Alternator Capacities For '88 CV

[Mainemantom]

When the LMR 3 G swap was done on both TCs, I used a 51 inch Carquest 5060510 belt. Bought an extra one as a spare.

[friskyfrankie]

When the LMR 3 G swap was done on both TCs, I used a 51 inch Carquest 5060510 belt. Bought an extra one as a spare.

Good to know - thanks Tom! Still would like to keep the same belt with an alternator that fits without cutting the frame but I do like getting everything in one kit. We'll see....

[gadget73]

I can't recommend using both the original charge wires and an additional. It makes fusing the thing with any degree of certainty impossible. There are two paths for current to flow and two different fuses involved. The chances of them opening at any sort of predictable current level is basically zero. Has to have one fuse for all of the current to flow through if its going to work properly.

[friskyfrankie]

I can't recommend using both the original charge wires and an additional. It makes fusing the thing with any degree of certainty impossible. There are two paths for current to flow and two different fuses involved. The chances of them opening at any sort of predictable current level is basically zero. Has to have one fuse for all of the current to flow through if its going to work properly.

Agree completely. Perhaps the posters were referring to keeping the original wires in place but not being connected at either end?

[gadget73]

wishful thinking, but knowing what I know about how little people understand electricity, I'm not keeping my hopes up.

[DerekTheGreat]

I can't recommend using both the original charge wires and an additional. It makes fusing the thing with any degree of certainty impossible. There are two paths for current to flow and two different fuses involved. The chances of them opening at any sort of predictable current level is basically zero. Has to have one fuse for all of the current to flow through if its going to work properly.

I think of it this way: Electricity now just has multiple paths to flow and we know it'll choose the path of least resistance. It's like adding three lanes to a two lane highway, for a total of five. The wires (lanes) are fused to their limit, but with there being additional paths none of them should even be close to their capacity. Why I've added that I've had the swap done for some six or seven years now with 40K+ miles on the clock. At one point the car did something like 25 hours non stop on the road too, with every accessory save the wipers and rear defrost going and no issue.

[gadget73]

it doesn't chose the path of least resistance. It takes all paths. A 100 amp fuse in parallel with a 150 amp fuse doesn't neccesarily mean its going to blow at 250 amps, and thats the problem. You can't know exactly when its going to pop the fuses.

it will work just fine until something goes wrong and you need that fuse to blow. Whether the circuit opens or not before something catches fire? who knows.


fuses are basically like insurance. Completely pointless right up to the moment you need it.

[kishy]

In the context of a factory 2G car which is retrofitted with a 3G with a new additional charge cable and the 2G original wiring is left in the car:

There is no parallel path if the 2G original charge cable is not connected to both ends, and it is not in my case. The 2G plug is still on the end, ziptied away nearby in case a 2G needed to be put back on the car. For context, at the time I did this, it was the only car (what a simple time that was) and roadside repairability was a priority.

It remains connected at the starter relay, which is not ideal but since it's fused it's also inconsequential. I believe I did this because it was not apparent how far into the loom I'd have to go to find the splice for the regulator's voltage sense wire.

Agreed that it is bad to (intentionally or otherwise) create a higher-capacity and overfused mixture of paths for current to take.

[DerekTheGreat]

it doesn't chose the path of least resistance. It takes all paths. A 100 amp fuse in parallel with a 150 amp fuse doesn't neccesarily mean its going to blow at 250 amps, and thats the problem. You can't know exactly when its going to pop the fuses.

it will work just fine until something goes wrong and you need that fuse to blow. Whether the circuit opens or not before something catches fire? who knows.


fuses are basically like insurance. Completely pointless right up to the moment you need it.

"Chooses the path of least resistance" was a bone head thing for me to say, and I wasn't trying to say that now I've got a 250 amp circuit. What I was trying to say was akin to the freeway example, that the electric current has additional paths to take instead of the one. Like stepping up to a 5/8th's hose over a 1/2 inch. 100% of the alternator's output is not going to go through the old charge wires nor will it go through the wire originally supplied for the 3G that I added, it's going to go between both. I am an idiot, but I'm trying to understand how that isn't the case. In my head it plays out like this, "We use a fatter gauge wire to carry more current, so why wouldn't a bunch of smaller gauge wires that if combined would total or exceed the gauge rating of the single fat wire carry the same current without issue?"

[sly]

+1 I left the original wiring in there but disconnected it at both ends when I did the swap.

[GM_Guy]

Wonder on the '94-99 Taurus if you can use the pulley that comes with it of if need to swap the one from the original '87/'88. As you can guess, I am trying to make the swap as painless as possible. Not really interested in doing all kinds of "unnatural acts" to make it all fit.

1995 Taurus is the large frame 3G (I put one on my mgm). You will need to use your original pulley as the taurus pulley has a larger diameter and you will need to find an upper bracket (the one with the adjuster slot) from a 100amp equipped cvgmtc.

[friskyfrankie]

Good details! How about simply finding an alternator (3G) that is the same size and only swap the pulley, if required?

[kishy]

1995 Taurus is the large frame 3G (I put one on my mgm). You will need to use your original pulley as the taurus pulley has a larger diameter and you will need to find an upper bracket (the one with the adjuster slot) from a 100amp equipped cvgmtc.

Sorry for the nitpick:
1995 Taurus is one of my donor vehicle preferences and it is definitely the small frame 3G, when equipped with the Vulcan 3.0 OHV, and that alternator is the right size for direct fitment into our stuff (with the caveat about possible bracket grinding).

1995 Taurus with a 3.8 is the big alternator, but in all my junkyarding history, I've probably seen 2 of those cars with that engine.

I have in one case been able to use the Taurus pulley and in another been unable to, and never could make heads or tails of why there was a difference.

[aharonLTC]

3.8 has the large case
3.0 has the small case

I just installed a small case in my 87.

[friskyfrankie]

So my understanding is the '95 Taurus with the 3.0 has the correct size alternator that does not require bracket grinding/alteration and is therefore a direct fit? Pulley swap is cool if a direct fit.