Belt squeals when electric fans turn on??? WTH

[Mrturner1]

Originally Posted by elf w/capital T

how did you mount that fan shroud??

I used these but the ones I got are thicker and more rigid. 3 on top and 3 on bottom. These fans came with other hardware but it was for a bigger radiator. I wanted the biggest shroud (covering most surface) I could get, so I got this setup and used the push-thru plastic things in the pic

[davepl]

Difference with cars is the amount of amperage we run through our citcuits. Let's say that it takes 1200W to run those fans.

In a house, where you have 120V, you need 10A. That's a lot of amperage, but well within the range of one outlet.

In a car, we only have 12V. That means you need ONE HUNDRED AMPS of current to get 1200W. That's why the wiring is so important - not because we have high voltage that is going to jump and arc everywhere, but because we're asking our wiring to carry a HUGE amperage load.

Consider that most HOMES have 200A service in total, and your fans want half of that. There's no voltage behind it, but that doesn't matter to the wiring, it only cares about amperage. That's why the wires that feed your entire house are about the same size as your truck's starter cable - similar amp range.

I prefer to crimp and solder everything. Takes time and practice, like everything else.

Mr. Turner is starting from nowhere and has bit off some pretty big projects. I remember what my first forays into car repair looked like, so be gentle! He's not doing everything "right" yet but no one did their first times out, and he's good about taking advice.

[Mrturner1]

Originally Posted by hamjet

Do you have the fans going through a relay first? That will stop it...

I meant no sarcasm by my response, just making sure you knew that I actually was wondering if the black box was a relay lol

[Mrturner1]

Ok so I'm taking the alt to get tested at Napa Auto. I noticed when I was removing the wire on the back of the alt, the threaded stud that goes into the alternator wiggles. I was unthreading the nut that holds the eye on the end of the power wire and the stud just started wiggling, not sure if that's normal.

The wire to the eye that goes on back of the alt is shot, and has the wire but going to the rectangle plug on top of the alt. I guess I'll cut the wire a few inches back from the eyelet and put a new one on, and find out from the test if the alt is still good.

[Mrturner1]

This is the stud that is wiggling around a bit

[Mrturner1]

Well, there's a first time for everything. The guy that sold me the alternator on this site said it was 120amp, but I just had it tested at shop and it's just over 60amps. It's charging right and works great, it's just half the amperage he told me it was.

The guy said he can rebuild this unit for about 100 bucks. That includes a 120amp guts, and a high amperage rotor/stator. I might go that route because it's chrome and matches my other accessories (don't tell GrumpyOldMan I wanna keepin it chrome! lol) but I'm also going to shop around a bit and see what's out there.

What a bummer, guess the guy really wanted to get top dollar for this alternator

[dazza]

Where does the white wire go?

[dazza]

http://madelectrical.com/electricaltech/delcoremy.shtml

This page has a lot of great alt info, including:

Clock position of the SI series of alternators is determined by viewing the alternator from the rear, with the threaded mounting hole straight up. With this view, the receptacle for the two wire plug-in connector will point to any one of the four available “CLOCK” positions. Straight up is 12:00, to the right is 3:00, straight down is 6:00, and to the left as shown in the above photo is 9:00.

[franken]

The amp load on the alt is causing the RPM drop and belt squeal. Dodgy wiring will add resistance to the circuit, which reduces current and therefore reduces load on the alternator. From the pic in post #29, your wiring is dodgy. Fixing the wiring could actually make the problem worse since letting the fans draw more current will load the alt more.
If the harness is pretty stock, you might look into new engine harnesses. They aren't too much money.
I'd be checking for hot spots in the existing wiring when the fans are on, as well as how they're wired. Maybe run them off relays fed closer to the battery, which can provide far more current than the alternator.

[Mrturner1]

Originally Posted by dazza

Where does the white wire go?

The white wire goes to the fuse box in the cab. I'll go double check exactly where it goes and get back to ya. Thanks for the help

Where does the second wire typically go?

[Mrturner1]

Originally Posted by davepl

Difference with cars is the amount of amperage we run through our citcuits. Let's say that it takes 1200W to run those fans.

In a house, where you have 120V, you need 10A. That's a lot of amperage, but well within the range of one outlet.

In a car, we only have 12V. That means you need ONE HUNDRED AMPS of current to get 1200W. That's why the wiring is so important - not because we have high voltage that is going to jump and arc everywhere, but because we're asking our wiring to carry a HUGE amperage load.

Consider that most HOMES have 200A service in total, and your fans want half of that. There's no voltage behind it, but that doesn't matter to the wiring, it only cares about amperage. That's why the wires that feed your entire house are about the same size as your truck's starter cable - similar amp range.

I prefer to crimp and solder everything. Takes time and practice, like everything else.

Mr. Turner is starting from nowhere and has bit off some pretty big projects. I remember what my first forays into car repair looked like, so be gentle! He's not doing everything "right" yet but no one did their first times out, and he's good about taking advice.

That comparison to a house really puts things in perspective. I had no idea that the draw was anything close to a house.

Thanks Dave!

[Mrturner1]

Originally Posted by indymachinist

That alt wiring looks... not all that great. What gauge wire is coming from the main alt. post?

It's 10 gauge wire, but it looks very old (if that matters) I got a new 2 wire plug and a new eyelet to go on the stud in back of the alternator. I also got a roll of 10 gauge wire and I'm just going to make a new harness for it. At least then I can rule that out.

[Mrturner1]

I left the alternator at the shop over the weekend. If he can make it 120amp for a decent price I'll probably go that route. He says with the rotor/stator he uses he can get 70amps at idle rpm which is where I'm having the trouble.

When I re-wire it, should I use something heavier than 10 gauge?

Also, the instructions on the Flexalite setup said to wire the relay/temp knob box on the drivers side, which is about 3 feet from the battery. Should it be on the battery side?