Alt belt.

[Ifitaintbroke]

Been reading about the 3g swap, which I have done. It seems that others have used a single v belt with no problems? I currently have an oversized pulley which works fine, but I'm concerned the alternator work put out as much at peak because of the reduced speed. When adding more loads(winch), I know I'll need more output. I've thought of trying a small engine belt(the green kind), as I believe they are higher friction, and a normal sized pulley. Thoughts?

[Gary Lewis]

A box stock 3G alternator puts out 106A @ 1600 alternator RPM, 134A @ 2500 alternator RPM, & 160A @ 6000 alternator RPM. And Ford put a 3:1 ratio on the 460's, so maybe your pulley isn't too large?

As for the belt, I've read that a single v-belt is not supposed to be able to handle more than about 100 amps. But people seem to make it work fine all the time, so I'd give it a try. If it doesn't work then you might look for the right pulleys to do two belts, but take it from me that isn't easy to do.

[Ifitaintbroke]

A box stock 3G alternator puts out 106A @ 1600 alternator RPM, 134A @ 2500 alternator RPM, & 160A @ 6000 alternator RPM. And Ford put a 3:1 ratio on the 460's, so maybe your pulley isn't too large?

As for the belt, I've read that a single v-belt is not supposed to be able to handle more than about 100 amps. But people seem to make it work fine all the time, so I'd give it a try. If it doesn't work then you might look for the right pulleys to do two belts, but take it from me that isn't easy to do.

I tried the stock pulley when I first did the swap and it squealed like crazy. The pulley I have is about twice the diameter of the stock one, so rpms are cut in half. I'll have to do the math on that based on what you just said, but that may take a few minutes as math was not my favorite subject.

[Gary Lewis]

I tried the stock pulley when I first did the swap and it squealed like crazy. The pulley I have is about twice the diameter of the stock one, so rpms are cut in half. I'll have to do the math on that based on what you just said, but that may take a few minutes as math was not my favorite subject.

The 3G comes online immediately, so when starting the truck it'll try to "fill the battery back up" very quickly. That'll make the belt squeal for sure. The fix for that is one of soft-start regulators, which are technically called LRC. This search shows several of them available from 2 seconds to 10 seconds.

[Ifitaintbroke]

The 3G comes online immediately, so when starting the truck it'll try to "fill the battery back up" very quickly. That'll make the belt squeal for sure. The fix for that is one of soft-start regulators, which are technically called LRC. This search shows several of them available from 2 seconds to 10 seconds.

Thanks Gary! How hard is that to change? I've tested many an alternator at work, but I've never taken one apart.

[Gary Lewis]

Thanks Gary! How hard is that to change? I've tested many an alternator at work, but I've never taken one apart.

It is easy. It goes into the alternator from the back and there are a few small screws holding it in. You pull those screws and pull it out. The brushes will fly but you can put them back in and hold them in place on the regulator with a toothpick.

The new one will have its brushes held with pins and you just put it in, screw it down, and pull the pins.

[Ifitaintbroke]

It is easy. It goes into the alternator from the back and there are a few small screws holding it in. You pull those screws and pull it out. The brushes will fly but you can put them back in and hold them in place on the regulator with a toothpick.

The new one will have its brushes held with pins and you just put it in, screw it down, and pull the pins.

Ok, sounds doable. I'm looking at this one on ebay: https://www.ebay.com/itm/252825717914?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=B5GwTTXlQ5-&sssrc=2349624&ssuid=DHDx0XYjS2u&var=&widget_ver=artemis&media=COPY

The interesting this is that my alternator should have come with one as it is for a v6 mustang/taurus. What I have found with these aftermarket parts is that they are made to very loose specifications. Particularly carburetors. In my parts system at work, the same carb will be listed for a 351w and a 460. Unless I am mistaken, although the carb type would likely be the same, the jet sizing(among other things) would be different for different engines, and there were probably different carburetors for different vehicle options and the same engine. Alternators seem to be the same way. The voltage regulator I currently have is probably just a generic 3g regulator, and I highly doubt if any parts store alternator would have the lrc regulator.

[Gary Lewis]

Ok, sounds doable. I'm looking at this one on ebay: https://www.ebay.com/itm/252825717914?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=B5GwTTXlQ5-&sssrc=2349624&ssuid=DHDx0XYjS2u&var=&widget_ver=artemis&media=COPY

The interesting this is that my alternator should have come with one as it is for a v6 mustang/taurus. What I have found with these aftermarket parts is that they are made to very loose specifications. Particularly carburetors. In my parts system at work, the same carb will be listed for a 351w and a 460. Unless I am mistaken, although the carb type would likely be the same, the jet sizing(among other things) would be different for different engines, and there were probably different carburetors for different vehicle options and the same engine. Alternators seem to be the same way. The voltage regulator I currently have is probably just a generic 3g regulator, and I highly doubt if any parts store alternator would have the lrc regulator.

I think that regulator will help you.

As for what regulator you may have, the note at the bottom of that advert says "F794 without LRC. F795 with LRC". And from what I remember the F795 is white.

Concerning what the LRC regulators came on, my understanding is that they were for the vehicles with little engines because the standard regulators brought the alternator in faster than the ECU could respond when a high-current load was turned on. My 460/7.5L doesn't even flinch when loads come on, but a little 2.0L does.

[Ifitaintbroke]

I think that regulator will help you.

As for what regulator you may have, the note at the bottom of that advert says "F794 without LRC. F795 with LRC". And from what I remember the F795 is white.

Concerning what the LRC regulators came on, my understanding is that they were for the vehicles with little engines because the standard regulators brought the alternator in faster than the ECU could respond when a high-current load was turned on. My 460/7.5L doesn't even flinch when loads come on, but a little 2.0L does.

In other words, the reason we are using the lrc is different. Its because the belt drive cannot handle the sudden load, not the engine. It'd have to be one heck of an alternator to stall a 460.

[Gary Lewis]

In other words, the reason we are using the lrc is different. Its because the belt drive cannot handle the sudden load, not the engine. It'd have to be one heck of an alternator to stall a 460.

Yes, on all counts. The EEC-V system on Big Blue knows when the A/C compressor comes on and is capable of bringing the idle speed up to compensate. But it doesn't have to as you can't tell when the compressor engages.