Twisted Alternator

[Gline]

Any idea how I've twisted my alternator? I've been creating endless belt dust ever since I installed a new fresh water pump. My best guess is I bent something when using a breaker bar to put on belt tension, but I think that would have created the opposite twist that you see is this picture. I'm kinda stumped as there is no obvious issues. The alternator pulley spins great and the water pump is sitting flush, so this twist must be in the brackets or something I'm not familiar with. Universal 5432. Any ideas are appreciated!

 

[Bolo]

Just a thought….are you judging the twist by way of just looking at the photo or is the twist obvious to your eye? My guess is that your wide angle lens might be distorting the image and maybe making it look like the belt is out of line. I don’t have the same engine in my E32 but I do get some belt dust which I think is quite normal. But maybe your bracket is bent and the only way to determine that is to remove it from the engine and lay it on a flat surface to see if it’s bent.

 

[Prairie Schooner]

Great point about the distortion of a wide angle lens. One thing you could try prior to taking the bracket off is lay a straight-edge across the top of the engine and alternator pulleys and sight from above.

 

[Loren Beach]

Great point about the distortion of a wide angle lens. One thing you could try prior to taking the bracket off is lay a straight-edge across the top of the engine and alternator pulleys and sight from above.

That's really the best way to be sure. Also, IMHO, belt shedding should really not be acceptable. I used to get that particular problem with our former (OEM) Universal diesel with its stock 50 amp Motorola alternator. Pully was aligned OK, but needed a different belt than the one(s) that came with the boat. (In many ways the prior owner had not shown much interest in maintaining all of the systems of the boat.)
It used to seem like, to me, engine belts were kind of a "commodity" item, but they do vary in construction and design. I finally found a heavy duty Gates model that did not shed at all. Much Thanks goes to other owners here for advice and council regarding that problem.

Aside: this thread title would be an awesome name for a rock band!!
( "...the A&R man said I don't hear a single... the sky was the Limit...." )

 

[Christian Williams]

Check the bolt that holds the alternator by spanning the mounting ears. That would be at the bottom of your photo in Post #1.

Some have discovered that bolt to be of too-small diameter, allowing play. The cause was use of the wrong bolt size, Metric vs. Imperial. We have reports that some new alternators were shipped with the wrong bolt, or installers were not attentive to the recommended bolt size.

Worth a look. If there is play in that connection, the alternator is unstable.

 

[Loren Beach]

Some have discovered that bolt to be of too-small diameter, allowing play. The cause was use of the wrong bolt size, Metric vs. Imperial. We have reports that some new alternators were shipped with the wrong bolt, or installers were not attentive to the recommended bolt size.

Good point! After the first few years with our boat, I found that the main pivot bolt for the Moto alternator was loose; and this contributed to some wobble in the mounting. I could only imagine that it was the wrong diameter (metric vs SAE). Until I later sourced the correct size, I took a hint from the Robert Pirsig novel and shimmed the bolt with a piece of aluminum carefully cut from a drink can.

 

[Pete the Cat]

I agree that belt dust is generally an indication something is wrong. I had to fool with refastening the alternator bracket on my 25XP (just removing it and leaning on it when refastening it did the trick) and then using some thin SS washers to shim to get things aligned with a metal ruler. As mentioned, folks install the wrong sized belts regularly under the theory that "bigger is better". It ain't. The belt must lay in the groove. And pully sizes and shapes should define the belt. On the original 50 Amp Motorola on the 25XP the belt is a tiny little thing, but seems unaffected by when putting out 70%--so what the heck. When folks start mounting bigger alternators, it is easy for the pulleys, alignment, tach accuracy, etc. to go catty wompass. FWIW.

 

[Navman]

Just an idea, but do you think the mounting washer on the top arm may be causing the alternator to cant slightly? Just a thought to bounce off the hull so to speak.

 

[Navman]

Disregard previous post. The back of the alternator is tight to the mounting arm. Washer should make no difference.