3G Alternator Conversion Page Upgrade.

[Ford F834]

First, for reference I'm quoting info from this page (Electrical/Gauges) and the Gauge Circuits & Spec's tab, which shows the results of my testing of the gauges and wiring harness, and refers to the ICVR page with discusses my testing of that monstrosity. Some time ago I got tired of doing tests and then losing the results, so have been documenting my testing for posterity.

But then you're talking about using the factory wiring to the cab - the ammeter wiring. No matter what wiring you use, you're always getting voltage "in the cab" if that's where the gauge is.

Depending your definition, yes it could be considered the voltage "in the cab", but it will be measuring the voltage effectively at the battery since the red/orange wire connects essentially to the hot terminal of the starter relay. And, my testing shows that the ammeter Rocketman converted to a voltmeter for me only pulls ~80 ma, so there will effectively be no voltage drop on that wire to the ammeter since there is nothing else on that wire. In other words, it will be reading battery voltage.

Having said that, 80 ma is too much current to be pulling all the time, so I agree that a relay is required. And for that I'm considering placing a relay in/under the dash to switch the ground to the voltmeter. And, I may take the pull-in current from the black/light green wire which is going to the hot side of the ICVR - as you suggested.

So why not just run the wiring the way it needs to be? You have to run 2 wires to the voltmeter no matter what - it's not going to attach to the film circuit. So it's not "another" wire to the voltmeter - it's just one of the 2 that are required. And they don't have to be big - telephone wire is big enough (if anyone remembers what THAT is! ).

I really don't have to run any wires to the voltmeter. As said, the red/orange wire will bring battery voltage right through the film circuit to the voltmeter. And I'll break into the yellow/light green wire in the harness prior to the connector to the cluster and install the relay and ground circuit, so the yellow/light green wire will bring ground to the voltmeter, right through the film. That way there's no change to the cluster itself but installing the voltmeter.

It doesn't matter which side of the voltmeter is switched - every additional connection & switch in the circuit adds resistance. But the ig.sw. is self-cleaning, and built to handle a lot of current. So it's the best switch to turn the voltmeter on. If there's resistance in the stock wiring, fix that. Adding more wiring to bypass problems is just adding more problems.

As said, there's so little current being pulled for the voltmeter that the skinny little red/orange wire won't have enough voltage drop to worry about. And there are no switches nor other wires to go through but the relay and its ground.

There's at least one BIG error in that diagram, so that resistor might be another. Haynes doesn't show it, and I can't imagine why it would be there, in addition to the ICVR. I don't recall my truck having it.

That resistor is there, as you can see on the Gauges page. My DVM registered 8.9 ohms, which is what the all the EVTM's show as well as both the '85 and '86 Wiring Diagrams show at D13 on Page 1.

I'm not sure where you're getting those numbers, but that would mean each gauge averages 5 Ohms, which seems VERY low to me. Especially considering that the fuel sender alone can't go below ~20 Ohms. At 5V, that would limit its max current (even if the gauge had 0 Ohms) to 0.25 Ohms.

Well, my numbers for current draw were off. As you can see from the Gauges page, each gauge pulls about .2 amp, not the 1 amp I was remembering. But the fuel senders run from 10 ohms to 73 ohms, also shown on the Gauges page. And the gauges run about 12 ohms themselves.

My point is: you're in there "fixing" the wiring anyway - why not do it right and fix it all? Don't work around other problems just because they're common & not directly-related to this swap.

I think I am fixing the wiring correctly, but that's my opinion and not everyone will agree with me. I plan to use the factory's hot wire to the gauge and switch the ground with a relay triggered by key'd power. No wires to run through the firewall and nothing to change other than the ammeter to a voltmeter and the ground circuit.

Ok, all of that is really about how I want to put a voltmeter in the system. But now let's turn to the 3G page "upgrades". I've duplicated the existing page and have hidden it in the menu - two ways:

• 3G Alternator Conversion - Tabbed: I'm thinking that there is too much info to put it on one looooong page, so am playing with it in a tabbed format.

• 3G Alternator Conversion - Test: To this point this version is just an edit of the loooong page format.

So, I'd like everyone's input as to which approach seems best - tabbed or loooong paaaaaggggeeee.

I'll work in the background as I can to "upgrade" what is one of our most popular pages on the website. Let's see if we can't make it a bit better.

Gary, I was not able to find the reference regarding the Dodge pulley that some use for 3G conversions to eliminate having to use the spacer. I did find a post on FTE that said it was larger in diameter than the stock pulley and there was some concern that it might not spin fast enough.

What is interesting is that 1992 Ford Econoline vans with the 7.3 IDI came with a 130A 3G alternator and a 2 groove V belt pulley. If you order that alternator it will have the right pulley straight out of the box with no shim or pulley swap needed. Of course, like all convenient parts solutions, this one may be going the way of the dodo. The eBay listing says out of stock, Summit webpage says not available, and RockAuto says only 1 remaining. Other online sellers have it listed, but I don’t know how long this will be an option. I’m almost tempted to buy one just so I have that pulley to put on future units if/when the inventory of ‘92 diesel van alternators dries up. 😔 The manufacturer part number is 7756-3N-2G. This website gives a couple of Ford part numbers for it:

https://www.obbstartersandalternators.com/ford-alternator-7756-f2uu-10300-f2uz-10346-f2uz-10346-f2uu-7756-p-3521.html?gclid=EAIaIQobChMIt4i2mOGr4AIViLfACh0qigUTEAQYASABEgLE6_D_BwE

Here is the image from the out of stock eBay listing:

[85lebaront2]

Gary, I was not able to find the reference regarding the Dodge pulley that some use for 3G conversions to eliminate having to use the spacer. I did find a post on FTE that said it was larger in diameter than the stock pulley and there was some concern that it might not spin fast enough.

What is interesting is that 1992 Ford Econoline vans with the 7.3 IDI came with a 130A 3G alternator and a 2 groove V belt pulley. If you order that alternator it will have the right pulley straight out of the box with no shim or pulley swap needed. Of course, like all convenient parts solutions, this one may be going the way of the dodo. The eBay listing says out of stock, Summit webpage says not available, and RockAuto says only 1 remaining. Other online sellers have it listed, but I don’t know how long this will be an option. I’m almost tempted to buy one just so I have that pulley to put on future units if/when the inventory of ‘92 diesel van alternators dries up. 😔 The manufacturer part number is 7756-3N-2G. This website gives a couple of Ford part numbers for it:

https://www.obbstartersandalternators.com/ford-alternator-7756-f2uu-10300-f2uz-10346-f2uz-10346-f2uu-7756-p-3521.html?gclid=EAIaIQobChMIt4i2mOGr4AIViLfACh0qigUTEAQYASABEgLE6_D_BwE

Here is the image from the out of stock eBay listing:

As far as the spin speed on the upgraded alternators, when I did Darth, I had already mounted the poly-groove belt system and once I did the EFI conversion, I eliminated the unneeded Thermactor pump (it only feeds the catalytic converter on the EFI 7.5L). I had an issue with the pulley that came with the conversion kit being so small the belt would slip on initial start up when the alternator was under a good load. I ended up getting a pulley off a Taurus 3.8L which is about the same OD as the V-belt one on the carbureted 7.5L, no more problems, it didn't actually squeal, just failed easily and left rubber dust all over the alternator.

FWIW, Darth came with a whopping 60 amp 2G for a crew cab DRW truck with 7.5L, and loaded including the trailer package, go figure?

[Gary Lewis]

As far as the spin speed on the upgraded alternators, when I did Darth, I had already mounted the poly-groove belt system and once I did the EFI conversion, I eliminated the unneeded Thermactor pump (it only feeds the catalytic converter on the EFI 7.5L). I had an issue with the pulley that came with the conversion kit being so small the belt would slip on initial start up when the alternator was under a good load. I ended up getting a pulley off a Taurus 3.8L which is about the same OD as the V-belt one on the carbureted 7.5L, no more problems, it didn't actually squeal, just failed easily and left rubber dust all over the alternator.

FWIW, Darth came with a whopping 60 amp 2G for a crew cab DRW truck with 7.5L, and loaded including the trailer package, go figure?

Thanks guys.

Jonathan - Your link is interesting for several reasons. And one of those is the "Clock: 3:00". I was Googling the part numbers we have last night and came across some listings from DB Electrical, more of which later, and found one that says "Clock: 11".

So, see the pics down below, with the 11:00 o'clock pic on the left and the 3:00 o'clock pic on the right. Looks to me like the "clocking" references the position of the plug, and the position of the alternator for that determination is with the pivot ear down and the clamp ear up.

Now for the DB Electric alternators I found:

• F4PU-10346-BA: This is the one that fits Mustangs, T-Birds, and Cougars. Notice that it is only $82.83 with a 1-year warranty and has a 6-GROOVE PULLEY 64mm OD.

• F1DZ-10346-A: Note that this one isn't the other part # we'd found as it ends with "-A" instead of "-B". But it does fit those applications, and then some. And, maybe more importantly, it is a 200A unit, and the description says "Under full load conditions, amperage output at 1200 engine rpm will peak at 200 Amps, amperage output at 600 engine rpm (idle) will peak at 100 Amps." But, it does cost $235.

• F1DZ 10346-B: Then I went directly to DB's site and searched for this alternator, the one that fits the Taurii, Continentals, E & F-Series, etc. And it turns out they have a 130A, 160A, 200A, and 220A for the same application!

So, I'm going to call DB in a bit and see if they can help us/me understand what we should be telling the folks to look for. However, given that the 130A unit is available for ~$83 new w/a warranty, I'm not sure that buying new isn't a good option. Yes, you can hit the salvage and get one for maybe half the price, but in what condition? And what's your time worth?

 

[Steve83]

...the ammeter Rocketman converted to a voltmeter for me...

Aha! Then I suggest mentioning that extra mod on the 3G page, but focusing on the more-common/cheaper/easier/quicker method of installing an aftermarket voltmeter (or '87-04). Then put the full writeup of the modded ammeter & its wiring on your personal build page.

...no switches nor other wires to go through but the relay and its ground.

That's what I meant: a terminal on the wire; to connect to the terminal on the relay; that goes to one of the contacts; going to the other contact; leading back to a relay terminal; mated to another wire terminal. All of those connections will be in your "true battery voltage" circuit. To me, that seems like a lot more work & risk than just finding the 8.9 Ohm resistor, and bypassing it. I might even cut the R/Or wire, and splice it into the Bk/LG on the B+ side of that resistor.

[Gary Lewis]

...the ammeter Rocketman converted to a voltmeter for me...

Aha! Then I suggest mentioning that extra mod on the 3G page, but focusing on the more-common/cheaper/easier/quicker method of installing an aftermarket voltmeter (or '87-04). Then put the full writeup of the modded ammeter & its wiring on your personal build page.

...no switches nor other wires to go through but the relay and its ground.

That's what I meant: a terminal on the wire; to connect to the terminal on the relay; that goes to one of the contacts; going to the other contact; leading back to a relay terminal; mated to another wire terminal. All of those connections will be in your "true battery voltage" circuit. To me, that seems like a lot more work & risk than just finding the 8.9 Ohm resistor, and bypassing it. I might even cut the R/Or wire, and splice it into the Bk/LG on the B+ side of that resistor.

Steve - I'll see how I can incorporate the voltmeter options into the 3G page.

But, I don't think it is wise to remove the 8-9 ohm resistance. (It looks to be a piece of resistance wire as I can't detect any bulges in the run.) I believe it is there to drop the voltage to the flasher/ICVR and thence to the gauges. So unless the user is replacing the ICVR w/a real regulator, removing the resistance will change the average voltage to the gauges and, therefore, change the current, causing the gauges to read incorrectly.

All - I called DB Electric and talked with a really nice lady named Christina. Told her what I'm looking for and she said I need to talk to Hagan, who is in his 70's and really knows this stuff. Since I'm almost 72 we should get along famously but, since he's out today, I'm to call him early Monday.

And, I'd like to brainstorm the questions to ask him. Here's my current thinking:

• Is there a name for the style of mount we need? Or a range of part #'s?

• How much power can the various pulley types transfer? (We should help the reader understand that a single v-belt is limited to something like 90A w/o slipping, and many people who've converted to a 3G have experienced significant belt squeal.)

• If people want to order an alternator with a specific pulley how would we determine the needed part number? And do they have pulleys for two v-belts of the same size. (I'm thinking of Jonathan's recent post.) Is there a way we can create a table with their part #'s and the various pulley styles and sizes?

• What about regulators? Which of their alternators have slow-start or LDR regulators in them? (Slow, or delayed-start regulators bring the alternator in slowly to prevent the belt slippage that Bill spoke of.)

• Is there a disadvantage, other than cost, for the high-output units? Do they put out a higher percentage of their rating at idle than the standard 130 amp units?

So, what questions do y'all have?

 

[ArdWrknTrk]

Steve - I'll see how I can incorporate the voltmeter options into the 3G page.

But, I don't think it is wise to remove the 8-9 ohm resistance. (It looks to be a piece of resistance wire as I can't detect any bulges in the run.) I believe it is there to drop the voltage to the flasher/ICVR and thence to the gauges. So unless the user is replacing the ICVR w/a real regulator, removing the resistance will change the average voltage to the gauges and, therefore, change the current, causing the gauges to read incorrectly.

All - I called DB Electric and talked with a really nice lady named Christina. Told her what I'm looking for and she said I need to talk to Hagan, who is in his 70's and really knows this stuff. Since I'm almost 72 we should get along famously but, since he's out today, I'm to call him early Monday.

And, I'd like to brainstorm the questions to ask him. Here's my current thinking:

• Is there a name for the style of mount we need? Or a range of part #'s?

• How much power can the various pulley types transfer? (We should help the reader understand that a single v-belt is limited to something like 90A w/o slipping, and many people who've converted to a 3G have experienced significant belt squeal.)

• If people want to order an alternator with a specific pulley how would we determine the needed part number? And do they have pulleys for two v-belts of the same size. (I'm thinking of Jonathan's recent post.) Is there a way we can create a table with their part #'s and the various pulley styles and sizes?

• What about regulators? Which of their alternators have slow-start or LDR regulators in them? (Slow, or delayed-start regulators bring the alternator in slowly to prevent the belt slippage that Bill spoke of.)

• Is there a disadvantage, other than cost, for the high-output units? Do they put out a higher percentage of their rating at idle than the standard 130 amp units?

So, what questions do y'all have?

LRC (load response control) regulators were found on Lincoln's and other luxe barges because of things like heated and auto adjusting seats.

I never saw a 3G with a V-belt pulley.

I always called it a pivot mount. With 7 or 8.25" c-c spread.

Other styles include side mount and V-mount.

Belt squeal has always been an issue.

Ok, that's my 2c.

 

[Steve83]

I don't think it is wise to remove the 8-9 ohm resistance.

I don't think it's necessary, but I didn't say to remove it - just bypass it ONLY for the voltmeter feed. It would still be there for the ICVR feed.

...a single v-belt is limited to something like 90A w/o slipping...

It's not that simple. You also have to consider wrap angle & pulley diameter to know how much torque the belt can apply to the alt before it slips.

Do they put out a higher percentage of their rating at idle than the standard 130 amp units?

According to Ford's graphs, there's no appreciable difference.

https://supermotors.net/getfile/1145450/thumbnail/generatoroutput.jpg

There's no reason to install a 95A 3G on anything. As to higher-than-stock-output 3Gs; I just don't trust them enough to risk that kind of money on something that isn't warranted locally. 130A is plenty - especially for a truck originally built to use 70A.

[Gary Lewis]

LRC (load response control) regulators were found on Lincoln's and other luxe barges because of things like heated and auto adjusting seats.

I never saw a 3G with a V-belt pulley.

I always called it a pivot mount. With 7 or 8.25" c-c spread.

Other styles include side mount and V-mount.

Belt squeal has always been an issue.

Ok, that's my 2c.

Jim - Jonathan was just talking this morning about the '92 vans with the 7.3 IDI having a 3G w/a 2-sheave pulley. So apparently they existed but are in short supply. I hope DB says they can do one as I think Jonathan wants one, and it would make things easier for others as well.

Yep, LRC is the right term. I'd forgotten. But, I'll ask Hagan about it on Monday. To me that would be the way to go and I added that to the revised page, although depending on what he says that may need to change. But it seems like it would help w/the belt squeal.

Steve - Yes, the power transfer depends on tension, belt-wrap, etc. So maybe I should edit the page to say that 90 or 100A is the max you can get with the proper belt-wrap, tension, etc. But, let's see what Hagan says about it.

As for more power at idle, not all of the alternators people will be dealing with will be stock Motorcrafts. DB's 200A unit says "Under full load conditions, amperage output at 1200 engine rpm will peak at 200 Amps, amperage output at 600 engine rpm (idle) will peak at 100 Amps". So that's why I'm asking that question - do all of their alternators put out 50% of their rated output at idle? Or is it just the HO ones?

And on the 90/95A unit, I've wondered that as well. I could simplify things by just taking the discussion of them out.

As for the 220A units, the longevity thereof is probably a good question for Hagan.

All - I've got a DRAFT of the revised page that I really, REALLY need you to read and comment on:

• Tabs: No one said boo, so I chose the layout I like - tabs.

• I've put a couple of discussions regarding the 7 or 7.5v choke in red. I think they can be eliminated as the 3G's have a stator connection. So if someone is running a 7v choke s/he can continue to do so. And if they are running a 12v choke they must already have a relay to power it. So, that is not an issue we need to discuss.

• I emphasized that they MUST move the alternator's output to the battery/relay. But does it come across strongly?

• I added a bit about buying new alternators since I think that's a viable approach given the cost for a stock 130A. But I'd like to flesh that out a bit with info from DB.

• I took out the original list of potential donors and added the spreadsheet that I derived from the Interchange page. But, I also noted while perusing the DB catalog that while the Interchange page info ends in '97 or so there are later uses of the same alternators. So, more work needs to be done on that list.

• I took the liberty of explaining what I think is the easiest way to implement the voltmeter. I know Steve disagrees, but it seemed like a good place to explain that. Surely it helps them to see a way of implementing it rather than just saying they need to add a relay. No? And, can you read it?

Please have a read and let me know.

 

[ArdWrknTrk]

Jim - Jonathan was just talking this morning about the '92 vans with the 7.3 IDI having a 3G w/a 2-sheave pulley. So apparently they existed but are in short supply. I hope DB says they can do one as I think Jonathan wants one, and it would make things easier for others as well.

Yep, LRC is the right term. I'd forgotten. But, I'll ask Hagan about it on Monday. To me that would be the way to go and I added that to the revised page, although depending on what he says that may need to change. But it seems like it would help w/the belt squeal.

Steve - Yes, the power transfer depends on tension, belt-wrap, etc. So maybe I should edit the page to say that 90 or 100A is the max you can get with the proper belt-wrap, tension, etc. But, let's see what Hagan says about it.

As for more power at idle, not all of the alternators people will be dealing with will be stock Motorcrafts. DB's 200A unit says "Under full load conditions, amperage output at 1200 engine rpm will peak at 200 Amps, amperage output at 600 engine rpm (idle) will peak at 100 Amps". So that's why I'm asking that question - do all of their alternators put out 50% of their rated output at idle? Or is it just the HO ones?

And on the 90/95A unit, I've wondered that as well. I could simplify things by just taking the discussion of them out.

As for the 220A units, the longevity thereof is probably a good question for Hagan.

All - I've got a DRAFT of the revised page that I really, REALLY need you to read and comment on:

• Tabs: No one said boo, so I chose the layout I like - tabs.

• I've put a couple of discussions regarding the 7 or 7.5v choke in red. I think they can be eliminated as the 3G's have a stator connection. So if someone is running a 7v choke s/he can continue to do so. And if they are running a 12v choke they must already have a relay to power it. So, that is not an issue we need to discuss.

• I emphasized that they MUST move the alternator's output to the battery/relay. But does it come across strongly?

• I added a bit about buying new alternators since I think that's a viable approach given the cost for a stock 130A. But I'd like to flesh that out a bit with info from DB.

• I took out the original list of potential donors and added the spreadsheet that I derived from the Interchange page. But, I also noted while perusing the DB catalog that while the Interchange page info ends in '97 or so there are later uses of the same alternators. So, more work needs to be done on that list.

• I took the liberty of explaining what I think is the easiest way to implement the voltmeter. I know Steve disagrees, but it seemed like a good place to explain that. Surely it helps them to see a way of implementing it rather than just saying they need to add a relay. No? And, can you read it?

Please have a read and let me know.

Gary,

A) I don't think the idi has a pivot mount. Iirc it is a 2 bolt side mounted alternator.

Pulley alignment (belts in plane) seems the most important criteria.

So check the offset, shoulder to belt centerlines before committing to the idi pulley.

Sourcing a crank pulley with two sheaves the same size might be a challenge too.

B) Ryan had graphs of the regular 130 putting out over 65 Amps at engine idle rpm, whatever the pulley ratio caused the alternator to spin. (so more at idle than a 2G was rated for outright, but exactly 1/2)

Good of you to make that distinction, and observation.

C) The "overclocked" alternators should have more robust diodes and heavier copper heatsinks on their rectifier board.

The smaller case of the 95A alternators just doesn't provide enough cooling. (Fan flow and/or heatsink)

I'm aware of the size and pulley width of the Mitsubishi 200+A ambulance alternator.

I doubt any 3G case size unit could do that for long, even if it was chain driven.

[Whisler]

Gary,

A) I don't think the idi has a pivot mount. Iirc it is a 2 bolt side mounted alternator.

Pulley alignment (belts in plane) seems the most important criteria.

So check the offset, shoulder to belt centerlines before committing to the idi pulley.

Sourcing a crank pulley with two sheaves the same size might be a challenge too.

B) Ryan had graphs of the regular 130 putting out over 65 Amps at engine idle rpm, whatever the pulley ratio caused the alternator to spin. (so more at idle than a 2G was rated for outright, but exactly 1/2)

Good of you to make that distinction, and observation.

C) The "overclocked" alternators should have more robust diodes and heavier copper heatsinks on their rectifier board.

The smaller case of the 95A alternators just doesn't provide enough cooling. (Fan flow and/or heatsink)

I'm aware of the size and pulley width of the Mitsubishi 200+A ambulance alternator.

I doubt any 3G case size unit could do that for long, even if it was chain driven.

I have a 130 A 3G alternator on my truck with a single V-belt and so far (fingers crossed) it is not slipping.