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Putting a HMMWV 400 AMP alternator on a Cummins NHC250. Has anyone done it? Need info

goldneagle

goldneagle

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Suprfknman said:
60 amps doesn't seem like much for such a big truck granted its 24v so i think that would be equivalent to a 120 amp 12v alternator.
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Does not matter. We are discussing installing a 400 AMP alternator in it's place. Only reasons are: It's dual voltage, the price was great. Could not find the 200 AMP version at a reasonable price. Did not realize it was that big. Was told it would fit. Wanted a way to charge up the 12 volt battery bank in the camper.
 
Cycletek

Cycletek

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Bracketry is a small part of the problem, the coolant filter canister cap has a rear exit that drops behind the Alternator. It makes it difficult to put in a longer Alternator, not impossible. The cap needs to be spaced out so it is further out to allow the longer unit to fit. A couple of slightly shorter belts will tuck the unit a bit closer to the block, there is about 5 inches of room there. On the 900 series with the trans cooler there is 4 inches of room to move out the cap, on my 800 series there is 7 inches before interference with inner fender sheet metal since I do not have the Allison Trans......
 
goldneagle

goldneagle

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Cycletek said:
Bracketry is a small part of the problem, the coolant filter canister cap has a rear exit that drops behind the Alternator. It makes it difficult to put in a longer Alternator, not impossible. The cap needs to be spaced out so it is further out to allow the longer unit to fit. A couple of slightly shorter belts will tuck the unit a bit closer to the block, there is about 5 inches of room there. On the 900 series with the trans cooler there is 4 inches of room to move out the cap, on my 800 series there is 7 inches before interference with inner fender sheet metal since I do not have the Allison Trans......
Click to expand...
Just to clarify the part names I looked them up in the TM. I did not think the engine had a built-in coolant filter. According to the TM the part you are referring to is an engine oil cooler #4 on the drawing. I am attaching the scanned image of the page to make it easier to identify.

M923_Cooling.jpg
 
Stalwart

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Sephirothq said:
Just to throw this out there. I think that is a one way pulley on the alternator. So you have to have to have it turning the proper direction. Also you will need a serpentine belt instead of the v belt system. I also remembering hearing the reason they put the one way pulley on there was to protect the alternator in case the engine turned backward or else the regulator gets burned up.
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Alternators don't care which direction they are turned, it is only the cooling fan that is really directional.
 
Cycletek

Cycletek

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goldneagle said:
Just to clarify the part names I looked them up in the TM. I did not think the engine had a built-in coolant filter. According to the TM the part you are referring to is an engine oil cooler #4 on the drawing. I am attaching the scanned image of the page to make it easier to identify.

View attachment 417987
Click to expand...
Number 4 needs to be spaced out........I stand corrected, I am going to see if I can get these pieces on Monday so I can fab up a spacer
 
Last edited:
goldneagle

goldneagle

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Stalwart said:
Alternators don't care which direction they are turned, it is only the cooling fan that is really directional.
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As long as both engines rotate in the same direction we should be good there. Main issue is getting the cooling system components out of the way.
 
goldneagle

goldneagle

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Cycletek said:
Number 4 needs to be spaced out........I stand corrected, I am going to see if I can get these pieces on Monday so I can fab up a spacer
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I found an interesting picture of the entire housing that I am attaching.

$(KGrHqJ,!iwE6G3zO-H,BOihS4hUs!~~_3.jpg

There is a brand new #4 available on an internet popular site.
 
NDT

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goldneagle said:
Does not matter. We are discussing installing a 400 AMP alternator in it's place. Only reasons are: It's dual voltage, the price was great. Could not find the 200 AMP version at a reasonable price. Did not realize it was that big. Was told it would fit. Wanted a way to charge up the 12 volt battery bank in the camper.
Click to expand...
What 12 volt amps does it produce?
 
Vintage iron

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WOW! that is a great price! I will need to check them out. I have done some measurements too. Yeah it will be a tight fit trying to put that mammoth 400 amp alternator on a M923. I think that a 250 amp alt. will be a easier fit. I am going to recommend my customer goes with the PTO driven generator I have that runs off an Allison transmission.
 
goldneagle

goldneagle

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Vintage iron said:
WOW! that is a great price! I will need to check them out. I have done some measurements too. Yeah it will be a tight fit trying to put that mammoth 400 amp alternator on a M923. I think that a 250 amp alt. will be a easier fit. I am going to recommend my customer goes with the PTO driven generator I have that runs off an Allison transmission.
Click to expand...
The difference is that I can charge the battery bank while driving. Whereas the PTO driven generator will need to run when the truck is parked. I can still charge the battery bank while parked as well.
 
goldneagle

goldneagle

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NDT said:
Might be 5 amps 12 volt too. It is only designed to power the 4L80E trans controller.
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Found the following info in a document on the internet: "ALTERNATOR (400 AMPERE) – Is rated at 28 volts at 400 amperes and 14 volts at 50 amperes with external regulator. The alternator assists and recharges the vehicle batteries during operation."
 
Suprman

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I have seen 5tons with big radio racks between the drivers and passenger seats I wonder if there is a higher current alternator made for the 939s
 
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