Alternator question (2 Viewers)

[skhawley]

I just replaced the OEM alternator with one from the local Auto-zone, and i have 2 questions about it. One, what is the old amperage on the OEM i think i read that it was a 50 amp alt. My new alt is 80 amps, i was going to swap it out with a 94 4 runner, as i herd that they are a drop in for the 62 and are 80amps as well. Next what is the Capacitor for on an alt and should i keep the old one. Its bigger but i don't know if it holds more of a charge. I took it off the old alt before i got my core deposit back, so if i don't need it i guess I'll hook it up to the door bell or something. Any info on this would be great. I'm new to wrenching and new to the FJ62

 

[Spook50]

The 62's alternator is an 80 amp in stock configuration. Usually when one of these goes out it's just the voltage regulator (which is internal). Problem with the 62's alt is that the VR is soldered in place so it's kind of a PITA to replace. It can be done but you've got to know what you're doing and have at least rudimentary soldering skills.

For a time Beck/Arnley made a 120A bolt-in replacement for the 62 alt. I have one. They came with a junky Chinese voltage regulator inside though that only lasted a matter of months. I did a bunch of digging and found a part number for a legitimate Denso regulator to replace the Chinese crap with, and it's worked great ever since.

My only complaint though is that at idle it doesn't put out the full 14VDC charge, and if you've got headlights, stereo, blinkers etc. running when stopped in traffic you can really see the voltmeter fluctuate. I'm still trying to find a smaller pulley to put on the alternator so that it puts out a better idle charge. Our engines run slow enough that after figuring the RPM of the alternator itself (1.7x the RPM of the engine), even putting on a smaller pulley won't bring it anywhere close to the typical maximum alternator speed where wear is accelerated (about 16,000 RPM, give or take a couple hundred, where a 2.5" pulley would put it at 11,040 RPM at the engine's redline of 4600 RPM). Still haven't had any luck finding one though, so I might just get an OEM pulley and have it milled down to size.

Anyway, the capacitor you're looking at is commonly referred to as a condenser when used the way it is in this case. It basically just suppresses RF interference that can be caused by the alternator which could otherwise manifest as a buzzing in the radio or in extreme cases booger up other electronics in the vehicle. Their physical size shouldn't make any difference. As long as the capacitance is equal, which it should be, it'll be just fine.

Keep the receipt for your new alternator because unless it's actually a Denso unit, you could end up having to swap it out again in the not far future.

 

[Wile E Coyote]

X2 on the potential short life of the new alt. Don't be surprised if it's dead within about a year...no joke.

 

[skhawley]

Thanks for the intel I i will keep an eye on it and see what happens.