Box Alternator Question

[friskyfrankie]

A friend of mine, with an '87 CV, asked me: How powerful of an alternator can be installed and still maintain the OEM wiring harness? I figure anything up to 75 Amp would fit the bill but was wondering if anything stronger would also work. I remember, the Canadian ones with the heated windshield came with 100 Amp alternators. Thoughts??

P.S. I know of the 3G conversion option but he wants to keep the OEM harness (of course with that connector waiting to combust, I don't know why).

[sly]

With those stock connectors... 65 amp stock is almost too much. Any upgrade will be dangerous without converting to a bolt on charge cable. And if you're going to add a better charge cable, might as well do the 3G swap because it's just one additional wire to be modified. http://www.grandmarq.net/vb/showthre...upgrade-README

Also, there is no need to remove the old charge cable. I never did. I just ran the new one and disconnected the old one at the post on the starter solenoid.

The 100A alternators are a 1G alt with bolt on charge cable and do not have fire issues.

[Kodachrome Wolf]

The 100 amp heated windshield cars use the 1G alternator and an external voltage regulator, so their wiring is a little different.

Honestly if he's keeping the factory harness, then a factory 2G is all he gets, that wiring really won't take more.

When doing a 3G swap, one could just tuck the factory charge connector out of the way. The voltage regulator connector is the same, so that doesn't really need anything changed except disconnecting the stator wire from the old charge plug and attaching it to the single pin connector that loops into the 3G. Then all you need to do is run the charge cable. Understandable if he doesn't want to go that route though.

[Tiggie]

I like stock stuff but there is no reason to keep a 2G. It's just not safe with the age and inferior design. I had one light up on a parts car, and I had a friend lose his nice 90 to an underhood fire caused by the darn thing.

The 3G looks good with a SEFI car. Talk your friend into an upgrade!

[VicCrownVic]

In addition to the wiring differences for the 100 Amp alternator for Insta-Clear windshield equipped panthers, there is also a different support brace to clear the case of the 100 Amp alternator.
+1 on the charge wiring for a stock 2G equipped vehicle not going to handle much, if any, more amperage than stock.

[gadget73]

Did the 2G even exist in other sizes besides the 65 ?

but yeah I echo the other comments about it being a flaming turd. Mine got upgraded when the harness melted down on the way to a meet. Car died at the light right in front of the place, had to get jumped to get in. Scott helped me cobble the harness together enough that it would run to get to a mutual friend's place then he helped me convert the thing over in the driveway.

[friskyfrankie]

Thankfully, he has never had a under hood "barbecue" and has had the car since new. Doesn't mean it can't happen but currently he has his mind set on leaving it stock (although I agree with the consensus here about the 3G). I think he currently has a 60 Amp one in now and wanted to possible go up to 75. I think 65 is standard.

[jaywish]

IIRC there are replacement plugs with pigtails that can be used to decrease the likelihood of fire. Perhaps others will comment on that. I side with doing the upgrade to 3G.

[friskyfrankie]

IIRC there are replacement plugs with pigtails that can be used to decrease the likelihood of fire. Perhaps others will comment on that. I side with doing the upgrade to 3G.

Would be interested in knowing that. I believe most are designed to "melt" first, like a fuse, in order to save the rest of the system but I have heard that may not always work as I am sure some here can attest to!

[Mainemantom]

I have new replacement pigtails available. They came with new/reman. alternators many years ago. Contact me if interested.
I agree with changing the alternator and wiring to 3G. Far better and safer.

[friskyfrankie]

I have new replacement pigtails available. They came with new/reman. alternators many years ago. Contact me if interested.
I agree with changing the alternator and wiring to 3G. Far better and safer.

Are the pigtails you have the same design as the ones available everywhere are are these special to resist melting and shorting out?

[Mainemantom]

I believe these to be the same design. Since they have not been used they would be better than the original. I can't be responsible for any mishaps. The alternator system needs to be replaced asap if not sooner.

[friskyfrankie]

I believe his alternator was replaced, a few years ago, so he does not have the original connector. Haven't been able to convince him to do the 3G conversion yet but am working on it!

[gadget73]

The fix was to eliminate the plug entirely and hard-wire the alternator. You'll find that on replacements sometimes, wires coming out of the spot where the plug should be and the opening sealed up with epoxy. Cut the crimps when it dies. Not exactly my idea of a proper solution.

[kishy]

Just so there is no confusion here, because this seemed to be hinted at above:
The plug melting is not an intentional feature, and neither the melting nor fire result from an electrical short. They result from excess heat that goes outside of the design specifications for these parts.

The terminals for the alternator charge harness are spade terminals. In the original design, when originally manufactured, they are adequate for their job, but have essentially zero margin to accommodate for the aging of these parts and the harsh environment they live in.

Engine vibration and thermal cycling (though a combination of heat normally present in the engine bay, as well as heat from carrying current) causes the spade terminals to lose their firm grip and become "wiggly". This loosened contact makes them get even hotter from trying to carry the same current, and the cycle repeats until they make quite poor contact and get quite hot, which causes the melting and eventual fire hazard.

If someone is hell-bent on keeping the car "unmodified", replacement of the alternator and charge connector should probably become a scheduled maintenance item, maybe yearly. Knee-jerk overreaction? Maybe, but no more senseless than the choice to keep the 2G. There is no viable way to monitor the condition of the connector, because disconnecting it to look at it will contribute to the problem developing. By the time it gets visibly melty, the actual problem has been brewing for a long time.

Additionally, regardless of the alternator on the car, driving a classic car carries some responsibilities over and above just driving some 2021 whatevermobile. The operator of the vehicle should have basic mechanical and electrical knowledge of the systems of the car, and the vehicle must always be equipped with a fire extinguisher that the operator is familiar with the location and use of. On a long drive, I carry two.