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[BillG]

I installed a new Balmar  712 alternator a couple of years ago and have had a recurring problem with a fine black belt dust in the area of the alternator pulley.  In retrospect, I believe that the PO probably had the same problem with the old alternator as well.  When first installed, I had cut off part of the 2 inch foot so I could use spacers to properly align the pulleys.  Problem not solved, so I spoke to Balmar who suggested changing out my Gates belt to a Top Cog and reducing the power output from 100% to 90 %.  Still no relief, so I read thru all the past threads on this site and decided to take off the alternator bracket and check it out, it look bent so I have replaced it with a new one as well as changing out the original pulley that came with the alternator with a new pulley at the recommendation of Balmar.  I accomplished that yesterday, but still think I have a problem.

When you take a straight edge across the face of the engine pulley to the face of the  alternator pulley, they don't seem to be on the same plane.  What I mean by this is that the straight edge sits perfect flush along the engine pulley and then touches the alternator pulley at the far side only with approximately 1/16 inch gap between the far side and near side of the  alternator pulley.   I don't see how there is anyway to adjust that angle without litterally shimming the bracket away from the engine.

Has anyone else confronted this problem or is it something I have to live with?

[wind dancer]

I recently installed a Balmar 61-80 and noticed a slight bit of dust right after installing it with a new Gates belt, which stopped over time.  I think it can handle a tiny bit of misalignment.  So far, no other problems.

[dave davis]

I will be following this subject very close, for I too have had this black dust problem for many years. My boat is # 707 which was built in 1988. I still have the original alternator and I think CY/Universal upgraded the alternator bracket just prior to my boat. The last time I compained to a mechanic about the black dust, he installed a new belt and told me that there is a brake in period before the belt fits the pulley. He also told me to take some fine sandpaper and touch up the belt edged very slightly. He also told me that the belt is too loose and the black stuff is the result of the belt jumping up and down.
I was at the boat shoe yesterday and I had a nice talk with the Rep from the Universal Engine. They had the latest model on dispay. I saw how supper tight the belt was. There is no way I could tighten my belt that tight by using a stick in the right place and pulling like crazy. He told me that I would need to use a "belt tensioner" and than tighten the bolt. That is going to be my next try and I hope the belt and bracket can take the additional stress.
Maybe i will have to take a better look at the alignment. thanks for that input.
So far none of these suggestion have stopped the black dust.
Dave

[Ron Hill]

Bill : You've got the correct procedures. 
Now you have to play around with shims(washers) to get that straight edge to set flat on both the drive and alternator pulleys!! 
You might want to purchase a belt tensioning tool from Harbor freight or NAPA auto parts.  Think they might cost about $10 now -a great tool making belt tensioning a breeze. 
As I wrote in the Mainsheet - take your fingers and you should only be able to twist the belt about 90to110 degrees.  That's about the correct tension (shade tree mechanic) check!   

[Stu Jackson]

I tried finding the belt tensioning tool on Napa and in the stores, and also asked about details in earlier posts.

I would like to find one, so, Dave, if you find one, please buy TWO of 'em.

[Steve Hansen]

Here is a link For the alternator tightener

http://www.jcwhitney.com/autoparts/Search?catalogId=10101&storeId=10101&sku=15ZX6161X+&searchbtn.x=6&searchbtn.y=8

Steve

[Stu Jackson]

Thanks, Steve, been searching for this for years, even after Ron told us it was available (somewhere).  Glad we found the "where."

[Tom Glennon]

I was under the impression that there was supposed to be about a half inch deflection in the belt, and if too tight, it would damage the bearings.  Perhaps my belt is too loose.... hence the black powdery stuff I have going on inside the engine compartment!

[Stu Jackson]

Tom, you're right about the deflection test for correct tension.  My new belt was loose enough that some could say it was simply "slapping around."  Too tight or too loose, either way makes black dust.  I'll bet that black dust comes with perfectly aligned and tensioned belts, too.  I'm making this up: It's call NEW belt syndrome, and until the black stuff they put on the outside of the belts wears off, everyone gets black stuff all over!!!

I got my tensioning tool today and will go to play with it and let you know.

[Stu Jackson]

This continues at: http://c34.org/bbs/index.php?topic=3667.0

[BillG]

Well, I think I have finally solved the problem.  In fact, the bracket that holds the alternator onto the engine did need to be shimmed.  When I purchased the bracket  new this winter, I noticed that the angles weren't 90 degrees but were just a few degrees in excess of  a 90 degree angle.  By shimming it, I increased this angle even more, but I now can place a straight edge across the faces of both the engine pulley and alternator pullley and have it sit flush.  Will let you know at the end of the season whether I still have a belt dust problem.

[Bob K]

When I purchased Prosit, the alternator bracket was bent, and this was causing misalignment ( and plenty of the dreaded black dust).  The bent portion was the fore and aft section that bolts to the side of the block.  It bent just forward of where it bolts on to the block. Not sure how it bent - but I bought a replacement and had a triangular plate welded to give it extra strength.  Still get some dust, but much less.