New Alternator Whine/Whistle

[rebootej]

Hi guys, Ive got a 74 Satellite with a 318 and march pulley serpentine belt kit. I needed a more powerful alternator so i got the Tuff Stuff 100 amp Alternator. Has the same body case as my current 60 amp autolite only difference is that the 100a is a one wire. It bolted in perfectly but when i started engine and revved it there was now a whine/whistle coming from the alternator. Tried adjusting the tension both ways and couldn't make it go away. Got a replacement from summit and it is making the same exact noise? Has anyone used these alternators before? Its really loud and pretty high pitched. Here is a very short video of the noise but its higher pitched in real life.

https://youtu.be/BNAGofAPoNg

Any advice would help. I'm not sure what to do next...

 

[69Bee]

Why does the whine go away at the end of the video, while the engine continues to run?

 

[rebootej]

Oh sorry goes away as I let off the throttle, I had the throttle cracked for the video probably around 1600-1800 RPMs.

 

[69Bee]

It could have a larger internal fan for the heat generated due to the higher load capability. If it isn't there at idle, see how it is when you drive it. You might not even hear it, and if you do, you can always claim to have a blower...

 

[rebootej]

It definitely sounds like i have a blower. hahah And i can hear it while driving its quite loud, it sounds like bearing but i can't believe two different units would have bad bearings?

 

[bm02tj]

take the belt off and spin by hand it likely has Chinese bearings that are not right
If you feel any roughness you have it

 

[Car Nut]

take the belt off and spin by hand it likely has Chinese bearings that are not right
If you feel any roughness you have it

:yes:

 

[440roadrunner]

Have you run this long enough for the battery to normalize? You still have an ammeter? What is it doing? "Just how loud" is it? I've heard MANY seems like especially the older Delco / GM stuff whine under heavy charging load.

No disrespect, but "those movies" rarely tell me a thing. For one thing the "mikes" in many of these cameras don't give a proportional idea of sounds VS frequency. That is, they often aggravate higher frequencies, which could make the sound "worse" than it is.

If this is strictly "mechanical" sound IE blower, rather than electrical, then I don't know. "It's the aftermarket"

 

[rebootej]

It seams to turn easily by hand before installed the alternator but i have not turned it since the belt was on. Ill try that out. I know the video isn't great but figured its better than nothing. The noise is really loud like a blower or gear drive. What brands do you guys use? Id heard great things about tuff stuff

 

[idrivemopar]

Wow, I listened to it on my studio monitors, and that sound horrible, I wouldn't think its a larger impeller inside making that noise, sounds like bearing noise or could be the brushes on the stator.

 

[440beep]

I use a Powermaster 60amp alt. Trouble free.


"What brands do you guys use?"

 

[Mopar-Charger]

Just swapped my alternator out. It's the 65 AMP Dura last.

Pulley didn't line up the first time I installed it (made a nasty whine just over 1700 RPMS) added a spacer and it lined up, no more whine. Granted I have a V belt.

WISH I HAD SERPENTINE!

 

[rebootej]

I had a 60 amp on and my electric fans where drawing the battery down when they kicked on. So I need the extra power. The serpentine set is really nice moparcharger!

 

[Mopar-Charger]

I'm very jealous. How much did you get it for? If you don't mind me asking.

Only ones i've seen are well into the hundreds $$$

 

[rebootej]

Not sure what it cost... long story but the kit is about 9 years old, it was a 408 stoker that belonged to my ex gf's dad. I just transferred them to my original 318 when I rebuilt and swapped it back into the car to give him his engine back.

 

[bigmanjbmopar]

Tuff Stuff is not chinese made lol sheez Are you 100% sure there is nothing in the gaps of the alternator? maybe a scrap piece of something go in there and is hanging on the internal fan? They have a good 1 year warranty plan. What I don't get is you say you got another one and the same thing? Doesn't that rule out the alt? Are you 100% sure it's not the belt? even a tight belt could get worn and cause a similar sound.


Proof of citizenship lol 100% USA internals.

http://www.tuffstuffperformance.com/PDF/As_Cast_Alternators.PDF


Hope you get it fixed!

 

[rebootej]

Ya pretty sure there is nothing inside of the alternator. The noise is loudest by the bearing/shaft, I used a hose to listen around the engine. I've got a third alternator coming, hopefully its just a fluke that i got two alternators with issues... It's not the belt because i tried adjusting the tension looser and tighter and the noise never went away.

 

[RJRENTON]

Gentlemen,
Sometimes the noise you hear when the alternator has high load imposed on it at a lower RPM, is due to the conversion of AC power to DC power. Usually, the alternator is a three phase full wave device that is frequency dependant on the speed at which it is turning. The rotating part produces a magnetic field in the STATOR (the stationary part). In an alternator the FREQUENCY of the AC is RPM dependant. The diodes convert the AC to DC. The greater the load on the alternator, the stronger the magnetic field in the rotating part provides and therefore, the stator makes more AC power. The AC power is converted to DC power by the diode assemblies. The voltage regulator monitors the battery voltage and regulates the rotating field's power level, which in turn, controls the output of the unit (DC). One wire units, the regulator is built in; the old round back and later square back units need an external regulator to control the alternators output by looking at the system voltage or battery voltage and controlling the rotating fields power. In short....the noise you hear, unless its a mechanical noise (bad bearings or something rubbing internally) is the noise of the magnetic field induced in the stator at high load, low RPM.
Cheers,
RJ Renton

 

[rebootej]

Thanks rj but it really sounds mechanical. My first thought on hearing it was bearing. But it is weird they both did it and that the noise is loudest when increased a little above idle.

Update put the old 60 amp alternaltor back in today because summit picked the current 100 amp before the newest one got here. And the noise is gone.

 

[bm02tj]

Did you ever get the replacement and was it quiet
Bruce