good voltage.

It's been an annoyance from the beginning of ownership that I'd love to finally get resolved.

Can anyone tell me their experiences with other alternators? DMCH? Saturn alternator?

Thanks in advance

[Bitsyncmaster]

I now have the DMCH alternator and don't see any voltage drop after I connected the sense wire to the large post. I also run 850 RPM and bump to 950 RPM when the AC compressor is on.

[DMC5180]

Add the Red (sense)wire shown here, that is what Dave did.


https://uploads.tapatalk-cdn.com/20170922/e652c997505f455d36420e5ae1d5cee7.jpg

You can get a replacement connector loaded with all the wires like the one shown in the photo. Remove the 2 wires tied in the knot. They are not needed.

Also make sure the belt is tightened properly.

[dn010]

Thanks guys, I’m about to crawl under the car right now and give it a shot.


Sent from my iPhone using Tapatalk

[Bitsyncmaster]

Thanks guys, I’m about to crawl under the car right now and give it a shot.


Sent from my iPhone using Tapatalk

I had the Hervey alternator for about 7 years and I did not connect that sense wire. I connected the sense wire on the DMCH alternator to cure a voltage dropout every 18 seconds. It also fixed the flashing alternator light when you turn the key on. The DMCH unit has a fancy regulator in it that needed that fix.

[NckT]

Add the Red (sense)wire shown here, that is what Dave did.


https://uploads.tapatalk-cdn.com/20170922/e652c997505f455d36420e5ae1d5cee7.jpg

You can get a replacement connector loaded with all the wires like the one shown in the photo. Remove the 2 wires tied in the knot. They are not needed.

Also make sure the belt is tightened properly.

This is interesting, is this on the dmch alternator?

[FABombjoy]

The DMCH alternator looks like a GM style alternator and the sense line should be connected if possible, assuming they aren't custom built with sense connected internally. I recently reviewed datalogs from a DeLorean with a Hervey alternator and the voltage dropped to 12-ish during idle and rose to 14.4 off-idle.

I'm running a CS130 "Iceberg" alternator with a custom bracket, 105A rating. It's a wide ear mounting version of the common GM / Saturn alternator but rebuilt with better bearings and a special case to sink heat from the regulator better. I had to con Matt aka Drive Stainless into making it for me :D This opened up a universe with hundreds of options but took a bit of whittling to make it work. I could probably run an SI10, SI12, or CS144 as well.

With this alternator and the sense wire connected to the B+ post the voltage level finally hit 14.4 at idle. The moto was maybe high 13s at idle but the regulator potting was dripping out of the case so not a great reference.

[Bitsyncmaster]

This is interesting, is this on the dmch alternator?

Not sure if that is the same DMCH alternator but looks like the same connector. It's funny the sense wire used a larger pin and large wire but the sense only draws micro-amps of current. I guess they did that because you normally attach it to that large "battery" post.

[DMC5180]

This is interesting, is this on the dmch alternator?

The DMCH (CS130) is provided with same connector with only a single Wire (L) Since it technically does not need the (S) Red wire. However, when the key is turned to the Run position with engine off, the battery light will flash/pulse. Dave M. Added the Red sense wire to his DMCH alternator and the flash/ pulsing light stopped. Just a steady ON now.

As I mentioned earlier, too add the Red wire, you need to buy another connector pigtail assembly from your local AP store.

[DMC-81]

As an option, if you are looking for a connector to wire the S terminal to battery positive to at least the DMCH version, I got this Dorman 85854 WeatherPak connector which only has one extra wire to tie off/ cut. I'm not sure if it fits Hervey's.

53577

There is a full discussion in this thread: http://dmctalk.org/showthread.php?12181-DMCH-alternator

[dn010]

The connector is the same as Hervey's, it's also a GM alternator. I dug out the sense connector and crimped a wire to it, hooked it to the battery post. My results are somewhat better than before but still haven't solved the big drop with the AC - this time I have no drop with my lights on but still the big drop with the A/C compressor. Maybe my original compressor is going bad? If not then I guess it's time to try the DMCH alternator.

[ritztoys]

Just installed John Hervey's alternator, added my 'sense' wire/terminal to the Batt (+) and so far regulator acts as it should. At idle the gauge shows approx. 13v and it does drop when I turn on the A/C, but watching the gauge I can see the regulator 'kick in' bringing the voltage back to 13v. I will test again in traffic and other low idle situations. (car is still on jacks.)

Very happy 'D' owner! :thumbup:

[mluder]

AH-HA!
I have all these problems. The 18 sec interval drop and the power drain when I run lights, AC, etc. with the DMCH alt.
Sounds like the sense wire is the fix for me.

So I'll a wrench into the mix... I cannot undo the nut that holds the brown wires to the back of the alt. The post is spinning in the unit.
Any suggestions on how to get it off?

Cheers
Steve

[mluder]

Is this correct?
http://www.autozone.com/electrical-and-lighting/voltage-regulator-connector/duralast-voltage-regulator-connector/342423_0_8905

Cheers
Steven

[Bitsyncmaster]

AH-HA!
I have all these problems. The 18 sec interval drop and the power drain when I run lights, AC, etc. with the DMCH alt.
Sounds like the sense wire is the fix for me.

So I'll a wrench into the mix... I cannot undo the nut that holds the brown wires to the back of the alt. The post is spinning in the unit.
Any suggestions on how to get it off?

Cheers
Steve

Hold the wires (terminals) as you back off the nut. Make sure your battery is disconnected first.

[ritztoys]

AH- I cannot undo the nut that holds the brown wires to the back of the alt. The post is spinning in the unit.
Any suggestions on how to get it off?

I had the same problem, but the retaining nut was able to spin a little bit. So I held the Brown wires in a protective wrap(so to not damage wires) and held on tight. The 'stand-off' from inside my alternator began to loosen and back out w/Brown wire cluster attached.

Also that connector you posted is correct(For Hervey's alternator, you won't need that third wire, Brown w/White Stripe)

[mluder]

I had the same problem, but the retaining nut was able to spin a little bit. So I held the Brown wires in a protective wrap(so to not damage wires) and held on tight. The 'stand-off' from inside my alternator began to loosen and back out w/Brown wire cluster attached.

I'll give it a try - I did try holding the wires but they wanted to spin too. Need a little more brute force to keep them from moving I guess.


Also that connector you posted is correct(For Hervey's alternator, you won't need that third wire, Brown w/White Stripe)

Does it work for the DMCH alternator?

Cheers
Steven

[DMC-81]

Is this correct?
http://www.autozone.com/electrical-and-lighting/voltage-regulator-connector/duralast-voltage-regulator-connector/342423_0_8905

Cheers
Steven

Yes, that should work for the DMCH unit. You can compare it to the one that I successfully used:
https://www.dormanproducts.com/p-22865-85854.aspx

[mluder]

Yes, that should work for the DMCH unit. You can compare it to the one that I successfully used:
https://www.dormanproducts.com/p-22865-85854.aspx

Sure looks the same.

Cheers
Steve

[Chris 16409]

You can get the Dorman unit on RockAuto for around $5. Napa Auto Parts also stocks one.

[dn010]

I decided to revisit this yesterday after getting frustrated with voltage drops to 10 at idle even if it's just trying to power only the vent air motor on 1. I removed my air filter and filter shield (EFI setup) and found this which made me glad I checked.

56405

Regardless of this, I removed the alternator and disassembled it. The rear bearing is trashed. Maybe half of each brush was making contact with the rotor and the brush carrier was a little cracked and melted on the bottom. The alternator is done. I will be pulling my second alternator from my '57 Cadillac (originally a Hervey alternator I used to swap out the generator) to use for now until I can gather $200 for a new alternator.

[Chris 16409]

You can give this a try:

https://www.ebay.com/itm/140740542668

It's been tested to work in a friend's car. Just swap the pulley with the v-belt one on your old alternator.

[dn010]

Thanks for the link. I was about to click buy it now, until...

I recalled have two Volvo 780 Bertone alternators. Didn't have a clue if it would fit or not but after a forum search it seemed there was a good chance. So, I grabbed one of them and started to compare it to the old alt and it looked good. I installed it. It bolted right up to the original mount without a spacer. I will have to figure out a bracket, I have a few different ones so I'm sure I have the original somewhere. Wired up the two battery wires to the main connection bolt, and then crimped a connector to fit the blade fitting sense connection. Started the engine. No charge. I checked the connections and did it again but still got no charge until I got some RPMs on it to excite, now it is charging beautifully! My gauge is not at all accurate but readings from the battery look pretty good to me. I can have everything possible on and get over 13V although the gauge doesn't show it. I can have my lights on and they won't dim at idle - I'm not really sure how to take this, it will be a while to get used to having a good charging system...

Some photos:

Comparing the old Hervey alt to the Volvo 780 Bertone one:

56415

Some shots of it

56416

56417

Installed, without adjusting bracket at this time:

56418

Everything on at full tilt and a shot of the inaccurate gauge:

56419

Everything off:

56420

Everything possible on @ idle:

56421

Everything possible on at 2000 RPM:

56422

I'm off to either find or make a bracket so that I can bring my son to his last day of 4th grade tomorrow and make his day!

EDIT: I like to add that my fuel injectors (EFI) are really enjoying the reliable power as well!

[Chris 16409]

The DeLorean gauges were never super accurate. As long as the alternator shows it's outputting enough on the multimeter, you may have to accept the lower dash reading. Part of the problem may lie in all the common grounds that join up at the instrument cluster. After discussing things with Dave M in the past, he believes you can get a higher dash volt reading if the fule pump is given a dedicated ground. Normally the pump is grounded along with the other instruments. I've relocated my fuel pump ground to the shift plate, and noticed a difference.