Alternator swap, keeping it all Toyota.
 

It has been about a month since the swap with no issues to date.



SO, I did more digging around elsewhere, trying to cross-reference other vehicles with the 20R engine to see what might be had... Not much...
But, I did find that the 1980 Land Cruiser, with a 6 cylinder engine, uses an Alternator with an internal regulator - well, it's attached to the case of the alt. that has about the same brackets, so will hook up to the 1980 20R brackets.
However, trying to find one has proven to be difficult as the usual auto parts shops (Advance, O'Reilly's, etc) have them listed in their database, but have none in stock, or they are discontinued. Napa on the other hand HAS them, but usually you have to order them. So I ordered one. They come with the Regulator and plug oriented at 10 o'clock or 2 o'clock, all I could get was one set a 10:00 which I hope will not interfere with the radiator hose, we shall see...
ALSO, the top mount on the old Alt. is set at about 1-2 o'clock, where the Land Cruiser one is at 12 o'clock, so a shorter belt may be necessary to get it tight enough.

I found a write up on another site explaining some Alternator variations and how to wire them;
http://forum.ih8mud.com/threads/volt...-works.784192/

What it looks like though, is I'll be doing a 2-wire setup. Main Batt terminal to Battery + post with a 6 ga wire and fusible link, and a wire from the IG plug terminal on the Alt to the black with yellow stripe wire in the harness that goes through the ignition switch OR I could take the wire straight to the Battery + terminal with its own fusible link. I admit, I'm not sure why it needs to go through the ignition switch... I also plan to put a volt meter in the cab as I never really liked the Ammeter gauge. Voltmeters are much more reactive and show you more of what's going on with the system, IMHO...

I now get 14.45 VDC at the battery.
It does need to be goosed to start charging. I cut into the ignition wire at the plug that connects the original voltage regulator plug. Now for clean up, and I'll do a write up tomorrow...

One thing I need to figure out, even after looking through the forums (too many possibilities) is a fusible link for the alt to batt wire... Just a 55 amp alt using 6ga wire. Not sure what size link to use, or maybe just get a HD fuse holder and put in a ? amp fuse... Could use some suggestions...
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Things needed:
55 amp Alternator from a 1980 Land Cruiser with internal regulator.
New V-belt, 34 1/4" length - no shorter than 34 1/8", but no longer than 35".
Roughly 10' of 6ga battery cable with lugs attached.
A spool of 10ga wire for IG cable.
Car jack.
Butt splices and other connectors for 10ga wire.
Wire cutters/strippers/crimpers.
Multimeter.
General garage tools.

I will assume if you plan to do this you are a 'shade-tree mechanic', so will not do an extreme step by step set of instructions.

First, after assembling all components, secure your vehicle on a flat surface, parking break on, wheels chocked, etc.
Open hood and disconnect the battery cables (both + and -, just for safety).
Remove your original alternator (bolts, v-belt, cables).
Now, when I got the Land Cruiser (hereafter referred to as LC) Alt from Napa, it did not have a pulley on it, so I had to take my old alt and the LC alt and swap the pulley. You may be able to do this yourself, or you can take them to a local store and they will usually do it for you. Now to swap it in.


https://cimg4.ibsrv.net/gimg/www.yot...8e2f301231.jpg



LC Alt on left, Pickup Alt on right


https://cimg7.ibsrv.net/gimg/www.yot...679263b253.jpg


LC Alt top, Pickup Alt bottom

Now, as the LC alt has the regulator and the top mount that bolts onto the adjustment bracket is in a different location, it is difficult to get in. I had to unbolt the drivers side engine mount and jack the engine up a small amount to give me some room. Just don't go nuts and jack it way up or you can damage your lower Radiator hose, among other things.

https://cimg3.ibsrv.net/gimg/www.yot...a47a082fc2.jpg


LC Alt in place. Tight squeeze!

In the above image you see a v-belt on the LC alt pulley, but the top mount is way out. This was the original v-belt. I had to purchase and return several belts to get the right size, which a 34 1/4" belt worked. I have about 1/2" of room for belt stretch.
Now, before you tighten everything up, you need to attach the cables. 6ga cable lug to the + Batt terminal and a female spade connector crimped onto the end of the 10ga wire will attach to the IG input on the back of the LC alt. I could have found a Land Cruiser plug and wired it here, so you have choices to make, however, this worked very well. I then covered them with some wire loom (again, your choice) up to where I spliced into the trucks wiring harness.


https://cimg2.ibsrv.net/gimg/www.yot...174e78cc90.jpg


New battery cable with IG cable at Alt in wire loom

Now, as the alternator is on the drivers side, and the battery is on the passengers side of the engine compartment, you have to run the 6ga cable a long distance. I had the folks at Napa make me up a 10 foot long cable after doing rough measurements. 9 1/2' probably would have worked, but as the cable is sold by the foot, I got 10'. This got run from the LC alt, up to the fender where the original regulator is, back to the firewall, across the firewall to the passenger side fender and to the + battery terminal.


https://cimg9.ibsrv.net/gimg/www.yot...f1c83f8652.jpg


New + battery cable at battery

Back on the alternator side, the 10ga wire that goes from the IG terminal, I spliced it into the original wiring harness. This is the one large red wire out of the original harness/plug.


https://cimg3.ibsrv.net/gimg/www.yot...2a929b2beb.jpg



https://cimg9.ibsrv.net/gimg/www.yot...8d210f4328.jpg

I used a pin and socket plug here, just in case this didn't work right (but it does). Once that was connected, and the LC alt tightened down and everything else put back together, I used cable ties to secure all new wiring, etc.

Now it is time to test if it worked as planned.


https://cimg7.ibsrv.net/gimg/www.yot...537c74cfb8.jpg


Fully charged battery

Here is the multimeter hooked up to the battery, fully charged.
I stared the truck and got it to idle and the reading went down until I goosed the throttle. An audible 'click' came from the LC alt and, voila!


https://cimg1.ibsrv.net/gimg/www.yot...23af7c7042.jpg


With Alt running

We have a running, charging alternator!

Not shown is the Voltmeter I installed, took the + lead off the back of the Ammeter (CAUTION! Ammeter is Always hot!) and ran the - side directly to the battery - terminal. I also hooked into the lighting circuit for the gauge off of the Ammeter light as well.

~FIN~

Good writeup and pics. Glad everything worked out for you, and anyone who follows your lead.

Thank you, I've cleaned it up some since the pictures, like a new - battery cable, and ring terminals on all connections. Now to work on de-smogging it and fixing a vac leak that gives me a rough idle, among other little things.

So with the LC alternator you gained 15 amps?
What was the price on the alternator?

I paid $112 with core return.
Yes, they took the old alternator, even though it was not the same kind as the return core.