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How to: Alternator upgrade - 4G, 3G large or small case?

2000StreetRod

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Since I have much of the engine torn apart to start installing my Banshee M90 supercharger kit I decided to upgrade my alternator and associated wiring. According to my internet research I think my stock alternator is either a T mount 4G or 3G with a small or large case.
StockBack.jpg

StockFront.jpg

StockTop.jpg

I've searched various suppliers' online adds that have supposedly direct replacements for my alternator but they seem to vary in size and configuration of the terminals. I would like to purchase a 200 amp alternator that is not any larger in diameter than my existing one with the positive terminal on the rear. That will give me the most clearance for my main intake tube.

Does anyone know for sure which case I currently have? It has Motorcraft showing on the rear of the case.

I was considering a Powermaster 200 amp alternator but can't determine which one is the same size as the one on my 2000 Sport with the SOHC V6. I sure could use some help because I don't want to order the wrong one.
 

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2000StreetRod

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I agree it's a 4G

Thanks for your response and the link to the helpful website. I agree that mine looks like a 4G which means the Powermaster 47787 should be a suitable 200 amp replacement. Summit Racing sells them for $377.
47787.jpg

I searched the internet and was unable to find a photo of the alternator rear showing the charge terminal. From the front view angle I can't determine if it's a top terminal.
 
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2000StreetRod

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Charge cable size & routing

Powermaster provides the following guidance for charge cable size for 175 to 200 amp alternators:

#4 up to 7 feet, #2 for 7 to 13 feet, #0 for 13 to 16 feet

My 1975 Electronics Engineer's Handbook states: for AWG 2 copper the max current for single wire is 181 amps and 100 amps bundled; and for AWG 0 copper the max current for single wire is 245 amps single wire and 150 amps bundled.

I think AWG 0 would be the best choice if it will fit. I plan to replace the existing charge wire with the #0 cable and follow the same routing: aft of the thermostat housing then diagonally downward in front of driver side head and block into a large wiring bundle. There's only about 5/8 inch clearance between the front of the head and the cast accessory mount that bolts to it.
StockChargeWire.jpg

According to my manual AWG 1/0 has a conductor diameter of 324.9 mils or 8.252 mm leaving 0.3 inches for insulation in the 5/8 (0.625) inch space. I found one listed as having an outside diameter (with PVC insulation) of 0.560 inches which would fit.

My electrical wiring diagram for the charging system shows the output of the alternator going to one side of a 175 amp mega fuse attached to the battery junction box.
BJBMaxiFuse.jpg

A large cable connects the other side of the mega fuse to the battery. Most forum members run a cable from their high output alternator directly to the battery and some install an inline fuse to protect the alternator. I will replace the existing 175 amp mega fuse with a 250 amp fuse.
!BUf3)l!B2k~$(KGrHgoOKjEEjlLmZ(ZQBKN1EHhko!~~_12.jpg


The above will require more wiring harness rework but will avoid another cable to the battery. Also, I've always thought the harness in the area of the driver side motor mount was poorly done and the wire to my added oil pressure sensor is too short.
 
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2000StreetRod

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DB Electrical?

DB Electrical advertises a 200 amp alternator Item Number: HO-7787-200 for $241 that appears to be the exact configuration as my stock Motorcraft.
7786.jpg

7786_back.jpg

7786_side.jpg

One of my concerns is the ebay photos are labeled 7786 so the photos may not be accurate. The other concern is the same I had for the stock alternator which is the height/clearance of the B+ terminal.

Does anyone have experience with DB Electrical alternators?
 
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2000StreetRod

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Alternator/battery/starter wiring harness removal

Listed below are the steps I performed to remove the wiring harness that connects the alternator charge cable to the battery junction box, battery and starter.

1. Disconnect battery terminals.

2. Disconnect alternator B+ terminal identified by red arrow below.
Altntr.jpg

3. Disconnect alternator charge cable support bracket identified by blue arrow above.

4. Disconnect A/C compressor clutch connector.

5. Remove cast accessory (A/C compressor & PS Pump) support.

6. Remove charge cable protector mounting bolt (use 8mm socket).
Protector.jpg


7. Disconnect oil pressure switch connector (squeeze).

8. Disconnect motor mount wiring harness bracket retainer bolt (use 10mm open end or box wrench while working under vehicle).
LoomMntU.jpg


9. Separate wire loom from fastener. I cut the tape to avoid breaking the plastic fastener.
LoomMnt.jpg


10. Disconnect shock mount wiring harness bracket retainer bolt (use 10mm socket).
ShockLoom.jpg


11. Disconnect starter relay ground lug bolt (use 13mm socket).

12. Pull away plastic protector for starter motor terminals.

13. Disconnect starter motor energizer terminal (use 10mm socket).

14. Disconnect starter motor positive supply terminal (use 13mm socket).

15. Separate wire loom from fastener below 4WABS.

16. Remove mega fuse retaining nuts (use 13mm socket) being careful to support terminals while loosening nuts.

17. Disconnect 4WABS connector.

18. Disconnect battery ground terminal to chassis lugnut (use 11mm socket).

19. Carefully remove wiring harness.

ChargeHarness.jpg
 
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Anime

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The alternators that DB Electrical sells appear to just be the $100 made in China aftermarket 130A units, that are taken apart and put back together with slightly better hardware to push 200A out of them.

Not that that's bad, it might be the standard of the industry at the moment, or is just how they do business on a mass scale.

Personally I'd suggest sticking with a 130A stocker (or going to an aftermarket 130A if yours is on it's way out or you just want a new one), unless you NEED 200 amps of power for an array of audio amplifiers or something. An alternator that puts out more power puts more drag on the engine to do it, and it's just a waste of horsepower and money if you put a 200A alternator on there for $241 but you'll never use the 70 extra amps for anything.
 
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2000StreetRod

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upgraded rectifiers

Thanks for the reply Anime. I was wondering if they might just be the stock type units with upgraded rectifiers and a smaller pulley to spin faster. I could have that done to my stock unit at a local shop.

I agree that the 130 amp capacity is adequate for the stock vehicle accessories. And I have no intentions or interest in light racks or obnoxious audio. However, my high flow fuel pump draws extra current and I will be adding an intercooler pump. Eventually I may install an electric motor driven radiator cooling fan, water pump and power steering pump.
 
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2000StreetRod

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two sources physically same as stock

Powermaster never responded to my email questions so I did more research. I found their application guide and confirmed that the 4G is the family for the 1997 to 2006 Explorer with the 4.0L OHC. The Powermaster part number for the 200 amp max/125 [email protected] engine rpm alternator is 47787 for the natural finish and 57787 for the black finish. I noticed when reworking the engine wiring harness that there are only two wires connected to the internal voltage regulator. The wiring diagrams show a third wire with a note that I can't decipher but may mean applies only to 4.0L OHV. I downloaded the Powermaster catalog and found the dimensions of the 47787. The case diameter is 5.9 inches and the distance from the front of the pulley to the rear of the case including the terminals is 5.18 inches. The terminal configuration appears to be the same as stock. So now I assume I have two sources for a 200 amp alternator with the same physical configuration as my stock alternator. Therefore, I will follow my original plan to perform the wiring harness upgrade now but defer the alternator upgrade.
 
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Anime

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2000StreetRod

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remanufactured instead of new

I noticed some 4G 200A alternators on ebay were only ~$150...but they are for the 02-05's with the 4.6L V8. The price difference just for the mounting points is interesting. . .

Part of the reason for the price difference is that one is remanufactured instead of all new. I could possibly purchase that one and then install the contents in my stock case but then it wouldn't be warranted. I went to their online store and found a 200 amp 3G style that according to them was used on the 2004 and 2005 Explorer: FORD EXPLORE Mercury Mountaineer 4.0L 200 HIGH AMP NEW ALTERNATOR 06 07 08
200Amp04to07.jpg

According to the Powermaster application guide the 2004 and 2005 uses a 4G style. According to the Powermaster catalog the large 3G case diameter is 5.90 inches and the front of the pulley to the rear of the case (including the terminals) is 6.25 inches. Since I have to route the upper radiator hose between the rear of the alternator and the valve cover I have to stay with the shallower 4G case (5.18 inches).

I searched their online store more and found a 4G 220 amp for $170 that is the same configuration as my stock unit: NEW FORD EXPLORER 5.0L 96 97 98 99 00 01 OHC 4.0L HIGH AMP ALTERNATOR 4G Series
220Amp4G.jpg

It specifies using the I-S-A regulator which matches my wiring diagram unlike others that specify the I-D-A regulator.

Thanks for posting the link Anime. It may have prevented me from buying a noncompatible alternator and allowed me to find a higher capacity one for less money.
 
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2000StreetRod

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charge cable

I finally obtained an alternator positive terminal boot suitable for the 1/0 gauge charge cable from the alternator to the Mega Fuse mounted at the battery junction box. It's part number BOOT4REDST from C E Auto Electric Supply. I tried the one advertised for 1/0 gauge but it was too long and too loose. This one for 4 gauge takes a little effort to install on the cable but fits fine.
ChargeCbl1.jpg

I'll install a loom on the exposed sections for additional protection. I reworked the cable support to keep the cable low in hopes of having clearance for my custom intake for the M90 supercharger.

There is just enough room between the accessory casting and the head for the cable to fit with no room for a loom.
ChargeCbl2.jpg


The cable has to be routed down thru the notch in the casting or it will crimp the cable insulation.
ChargeCbl3.jpg


The cable supports will have to be opened up to allow room for the larger loom required to house the larger charge cable with the rest of the wires.
ChargeCbl4.jpg

My 1/0 cable measures 0.625 inches in diameter. The largest loom I could purchase at local auto parts stores was 3/4" dia. I'll probably have two looms for the wiring harness near the battery junction box since there will be two 1/0 cables there.
 
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2000StreetRod

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Mega fuse connections

I cut the charge cable to a 58" length (not including terminals) but it ended up having slightly less slack than I wanted so 60" would be a better length. I used a propane torch to solder straight copper terminals on each end of the cable since I couldn't find any right angle terminals.
FuseCnx3.jpg


I decided to modify and reuse the stock Mega fuse right angle terminal.
FuseCnx1.jpg


I used a hack saw to cut the terminal just prior to the neck.
FuseCnx2.jpg

Then I drilled a 1/4" dia hole in the right angle Mega fuse terminal to attach the charge cable terminal using M6-1.0 hardware.
FuseCnx4.jpg


I found that bending the terminals to the Mega fuse eliminated the strain on the flimsy mount while reducing interference with the nearby brake lines.
FuseCnx5.jpg


Below is the final configuration after installing looms.
FuseCnx6.jpg
 
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jd4242

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DB Electrical advertises a 200 amp alternator Item Number: HO-7787-200 for $241 that appears to be the exact configuration as my stock Motorcraft.
View attachment 75246
View attachment 75247
View attachment 75248
One of my concerns is the ebay photos are labeled 7786 so the photos may not be accurate. The other concern is the same I had for the stock alternator which is the height/clearance of the B+ terminal.

Does anyone have experience with DB Electrical alternators?

Db is crap.I purchased a 200amp unit from them, year or two later it blew.I took it to my local shop to see what was wrong and if it could be fixed.he took one look at it and said there is no way its 200amp.I asked why, he said for starters it was in a stock 90 amp case, pulled it apart and confirmed it was just a cheap China made unit.he said it would be very hard to even fit everything in a 90amp ohv case.I purchased a junk yard 130 amp unit from a 97 and had him rebuild it.puts out little over 215 and cost around a dollar a amp.think I paid $220ish for it.
 
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2000StreetRod

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made in China

Db is crap.I purchased a 200amp unit from them, year or two later it blew.I took it to my local shop to see what was wrong and if it could be fixed.he took one look at it and said there is no way its 200amp.I asked why, he said for starters it was in a stock 90 amp case, pulled it apart and confirmed it was just a cheap China made unit.he said it would be very hard to even fit everything in a 90amp ohv case.I purchased a junk yard 130 amp unit from a 97 and had him rebuild it.puts out little over 215 and cost around a dollar a amp.think I paid $220ish for it.

Thanks for the comments. Yesterday I asked Eagle Auto Electric (another ebay seller) what country their case was manufactured in and where was it assembled. I haven't received a response yet so I suspect the answer is China for both questions. From what I've read about upgraded 4G alternators the least reliable component is the internal voltage regulator. I think I'll follow your example and call local rebuilders about upgrades. It will probably be another month before I need a functional alternator.

EDIT: I received the following response from Eagle Auto Electric: "this alternator is aftermarket, some parts are made in Brazil, some are made in US, assembled in our shop (California), upgraded to high amp, this alternator is 4G not 3G".

EDIT2: I called the best known local alternator rebuild shop manager in Greenville and was told he had no upgrade kits available for my 4G. Their supplier in Georgia closed.

EDIT3: I took a chance and ordered the 220 amp alternator from Eagle Auto Electric for $170 with free shipping and handling since it was a clearance item.
 
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2000StreetRod

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charge & starter cable looms

I finished the charge and starter cables except at the battery.
ChargeCbl5.jpg

I opened up the support bracket loops enough to accept 3/4" dia. looms. The starter to battery wires are in the loom on the left in the photo and the alternator charge cable is in the one on the right. The starter solenoid activater and the oil pressure switch wires are in the small loom shown in the bottom right of the photo and cross over into the large loom on the left. Between the two large looms is the small diameter hose that encases the single wire to my added oil pressure sensor.
 
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2000StreetRod

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Lessons learned

After 1 1/2 hours of fruitless frustration I have determined:

1. The power steering pump is impossible to install in the cast aluminum housing with the pulley installed even though it came out of the casting that way due to the low pressure hose fitting. After a while I remembered that the same thing happened when I replaced the camshaft cassettes. Tomorrow I'll remove the pulley and try again.

2. Due to the bulk of the 1/0 charge cable and using cable ties to attach it to the support brackets the support casting must be removed to install the A/C compressor onto the two long guide studs.
 
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2000StreetRod

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power steering pump installed

Today I removed the power steering pump pulley from the pump and was able to install the pump into the support casting (still wasn't easy). Then I bolted in the support bracket, pump, pulley, and A/C compressor. I didn't bolt in the power steering reservoir because it has to be out of the way to install the new fuel block and fuel supply hose.
FuelBlock.jpg
 
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2000StreetRod

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Battery connections

A 220 amp alternator, charge cable, and mega-fuse to batter cable won't be fully utilized unless there is a comparable capacity battery to ground cable. The stock short ground cable has a very limited capacity of probably 50 amps.
GroundCbl1.jpg

Due to convenience I decided to reuse it but cut off the battery terminal leaving as much cable length as possible.
The stock long ground cable to the starter motor (grounded to the chassis) is larger in diameter with a capacity of probably 100 amps.
GroundCbl2.jpg

Again, for convenience I decided to reuse it. I don't know if the V8 has the same diameter cables going to the starter. If so, I would be concerned about adequate capacity and would upgrade the positive cable. I think the positive cable diameter is adequate for the SOHC V6 with the stock displacement and compression ratio.

I soldered a terminal onto a short section of 1/0 for a ground cable.
GroundCbl3.jpg

I purchased a positive and negative battery terminal with a 1/0, a AWG 4 and two AWG 8 connections. The AWG 4 connections are for the starter motor cables. One AWG 8 connection is reserved for a radiator electric cooling fan. So the other AWG 8 connection will be used for the stock short chassis ground.

I used the bolt identified below for the 1/0 ground terminal.
GroundCbl4.jpg

It's one of the bolts that attach the fuel vapor management valve bracket.
GroundCbl5.jpg

Before removing the bolt I installed a nut on the other bolt to keep the fuel mangement valve bracket from falling.
GroundCbl6.jpg

Then I used a 2 inch diameter wire brush wheel to remove the paint down to bare metal.
 
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