Alternator/Belt Screeching after IR swap

[That4doorKiD]

After i swapped a 60 amp IR alt. from Auto zone to a 710, When the engine is running a horrible sound comes out the alternator screeching.  

 

I have the stock l-series bracket and have  loosened and tightened the tension leading to some improvements and the noise comes back. Also, the belt is wearing out super quick, so I

 

put another one on, and the sound improved, but wore it out and came back. anyone ran into this problem?

[datzenmike]

If you replaced it, it is very unlikely two were bad. Take the belt off and spin the water pump by hand. Bearing is likely gone.

[banzai510(hainz)]

belts line up ok?I think they would line up fine as a I have a 50amper also.

 

usually the 50 amper has the bigger bolt holes in the mount and the L16 uses the smaller so hop this is a tight fit otherwise I have a lot of alternator bolt breaking issues(with the L16 set up). the later L18/20s had bigger bolt pass thru hole in alt and the mount in the block

[Ratwagon1600]

1. Belt may be too loose.

 

2. As DM pointed out, bearings could be on their way out in either the water pump or the alternator.

 

3. Make sure the belt is the correct width for the pulley setup you are running.

 

4. Are the pulleys in line with each other i.e. is the alternator pulley sitting forward of the fan pulley and Harmonic balancer?.  Misalignment of these pulleys can cause for excessive wear as well.

[DanielC]

Check the voltage at the battery, before starting the engine, and after.

A 60 amp alternator can put a good load on the engine, and on the belt that drives it.  

If the battery is low, and that is possible, you did not change the alternator just for fun did you, the new alternator may being putting out close to its full capacity, trying to get the battery fully charged again.

Likewise, if something else is wrong, and the alternator is overcharging the battery, again the alternator could be putting out its full output, and loading down the engine, and the belt.

 

With the belt off, both the alternator, and water pump should spin freely by hand, and not make any noise.

[That4doorKiD]

Both alt and water pump spin freely w no noise. I notice on the alt pulley, the belt I'd slightly crooked. The alt pulley is more forward than the water pump.

[Ratwagon1600]

If your pulleys are out of alignment, this will cause premature belt wear!

[datzenmike]

Yeah you'll have to shim the alternator on the mount to move it or grind away on one side and add washers on the other.

 

I put an 80/90 amp KA alternator on my L18 and never thought about the draw. Drove around with lights and heater on and when I pulled to a stop it let out a screech like a stuck pig. I pushed the fan off and it stopped immediately. Tightened the belt and all's fine since

[That4doorKiD]

Shimmed the alt mount with a file by hand, just a bit and screech went away. 

Thanks for help