Serpentine belts

NYSail

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Jan 6, 2006
3,145
Beneteau 423 Mt. Sinai, NY
Hello all
Yanmar 3HM35F and a balmar 70 amp alt. I have a standard belt however was wondering about benefits of a serpentine belt. I have shimmed alt but still get minimal belt wear. What are the benefits of changing over.

Thanks

Greg
s/v Four the Soul
 
May 24, 2004
7,174
CC 30 South Florida
At 70A you are on the borderline. If it is working for you why bother and perhaps discover some new problems.
 

NYSail

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Jan 6, 2006
3,145
Beneteau 423 Mt. Sinai, NY
I was thinking about it due to the dust I am getting from the current belt..... Not a ton but I do have what I believe to be excess wear.
 
Jan 30, 2012
1,144
Nor'Sea 27 "Kiwanda" Portland/ Anacortes
I was thinking about it due to the dust I am getting from the current belt..... Not a ton but I do have what I believe to be excess wear.
Balmar reckons that serpentine belts will become beneficial at about 125 amps. I think it pays off at about 100 amps. So (theoretically) you should have no problem driving your 70 amp with near -0- dusting.

Here are some ideas in no particular order:

If you are externally regulated with the MC 614 (or 612) or ARS5 regulators you can reduce belt wear by changing the belt manager feature.

Make sure the belts fit the drive sheaves. Use a 1/2 inch top width belt. Also, since your belt drives the circulation pump try a "Top Cog" belt. Three sheaves means the belt wrap contact area on each sheave is pretty reduced. The more flexible top cog type belt will help. You can also obtain a larger diameter drive sheave for the alternator thus increasing belt contact area.

Double check that all three drive sheaves are in the same plane. Make adjustments if they are not. Very common to see sheave misalignment with fresh water cooled motor and after market bracket/alternators.

Double check the sheave contact surfaces are smooooth on all three sheaves. If not use sand paper a file or whatever to assure there are no anomalies anywhere the belt meets the sheave - no rust no nicks.

Tension the belts right. Typically belts are too loose. There are adjusters that push the sheaves apart. You set belt tension (deflection) then remove. They work spectacularly well on Yanmar motors.

There is no reason you cannot obtain very acceptable results without a serpentine conversion with 70 amp alternator.

Charles
 
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Rick D

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Jun 14, 2008
7,186
Hunter Legend 40.5 Shoreline Marina Long Beach CA
Ditto Charles

I was getting quite a bit of dust off a 90 amp Balmar with a single belt until I did as Charles suggests. I also heeded some car guys' advice to go with a Gates Green Line belt. That was eight years ago and I have only replaced the belt once and that was not for wear; just PM. No dusting even with max loads, altho the batteries are fully charged about half the time before a cruise or race.
 

NYSail

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Jan 6, 2006
3,145
Beneteau 423 Mt. Sinai, NY
Thanks all..... will shim the water pump pully out and see if that corrects.
 

Bob S

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Sep 27, 2007
1,804
Beneteau 393 New Bedford, MA
I followed Maine Sail's 90amp alternator with external regulator tutorial and installed a Balmar MC614 smart regulator on my M25XP. I had a lot of problems with belt dust and squealing if I ran my battery bank low. I would agree making sure the sheaves are clean from rust and they line up perfectly. I did do a serpentine set up on mine before trying the above suggestion. It may or may not have helped. I will say the boat is a lot quieter with it. It has run flawlessly with virtually no belt dust or squealing. The down side is it can be expensive.