Ok do alternators need air to operate? I heard something about air and alternators and can not remember what it was exactly about. Here is the deal. The stupid ass designer of the Xterra decided to put the alternator on the bottom of the engine so I can't go through a mud puddle without blowing it up. Anyway so I was thinking about sealing it up. Good idea or bad idea?

blackX,
Bad idea. They need air to cool them down. Most alternators/generators have a fan type contraption built into the pulley to move air through there...
Bogatyr

I'm thinking it has holes for heat dispersion/ cooling, and would only assume if you blocked the flow of air that it would generate more heat and paossibly seize up.

Indeed, they are air-cooled. There are some water-cooled alternators out there. Cadillac Northstar engines, many BMWs, and Mercedes diesels have them, but none can be adapted to fit an Xterra since they're partially integrated into the block. The reason they use them is because without the cooling fan they are considerably quieter and better suited to ultra-quiet luxury vehicles.
Hitachi makes one that looks like it would work for the X, same type of mount etc, but as I understand it is for industrial applications and considerably larger than ours. The photos I've see have nothing to use for scale, but I called them up last year to ask about it.

Brent

ok so here is an idea. What if you were to seal the alternator up and put a tube on the top and one on the bottom bring them up to the top of the engine, install some sort of fan to make the air circulate through the tubes (computer fans). What about that idea? Do you think it would be possible to do. Well I mean it is possible to do would it be smart? Just trying to figure out how to have fun.

That wouldn't work so well, and could end up costing a lot of money to get it right. Alternators (like all wound motors) need air flow all around them.

It's much easier, and cheaper just to stay out of muddy water 2 feet deep. Water itself won't hurt it, and mud will have trouble getting in it, but muddy water, when forced into it (ie. driving too fast through puddles) will cause problems.

I don't see the costs being too high. Sheet metal bent into a box or sircular form. some foam for around the power cable so you don't have fireworks under your hood. Some rubber gromets for the power wires so you have a nice fit and sealed compartment. Also a gromet to go around the front of the pully axle shaft. You could use some PVC pipe to make the fittings at the box and either tubing of some sort or PVC pipe to bring it to the top of the enging. Mount a 2" fan in the middle somewhere runs some wires and put some sort of filter on the end of the pipes so you don't get crap in there that would not want. It is an experiment but hey it would be well worth it. I am just trying to figure out if it would be a good idea to do before I do it and ask my buds to help out?

Alright, you go right ahead and guinea-pig it for us and get back to us with the results.

Brent

Ya beat me to it, I would love to see the results