alternator for m37

[rtkjmk]

I am in the process of installing new wire harnesses in my M37 , has anyone tried to install a late model military 60 amp alternator ( used on duce 1/2 and 5 tons) in place of the generator ? I can get a civilian 24 volt one wire alternator fairly cheap , but I am leaning towards the military 60 amp . Just something to think about "while I am at it rule " bob k

[Rick C]

I did the military 60 amp in muiine. There is a conversion harness available to do this. Couldn't be simpler and the batteries stay nice and charged.

[cuz]

There are two draw backs to the 60 amp alternator. One is it is just as heavy as the 25 amp generator and two it is extremely expensive. You don't need any adapter harness kit. It's a very simple wire-in you can do yourself.
This info is for the Prestolite AMA-5102UT alternator I used on my M37. (see wiring diagram below)

Remove the old generator, regulator and regulator to generator cable.

Install the alternator in the same mount. If the alternator has a double groove pulley then you'll have to move your single groove pulley to it.

Either remove the regulator to firewall harness plug or cut the wires at it's base.

Splice wire 4 to wire 10. Dead end wires 8 & 9 or remove them all the way back to the amp meter.

Run the power feed (10 or 12 gauge)(wire # 5) from the stud terminal B on the new 60 amp alternator to the starter terminal and fasten it there along with wire 4 & 82.

Run a sense wire (14 or 16 gauge)(wire # 568) from the smaller terminal marked iGN to the master switch or the same place you connected the new volt meter on #27.

I like to ad a ground wire (10 or 12 gauge)(wire # 3) from the terminal or stud marked G or a case bolt to the firewall or block.

Remove the amp meter.

Install a volt meter (the military gauge with the color bands) Connecting it's Plus wire to the instrument power #27 harness. This way the gauge only functions when the master switch is on. Then run a ground wire from the new volt meter to a good ground.

TM 9-2920-225--34 is a good manual to get which covers the overhaul, repair and bench testing of the 60 amp alternators.

I am using a 28 volt 60 amp one wire GM Delco alternator on my M38. Lot simpler, lot lighter and 1/3rd the price of the GI 60 amp alternator.

Wiring D sm.JPG (147.83 KiB) Viewed 4855 times

[rtkjmk]

What about the pulley on the M37 , it uses the old wide fan belt , I did not check the diameter of the old generator shaft , Would that be a problem ? After reading wes's post I am inclined to go with a commercial 24 volt alternator , they are common with heavy equipment ,and a LOT cheaper that a rebuilt military 24 volt alternator and all have internal regulators so a one wire hook up would be pretty easy, bob k

[cuz]

Any auto electric shop can set you up with the correct width and diameter pulley to fit your new one wire Delco alternator.

[MSeriesRebuild]

What about the pulley on the M37 , it uses the old wide fan belt , I did not check the diameter of the old generator shaft , Would that be a problem ? After reading wes's post I am inclined to go with a commercial 24 volt alternator , they are common with heavy equipment ,and a LOT cheaper that a rebuilt military 24 volt alternator and all have internal regulators so a one wire hook up would be pretty easy, bob k

We have installed many 24 volt Delco 10SI alternators into military applications. The original belt pulley fits the shaft with one 2 minute mod, easily set up as a one wire or to be excited when the ignition is turned on; it's a 10 minute job to install it on the original bracket with fore and aft adjustment for perfect belt alignment. These were used on GM vehicles and various other applications for many years, parts and take off units are literally everywhere. Any rebuilder can furnish them to you in any number of set up variations for either 12 or 24 volt applications, replacement parts are at any auto parts retailer or auto electrical shop. This one is hard if not impossible to beat any way you look at it if military originality doesn't matter to you. We have rebuilt untold numbers of them in house years ago, now we have a rebuilder that can built them for less than we can buy parts locally and furnish labor, and they are set up to do just that; so we let them have it and purchase from them.

[rtkjmk]

Every body ,Thanks for the info , I am going to go with the Delco unit that Charles recommends .I am trying to keep my M37 as original as possible , but bring the vehicle into the 21 century a little bit , and you sure can't beat a alternator for keeping the batteries up to snuff , especially as most are not driven that much . It's also fairly easy to return to stock in the future if need be , bob k

[captwa]

Wes...thank you for your usual detailed explanation, and for the diagram on how to connect the wiring for the 60A alternator....I have one that I removed from a M152CDN which will soon be installed on my M37CDN, so after I bench test, according to the manual you suggested, I should be good to go...Wilf

[monkeymissile]

I just bought a Prestolite 60A alternator and will let you all know how the upgrade goes.

[captwa]

how did the install go?...W

[monkeymissile]

how did the install go?...W

it was an easy drop-in since all the mounting holes match. My only problem was that the alternator being bit larger in diameter, hit the oil filler tube before I could slip the fan belt on so I just need to get a slightly longer belt; it needs a new one anyway. Swapping the pulleys was cake too.
Next step is installing the wiring harness......