Instead of breaking my piggy bank for a 140Amp or more alternator, I just went down to the local parts counter and paid $30 for a stock replacement alternator. I left my existing one alone. The A.I.R. pump didn't work anyway, so I took it out and mounted the second alternator there. It runs from the pulley that the air pump used to run on, I just needed a shorter belt. Now if either one fails, I still have a working one. Plus, I can collect the lifetime warranty on either one, since they are the same.
To mount it, I had to space the mounting bracket out 1/2" to make the pulleys line up. I removed the bracket from the block and put two nuts behind it as spacers, using bolts that are 1/2" longer. Then I had to hack off the bottom of the flat bracket that mounts to the bottom of the alternator and to the water pump housing. This is because the alt is about 2" bigger in diameter than the air pump. I cut off the bolt hole that used to hold the air pump in adjustment and drilled out the Battery ground cable hole to hold the adjustment bolt. I reused the stock slotted adjustment bracket from the AIR pump. It had an offset bend in to to recess it, so I bent it out to straight to get the needed 1/2".
For wiring, I put heavy ring terminals on some 10gauge cable and ran it about 2.5 feet from the output terminal to the starter motor. I would have used bigger cable, but this is actually bigger than what is currently running to the 1st alternator (maybe I should upgrade that sometime soon?) Then I used a new alternator connector and spliced into the existing alternator's two wires so that they are both wired the same.
Granted, they will never share the load evenly, but as long as there is enough demand to get one up to it's max output (for that engine speed), the voltage will dip enough for the other one to charge. With a really heavy load, the voltage will be low enough for both to give max output.
The only bad thing so far is that the pulley for the 2nd alternator is smaller then the other two pulleys on the water pump, so the 2nd alt spins slower. This is counter-productive to my goal of getting more current at idle, but it does still charge some at idle with the 1st alternator disconnected. If I ever find a cheap water pump pulley that has 3 of the larger size grooves, I will swap that on.
So I put about $50 into the whole thing. I'll get $15 back if I ever come up with a core to return.
To mount it, I had to space the mounting bracket out 1/2" to make the pulleys line up. I removed the bracket from the block and put two nuts behind it as spacers, using bolts that are 1/2" longer. Then I had to hack off the bottom of the flat bracket that mounts to the bottom of the alternator and to the water pump housing. This is because the alt is about 2" bigger in diameter than the air pump. I cut off the bolt hole that used to hold the air pump in adjustment and drilled out the Battery ground cable hole to hold the adjustment bolt. I reused the stock slotted adjustment bracket from the AIR pump. It had an offset bend in to to recess it, so I bent it out to straight to get the needed 1/2".
For wiring, I put heavy ring terminals on some 10gauge cable and ran it about 2.5 feet from the output terminal to the starter motor. I would have used bigger cable, but this is actually bigger than what is currently running to the 1st alternator (maybe I should upgrade that sometime soon?) Then I used a new alternator connector and spliced into the existing alternator's two wires so that they are both wired the same.
Granted, they will never share the load evenly, but as long as there is enough demand to get one up to it's max output (for that engine speed), the voltage will dip enough for the other one to charge. With a really heavy load, the voltage will be low enough for both to give max output.
The only bad thing so far is that the pulley for the 2nd alternator is smaller then the other two pulleys on the water pump, so the 2nd alt spins slower. This is counter-productive to my goal of getting more current at idle, but it does still charge some at idle with the 1st alternator disconnected. If I ever find a cheap water pump pulley that has 3 of the larger size grooves, I will swap that on.
So I put about $50 into the whole thing. I'll get $15 back if I ever come up with a core to return.
