Alternator replace, advice please

[ArdWrknTrk]

Jim - I had to go back to the 3G Alternator Conversion page to see the context, which is:

In that pic his thumb is on the output cable coming from the alternator and it is pointing at a 175 amp fuse in a nice holder that can be mounted on your inner fender near the starter relay. And his pointer finger is touching the stator connector and pointing at the regulator connector. Everything you need in one go.

But, there are other Ford harnesses available. Here's one I found on a Ford in the salvage. In this one you can clearly see the white/black stator wire coming out of the alternator and wrapping back to go into the alternator at the regulator plug. And, you can see the yellow/white that comes from the regulator's plug and is connected to the big output terminal. (If you look closely, in the picture above the yellow/white wire connects to the alternator side of the fuse and is protected by the 20 amp fuse in the fuse holder.) But, my harness does not have a fuse, and some form of circuit protection is absolutely necessary. See below.

And I do see the problem. The "and some form of circuit protection is absolutely necessary" was intended for the output wire, not the sense wire. But the way it is written it seems to be saying that circuit protection is absolutely needed for the sense wire.

So I like your upgrade, but maybe it should be something like:

If you look closely, in the picture above the yellow/white wire connects to the alternator side of the fuse and is protected by the 20 amp fuse in the fuse holder, but my harness does not have a fuse.

That fuse failing would lead to an overcharge situation because the regulator would not sense any voltage in the truck or battery.

But some form of charge circuit protection, meaning in the output wiring, is absolutely necessary. This can be a 175A Megafuse, or a 150A circuit breaker inline with the thick charge cable as shown below

Obviously since we've suggested that the sense wire be wrapped back to the output we don't think protection on it is necessary, much less absolutely necessary. So I'm glad you caught that.

I *didn't* catch it.

In fact I looked right past it even when Buggtruck pointed it out.

But I do see where his confusion came from.

Whatever you see fit is fine with me.

[Steve83]

I *didn't* catch it.

In fact I looked right past it even when Buggtruck pointed it out.

But I do see where his confusion came from.

Whatever you see fit is fine with me.

I just skimmed this thread - I've been busy/offline/fighting with the local cable company for the past few days, so I'm not sure if this has already been answered, but...

The little 20A fuse in my photo of the Expedition alternator harness protects that wire for the alternator ROTOR and voltage regulator (the INput side). If it blows, alternator output goes to 0, just like if the 175A fuse blows. The only way the alt will go to max output is:

1) the VR detects that it's needed, based on the system voltage; or

2) the VR is bypassed by grounding the F screw (the one labelled "GROUND HERE TO TEST" on factory VRs).

[ArdWrknTrk]

I just skimmed this thread - I've been busy/offline/fighting with the local cable company for the past few days, so I'm not sure if this has already been answered, but...

The little 20A fuse in my photo of the Expedition alternator harness protects that wire for the alternator ROTOR and voltage regulator (the INput side). If it blows, alternator output goes to 0, just like if the 175A fuse blows. The only way the alt will go to max output is:

1) the VR detects that it's needed, based on the system voltage; or

2) the VR is bypassed by grounding the F screw (the one labelled "GROUND HERE TO TEST" on factory VRs).

Steve,

I apologize.

In BuggTruck's thread he said the 20A fuse was in the Y/W wire.

Gary didn't seem to disagree and I'm waiting for pictures to fill on my phone.

So if you're saying the fuse is in the LG/R wire (which is what I said in the first place) then no harm would be done.

[BuggTruck]

Okay, update. Got the alternator off (and learned some new words 🤬) New wires should arrive tomorrow. Until then heres a rundown of what i need to do, and what i need to buy.

Replacing all my belts while i have them off anyway, one was cracking.

Found power steering leak, its the high pressure hose gasket at the pump. But i dont think they sell just the gasket, have to replace the whole hose 😑

Doing oil change.

Washed down engine compartment while its hot outside and truck has no power.

Doing a quick cooling system flush and replacing the thermostat. Then finally going to hook up my new heater core.

Checking vacuum hoses, i think theres a leak...

New alternator is not threaded on the ear. I have to go to hardware store and find acceptable washer, bolt, and nut. This would be a nice mention on the write up. Would save a few minutes anyway.

I can not get the stupid pulleys off the alternator. I know a mechanic i am going to talk into switching them for me in the morning.

I regret trying to make the charging cable, should have just bought one. Its fine, just a pita to do and I'm tired now.

Where can i get a spacer for the pully locally? Hardware store? Oreilys?

[BuggTruck]

A 3g upgrade is very popular on the oddly similar Mustangs of comparable years. They are fords after all and suffered from the same poorly designed alternator. And mustang owners make better YouTube videos than ford truck owners. Posting some videos for reference i thought were informative ( and one pointless one where the alternator is dismantled and turned into an engine). Mustang's though have the battery on the driver side. Weird.

I had 2 other mustang 3g videos but one simply reused the 2 current charge cables (thats bad 😮) and the other used a new alternator with an external regulator.

[ArdWrknTrk]

Okay, update. Got the alternator off (and learned some new words 🤬) New wires should arrive tomorrow. Until then heres a rundown of what i need to do, and what i need to buy.

Replacing all my belts while i have them off anyway, one was cracking.

Found power steering leak, its the high pressure hose gasket at the pump. But i dont think they sell just the gasket, have to replace the whole hose 😑

Doing oil change.

Washed down engine compartment while its hot outside and truck has no power.

Doing a quick cooling system flush and replacing the thermostat. Then finally going to hook up my new heater core.

Checking vacuum hoses, i think theres a leak...

New alternator is not threaded on the ear. I have to go to hardware store and find acceptable washer, bolt, and nut. This would be a nice mention on the write up. Would save a few minutes anyway.

I can not get the stupid pulleys off the alternator. I know a mechanic i am going to talk into switching them for me in the morning.

I regret trying to make the charging cable, should have just bought one. Its fine, just a pita to do and I'm tired now.

Where can i get a spacer for the pully locally? Hardware store? Oreilys?

The pulley will come right off with an impact wrench.

(I'm surprised Gary didn't mention this. I suppose us old dogs are too familiar)

Most autoparts stores do this every day when a customer brings in their old core for a reman.

The shim Gary shows is from Home Depot. If you zoom you can see the number and SKU.

Any good hardware should have shims.

Edit: I'm wrong .. You need a 17mm (~11/16")ID and perhaps 1.25mm (0.050") thick.

When the old V-belt pulley goes on there won't be many threads for the nut.

Mines been fine for years since its only loaded one way. If it troubles you, use blue threadlocker.

I thought I did mention which Lester #'s were threaded 8x1.25 and which were not.

Maybe that was the other thread? Sorry...

Ask your mechanic friend to tap the ear 3/8-16 **or install a 3/8-16 Helicoil** and you can use your old bolt. (he doesn't even need to drill it out, the tap will go)

Be very careful replacing the thermostat in Windsors.

Use an adhesive gasket to hold it in place.

If it falls down and you tighten the housing you'll crack it. Damhik

Yep. That's why I said in the other thread to buy a ready made 4Ga. cable at the parts store....

I loved the video of the kid zooming around his neighborhood in an electric cart when I first saw it.

It shows you how much power an alternator can take (and why a single belt V-belt will slip above 90A)

[ArdWrknTrk]

An additional note to Gary about the alternator interchange...

The Lester #'s for 130A 8.25" alternator are: 7771 for non-threaded and 7765 for the 8x1.25.

Ahhh. So I did mention threaded v/s not threaded in post #3.

Better to get it tapped 3/8 because 8mm is very sloppy in the adjuster slot.

I was going to mention your power steering leak as well but didn't want to come off as picking on you.

[85lebaront2]

A 3g upgrade is very popular on the oddly similar Mustangs of comparable years. They are fords after all and suffered from the same poorly designed alternator. And mustang owners make better YouTube videos than ford truck owners. Posting some videos for reference i thought were informative ( and one pointless one where the alternator is dismantled and turned into an engine). Mustang's though have the battery on the driver side. Weird.

I had 2 other mustang 3g videos but one simply reused the 2 current charge cables (thats bad 😮) and the other used a new alternator with an external regulator.

Some of us do not watch YouTube videos on how to do things, we are old fashioned and prefer it in print. That way if you need to go back to look at something it is easy to do. I did my 3G conversion shortly after my MAF/SEFI conversion on Darth. I had the 2G and harness from the parts truck on initially and since the whole front harness had been updated I didn't have the strange in and out of the alternator harness to deal with. The later trucks essentially have the alternator harness as a completely separate item, only the green/red power from the idiot light connects to the front harness, the output goes directly to the hot side of the starter relay. On the 2G it still had the fusible links, but the yellow/white wire is connected to the two black/orange wires before the fusible link, not after it. At least on these a blown fusible link on the alternator will not cause it to to go crazy trying to charge through an open circuit like the Bullnose system will.

[Gary Lewis]

The pulley will come right off with an impact wrench.

(I'm surprised Gary didn't mention this. I suppose us old dogs are too familiar)

Most autoparts stores do this every day when a customer brings in their old core for a reman.

The shim Gary shows is from Home Depot. If you zoom you can see the number and SKU.

Any good hardware should have shims.

Edit: I'm wrong .. You need a 17mm (~11/16")ID and perhaps 1.25mm (0.050") thick.

When the old V-belt pulley goes on there won't be many threads for the nut.

Mines been fine for years since its only loaded one way. If it troubles you, use blue threadlocker.

I thought I did mention which Lester #'s were threaded 8x1.25 and which were not.

Maybe that was the other thread? Sorry...

Ask your mechanic friend to tap the ear 3/8-16 **or install a 3/8-16 Helicoil** and you can use your old bolt. (he doesn't even need to drill it out, the tap will go)

Be very careful replacing the thermostat in Windsors.

Use an adhesive gasket to hold it in place.

If it falls down and you tighten the housing you'll crack it. Damhik

Yep. That's why I said in the other thread to buy a ready made 4Ga. cable at the parts store....

I loved the video of the kid zooming around his neighborhood in an electric cart when I first saw it.

It shows you how much power an alternator can take (and why a single belt V-belt will slip above 90A)

Ok, we have several upgrades for the how-to: impact for the nut; including the part # for the spacer in the write-up instead of relying on seeing it in the pic; and maybe links to some of the videos.

However, I think the videos help us understand which engines take which size alternator.

But it irks me that the guy keeps calling a female terminal a "spade" terminal. He should try digging with a shovel shaped like that terminal.

[ArdWrknTrk]

Ok, we have several upgrades for the how-to: impact for the nut; including the part # for the spacer in the write-up instead of relying on seeing it in the pic; and maybe links to some of the videos.

However, I think the videos help us understand which engines take which size alternator.

But it irks me that the guy keeps calling a female terminal a "spade" terminal. He should try digging with a shovel shaped like that terminal.

A spade *connector* is both sides.

Spade socket????

(I didn't watch any of the videos)