Alternator adjustment bracket

rukidn

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Apr 23, 2012
158
Catalina 310 258 Sandusky, OH
I've just replaced my failed OE Mando alternator with the Compass Marine CMI-72-IR same frame size unit. The adjustment arm was marginal before and definitely won't work with the new alternator. Has anyone found an available bracket that works to swing the alternator farther away from the engine, but not too far? Belt will of course need to be longer, so any suggestions on the bracket + belt combo are appreciated.

The photo shows the alternator folded in as tight as possible. It will be better to get it away from the engine a bit.

Thanks in advance. /Ed
 

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Ward H

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Nov 7, 2011
3,123
Catalina 30 Mk II Barnegat, NJ
Have you gone back top Compass Marine? If there is a solution he will have it.
 

rukidn

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Apr 23, 2012
158
Catalina 310 258 Sandusky, OH
I planned to email them, but wanted to start with the Forum first.
 
Feb 6, 1998
11,436
Canadian Sailcraft 36T Casco Bay, ME
There are many options here:

Option #1 This is how Beta Marine does it. All it requires is a small piece of 1/4" thick X 1" bar stock steel (any home center should have it) and no machine shop is necessary. Just clamp your existing arm to the new steel and use it as a template to drill the two mounting holes. Cut & shape is all you do. You then place the alt approx where you want it, hold the UAA up and bolt it to the alt ear then mark where the hole for the UAA needs to be then remove it and drill that hole.. You're only drilling three holes and spending $37.00 on the Balmar UAA.. You will usually need a spacer at the alt ear end but this should now be about 1/4". The UAA Balmar UAA or UBB arm makes this job easy.



Option #2 Or you can make an entire custom arm:


We prefer to see the alt with a slightly longer belt and moved out a bit into cooler air rather than crammed in behind a hot manifold..

P.S. Make darn sure the alt foot fits snugly between the ears of that OE bracket as they are cast aluminum, very brittle, and we've seen a lot of them crack. On Westerbeke engines these brackets are billet machined steel. No idea why they thought it would be a good idea to make them out of cast aluminum on this engine.
 

KZW

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May 17, 2014
827
Catalina 310 #307 Bluewater Bay, FL
Regarding the picture of the custom arm in Mainsail's post: There may not be clearance for this arm / alternator on the C-310 engine housing. There is very little room on the port side of the Universal engine in the C-310. As shown, I don't think it will fit.
Measure carefully!!!
 

rukidn

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Apr 23, 2012
158
Catalina 310 258 Sandusky, OH
Thanks. Yes I know it is tight. UAA arm just arrived and I know I'll need to shorten significantly. Essentially I need arm raised vs. the old one to increase swing radius. Alternator needs to move both up and over, but with the steps, there is limited space to port. I hope to go to boat this weekend to begin mods. Will keep you all posted
 

rukidn

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Apr 23, 2012
158
Catalina 310 258 Sandusky, OH
Sorry for the delay in posting the completed Alternator upgrade. Photos attached show the modified Balmar UAA bracket and the fabricated vertical bracket. I had to increase the belt length to a 15410. While desirable to get the alternator away from the engine, we're limited by the engine cover. My final arrangement measures 5" from end of the bracket to the head wall.

Thanks again Maine Sail for the support and suggestions.
/Ed
 

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RitSim

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Jan 29, 2018
246
Beneteau 411 Branford
Nice job. The belts come in 1/2" or 1" (can't remember for sure) increments so that is also a solution. I wouldn't change the belt any significant amount. Also the slot is a little big for that bolt size so the washers need more OD and thickness. The smaller washers will not hold as well and allow the belt to loosen.
 
Mar 6, 2008
690
Catalina 1999 C36 MKII #1787 Coyote Point Marina, CA.
As predicted my alternator bracket broke due to engine vibration on my M35B universal. I too questioned the choice of weake alloy used for the bracket.
After much thought I now agree with the choice of weak metal. With a stronger metal the engine mount portion would have to break instead. I prefer the bracket brake. So now l carry a spare bracket
Haro.
 

rukidn

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Apr 23, 2012
158
Catalina 310 258 Sandusky, OH
Thanks for the observations. Doesn't show, but I do have a spacer sleeve in the oversize slot to keep the bolt centered. Yes I could use larger washers. Also please note the spacer behind the UAA arm, essentially equal thickness to the fab'd vertical bracket which moves the arm out away from the alternator. Done over, I'd get the Balmar bracket with the integral adjuster.