12v m37

[pwrwagonfire]

My M37 had been converted to 12volt long before I got it. It functions ok, BUT...

The alternator dosent appear to be in exactly the right spot...resulting in MUCH squeeling from the belt whenever I step on the gas pedal. The fan belt is tightened all the way, and I can still move it by hand. Should I explore cutting down the fan to move the alternator foward more?

Could any folks on here with 12volt systems in their M37/varients please post pictures of their alternator set-up?


I appologise for no pictures, but Im an hour away at school till this weekend...

 

[M543A2]

Are the pulleys on the motor and fan still stock? My thought is that the alternator has the normal narrow civilian automotive belt pulley on it. To fit the alternator pulley has someone put a narrow automotive belt on the truck? The truck crank pulley and fan pulley are made for a belt that is about 5/8 inch wide. The narrow belt that fits the alternator will drop so far down in the motor and fan pulleys that it does not wedge in the pulley, but rides on the bottom of the groove. You cannot tighten it enough to make it not slip. Try to get a wider pulley for the alternator so you can use a wider belt.
Regards Marti

 

[pwrwagonfire]

The belt pully's on the fan/motor are still millitary; it looks like you hit the nail right on the head...I checked out the alternator, and it does in fact have a narrow civilian pully.

Thank you very much for your thoughts on this, I appreciate it!


Hopefully this weekend I can get around to fixing it....

 

[M543A2]

A thought from my racing a 440. The alternator belt would walk up out of the pulley grooves at high RPM and, unbelievably, ride on its back on the top edge of one side of all of the pulleys! I tried all sorts of cures, and finally went to NAPA and got a green colored fractional horsepower belt of the right length. I used what is called a "B" width belt. This is wider than the automotive belt, but it still drives the alternator fine even though it does not go clear down into the groove. No more thrown belts! My point is maybe one of these belts would be wide enough to wedge sufficiently in the motor and fan pulleys and still drive the alternator like it does mine.
Regards Marti

 

[SasquatchSanta]

Here are some pics of my M37.

I installed a pully for a wide belt on the alternater.

I'm running an electric (12-volt) fan so I've got a lot of room under the hood.

 

[pwrwagonfire]

A thought from my racing a 440. The alternator belt would walk up out of the pulley grooves at high RPM and, unbelievably, ride on its back on the top edge of one side of all of the pulleys! I tried all sorts of cures, and finally went to NAPA and got a green colored fractional horsepower belt of the right length. I used what is called a "B" width belt. This is wider than the automotive belt, but it still drives the alternator fine even though it does not go clear down into the groove. No more thrown belts! My point is maybe one of these belts would be wide enough to wedge sufficiently in the motor and fan pulleys and still drive the alternator like it does mine.
Regards Marti

Hey thank you, Im going to have to look into that after I get the truck running!

SasquatchSanta: Thank you very much for the pictures...I assume you added a millitary belt pully onto the alternator?



Does anybody know the NAPA part number for the correct belt? The store in my town is kinda....eh. So it would really help alot to be able to go in there with a #...

 

[SasquatchSanta]

pwrwagonfire wrote:

SasquatchSanta: Thank you very much for the pictures...I assume you added a millitary belt pully onto the alternator?

Your welcome and yes indeed I'm using a standard M37 belt. I don't have a NAPA number. The last belt I bought came from John Bizal @ Midwest Military in Prior Lake MN --- 952-440-8778

 

[pwrwagonfire]

Does anybody know of any specs for the 12v alternator? Ive spent the day fighting with getting the belt pully off (got a new wider one from Memphis Equiptment). Finally stopped by CAP to see if it was worth just getting a new one. Turns out upon inspection the brushes on the interior are all worn out...they said re-build it or...

So, I order a new one which LOOKS identical to the one I took out. Now my dad is asking me a ton of questions making me nervous about my purchase. The new alternator will be in tomorrow morning.

Also, Ive heard a little machining will be necessary to get the wider millitary belt pully to fit...in what way? I can see the problem when I put the pully on the shaft, but Im not quite sure the best way to go about attaching them together.

 

[pwrwagonfire]

Just as an update, I DID finally get a new alternator in (after much trouble)

Posted pictures of it in my thread titled "My New Toy."