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stepping stone 11-24-2012 08:53 PM

Going thru alternator belts???
I am going thru alternator belts on my 86 Catalina 30' with a Westerbeke XP25 motor with 850 hrs on it.
The first problem I noticed when I bought this boat 1 year ago was the belt seemed lose, so I bought a new one and kept the other one as a spare because it looked fine but the proper tension was not able to be achieved, but after putting the new belt on it was a little better but not much, the bracket doesn't go out far enough to get proper tension on the belt? so the belt vibrates so much it hits the hose clamp for the impeller, hence wearing out the belt in less than 20 hours.
1. Is this a bad manufacturing issue?
2. Has anyone here had this problem, and if they have, what was the fix?
3. The belt lasted less than 20 hrs (thankfully I had a spare!!!)

I would appreciate any good advise, tired of changing the belt and cleaning all the black rubber from inside engine compartment its a mess. thanks in advance guy's!

SchockT 11-24-2012 09:08 PM

Re: Going thru alternator belts???
It sounds like the pulleys are misaligned. That will cause the belt jump you describe as well as the rubber dust. If the belt has been slipping alot the pulleys could also be worn so the "V" groove is more like a "U".

If you can't get enough tension on the belt, then it is probably too big, just buy the next size down.

Maine Sail 11-24-2012 09:12 PM

Re: Going thru alternator belts???
On this engine there are a few possibilities.

1- You need the right length belt. Likely .5" shorter than the one you have and NAPA can supply you with a few sizes on either side until you get the right one..

2- You need to properly align the alternator with the rest of the pulleys. If you have the upgraded bracket it can be forward or aft aligned. If you have the old style alt bracket it really needs the upgrade. Most "XP" motors had the upgraded alt bracket..

3- You need to clean any rust off the crank, alt and water pump pulley belt mating surfaces..

4- You need to make sure the alternator pivot bolt is the proper size. Many of these engines shipped with bolts that were too small and allowed the alt to "twist off" under load. The pivot bolt should be a snug fit, with minimal to no slop, through all pivot holes.

5- The adjuster arm bolt should be made longer so a nut can be put on the back side of it. Simply threading into the alternator ear can lead to these bolts getting loose.

These 5 things will make a huge difference so long as the alt does not exceed the capacity of the 3/8" belt, or about 80A - 90A...

stepping stone 11-24-2012 10:00 PM

Re: Going thru alternator belts???
Man thanks a bunch guy's!
I'm on it the bracket is what is first on my list,
1. Done the cleaning.

2. Checked the pulleys to see if they had wear.

3. Checked alignment. (tuff to see, but they look aligned.) It doesn't seem there is any place for realigning anyway?

4. Sent a message to Westerbeke a minute ago to see about getting the upgraded bracket.

5. Also going to Napa, to check out there belts, went to our local boat part supplier and they didn't have a great selection of belts that went down 1/2" in size.

6. Did you mean 3/8" in width or depth?

7. Thought of making a extended bracket, but if there is one that has been made I'm buying it!

I will let you Know if it works. Thanks guys for the help. I think I'm on the the right tack now.

bljones 11-24-2012 10:03 PM

Re: Going thru alternator belts???
Don't check alignment by sight- use a straight edge (like a metal ruler, or at least a length of steel or aluminum flange) across the pulleys. Mainesail has nailed the solutions previously.

aeventyr60 11-25-2012 02:17 AM

Re: Going thru alternator belts???
Check the bearings on the alternator pulley as well, when they start to go it will wobble.

OPossumTX 11-25-2012 02:46 AM

Re: Going thru alternator belts???
I believe Maine Sail has put you on the right track. Classic symptoms of starting with too long or a wrong width belt. Alignment is another frequent cause of destroyed belts but unusually extreme miss alignment will cause them to wear out and then flip over. If the same belt is driving other loads, pumps or something else, a bad bearing in one of the other loads can cause a belt to fail quickly.

Good Luck!

stepping stone 11-25-2012 02:42 PM

Re: Going thru alternator belts???
Bought the belts from Westerbreke for this motor and had it double checked this week, its the right one.
It is mainly a tension thing none of the belts get tight enough there is a 1" slack in the belt and I know that not right. but you raised a question about the alternators pulley being loose and causing wobbling, I didn't check that but it wasn't apparent when putting the new belt on. Anyway it wasn't a sided to side belt wobble, but I'm going to check alignment and the alternator pulley anyway. and I'm going to extend the bracket also about 1" so I can get the tension I need.
I was on the other Catalina forum this morning and read where another guy had used the double pulley system kit for his XP25, he was having the same issue as I, so I'm going to check on that also. I do have four batteries plus a starting battery so I may have a large 100 amp alternator, I will check that out as well, and check to see if I have the right pulley on the alternator, they said that could be the problem also if alternators were changed out to accommodate the extra amperage needed to charge those batteries.

SloopJonB 11-25-2012 04:10 PM

Re: Going thru alternator belts???
Use a cogged belt as well - they transmit more power without slipping compared to standard V-belts. You definitely need a shorter belt if you have an inch of play.

stepping stone 11-25-2012 10:35 PM

Re: Going thru alternator belts???
Thanks, I will check that out, good luck finding the boat half the fun is walking the docks to find your mate.

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