How to tell what alternator mount I need?

[jholovacs]

I have a 1982 Universal M-40 marine diesel, and my alternator has blown out. I want to splurge and get a high-output Balmar 120+ amp replacement (pretty sure the alternator blew out the first time I tried to run on my new lithium bank, even though they weren't low), but I don't understand the lingo of the options. It's a specialty part and a lot of money so I don't want to get it wrong. Is there some table I can look this up, or if someone can advise me what I need to look for I'd appreciate it.

Also, I'm just kinda assuming balmar is the way to go, if there's a better, more reliable alternator setup for my lithium banks I'd really appreciate some advice. It's a bunch of money.

[Dsanduril]

There are really two styles of mounts (in the marine world); single spindle foot and saddle mounts. The spindle foot mounts have a single, large foot on the hinge side and commonly come in two versions:1” (“Motorola”) and 2” (“Delco”). The saddle mounts also come in two versions, with 3.15” (“Hitachi”) or 4” (“J180”) between the two hinge feet. The other critical dimension is the distance between the hinge bolt and the locking bolt on the opposite side.

If the online sources are right the M40 uses a 2” Delco mount like this one:
You can confirm by measuring the length of the hinge foot and the distance from hinge to locking bolt.

That’s not to say any alternator with that mounting style will fit, you will have to look at the size of the body (to make sure the engine block doesn’t interfere with mounting) and the type and placement of the pulley.

Defender has a page (maybe from Balmar) with the typical styles.