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Going thru alternator belts???

5K views 20 replies 10 participants last post by  rgscpat 
#1 ·
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!
 
#2 ·
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.
 
#3 ·
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...
 
#4 ·
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.
 
#7 ·
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!
O'
 
#8 ·
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.
 
#9 ·
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.
 
#11 ·
stone-
These days it is hard to find anyone who understands that V-belts come in different profiles, not just different sizes. So once you confirm that you've got the right profile, and size, you also need the right length. Usually if the belt number is something like XYZ36 that part of the belt number would indicate it is 36" long, and (duh!) the XYZ35 is then one inch shorter. XYZ34 is two inches shorter. Finding any v-belt at all in stock anywhere, not so easy.
And if someone at some time had the alternator repaired or replaced, and used a different pulley size? The stock belt length could be wrong now. Best bet is to take a good piece of string, wrap it around, measure it. If it seems like the belt you have is an inch too long, compare that to what the string measures. In the worst case you try two new belts, one an inch shorter, the other two inches shorter. Half-inch increments would be nice but at least get in the ballpark.
You may also be able to find a belt tension gauge and a belt tensioner/spreader to make the job easier. The gauge actually tells you how much tension is on the belt (hard to find these days, but they exist!) while the spreader is a turnbuckle-type gizmo that fits between the two pulleys and forces them apart, so you can tighten the alternator down in a leisurely manner while the tension is being held by the spreader.
 
#12 ·
The Universal engines are not the only ones that have improperly sized pivot bolts. Many factory engines including Yanmar, Volvo/Perkins and Universal often ship with the wrong sized bolt for the alternator to pivot on. With a 35A alt this is rarely a problem but when you go to 80A+ it quickly becomes belt dust bonanza..

Universal also shipped a number of engines where the Motorola alts had SAE holes and yet others with metric, go figure. The alt bracket upgrade, IMHO, is a rube Goldberg fix and rather poorly engineered, but still far better than the original.

Please be aware that the long alternator 3/8" bolt that comes with the kit is most often the WRONG size. It is much to sloppy a fit in the bracket. The hole in the bracket works MUCH better with a metric bolt. I replace it with a metric bolt and occasionally need to then drill the alt to the proper fit. The problem is the Motorola alts shipped in both metric and US sizes over the years. The upgrade bracket is drilled for metric but Westerbeke ships a 3/8" bolt.. Belt issues with the new bracket are often due to the sloppy incorrect bolt Westerbeke supplies. It allows the alternator to "twist off" and create uneven belt wear and creates wear on the alternator foot mount.

Also the new bracket has oval holes for a reason, but every one I have seen installed has never taken advantage of them. You may not need to but you really should align the bracket fore/aft on the motor so the belt is in proper alignment.. This may mean spacer washers under the thermostat end of the mount. The one I just did required two metric washers to shim it forward..

Sloppy Fitting Westerbeke Bolt


A much better fit:


New bolt on left, Westerbeke supplied "sloppy" bolt on right:


Forward Align


If you forward align place shim washers in the space:


Aft Align:


On the adjusting arm bolts I also go one step further.

I get a real long bolt, split washer and nyloc nut. I then adjust the arm and tighten the bolts hard. Once tight I install the "locking" nuts. I've yet to have one vibrate loose after this fix..

Alternator Ear End (gets both split washer and nylock nut. If the alt over heats it could melt the nyloc feature.)

Slotted end of adjusting arm: (this should never get hot enough to melt the nyloc if it does you have bigger issues.)
 
#13 ·
You know, that sounds like a tool I bought from Harbor Freight. Came with two different cap screws (allen bolts) to hold the handle on, and I looked at them and said, okay, that ain't gonna work. And if I wanted a correct screw, they could ship one from China in about 2-3 months. Honest.

Or the mars lander that crashed a couple of years ago, supposedly one design group was using metric specs while the other used fractional? Why should we expect any better from Universal or Volvo. (sigh) Of course Westerbleak [sic] doesn't surprise me, ordering parts from the lowest bidder is what it is.

Jeez, really, none of these folks know how to spec a round peg to fit a round hole ?! That kind of qc problem is, frankly, frightening.
 
#14 ·
If you guys would smarten up and go metric like THE ENTIRE REST OF THE WORLD these problems would cease to exist. Even the Brits were smart enough to get rid of Witworth. :)
 
#15 ·
Eh, smarten up better than our Canajian neighbors?

When's the last time you heard a Canajian carpenter measuring lumber in those handy decimeters? Nope, they still use our four by eight (foot) plywood sheets, and our two by four (inch) studs, and they cut fits to the 1/16" of an inch, not the millimeter.

Incidentally, you can't use millimeters for woodworking, because as the humidity changes, the wood changes size and the millimeters turn out to be too precise, they no longer fit.

Last I heard, Canajian plumbers aren't too fond of metric, either.

But it doesn't really matter WHICH scale you measure the parts with, as long as the idiot supplying them and machining them MEETS THE SPEC. Machine parts wear out, too. So the lowest bidder, who pushes his drills and such past their spec, winds up being out of spec every time. But hey, he's still won the bid.

That's the difference between a $1000 Honda genset, and some $500 ShenZhou POS that looks perfectly identical to it. The POS folks are using the worn out parts that someone else already threw out.

None of which really matters if you're building mars landers, of course. We all know that's simply called "The Martians only shot down two out of three!" (VBG) Curiousity's skip-and-jump-shufflebop routine obviously beat the Martian defenses.
 
#16 · (Edited)
Eh, smarten up better than our Canajian neighbors?

When's the last time you heard a Canajian carpenter measuring lumber in those handy decimeters? Nope, they still use our four by eight (foot) plywood sheets, and our two by four (inch) studs, and they cut fits to the 1/16" of an inch, not the millimeter.

Incidentally, you can't use millimeters for woodworking, because as the humidity changes, the wood changes size and the millimeters turn out to be too precise, they no longer fit.

Last I heard, Canajian plumbers aren't too fond of metric, either.
The fact that the States is still Imperial is the main reason why so much of it still exists here. Most people here under 40 years old don't use Imperial unless they have to since they were never taught it. If the States had converted back when, Imperial wouldn't exist except for restoration of old cars & boats. :)

P.S. Being an old fart, I still think in Imperial and keep my computerized dashboards set to "English", but I recognize the wisdom of a world standard measurement system. Since our money is "metric" I've never really understood the resistance to changing over. I do take issue with some metric unit sizes but that's a separate issue.
 
#17 ·
"but I recognize the wisdom of a world standard measurement system. "
Right, so you can go to any pub in any country and order a half-liter of beer instead of a proper pint.
And go to any ballpark and order a "three point three decimeter dog" instead of a foot-long frank.
As to money being metric(ish), well, maybe Loonies are, but dollars aren't. We've always had mils (tenths of a cent) but never minted them, and aside from gasoline prices they're not used in ordinary rade, never have been. Much like two dollar bills, which for some reason are easy to find OUTside the US, but no one really believes they're real inside the borders. Besides, who needs metric money when everything can be put on plastic, where computers do the rate conversions automatically, invisibly, and slipping the rounding errors into appropriate pockets?
 
#20 ·
"but I recognize the wisdom of a world standard measurement system. "
Right, so you can go to any pub in any country and order a half-liter of beer instead of a proper pint.
New units such as "sleeves" have taken the place of pints of brew

And go to any ballpark and order a "three point three decimeter dog" instead of a foot-long frank
.

Just order a dog or a "lip" - what my friends and I have called them since we were kids. A friends mother said they were "nothing but lips & noses" and they instantly and forevermore became "lips" to us. :D

As to money being metric(ish), well, maybe Loonies are, but dollars aren't.
They certainly ARE - our common "dollar" currency system is base 10 - what is that if not "metric"

computers do the rate conversions automatically, invisibly, and slipping the rounding errors into appropriate pockets?
Were you aware that was the first known instance of computer embezzlement? Back in the 60's a bank computer programmer realized that during the myriad calculations of interest each day there were endless occurrences of calculations ending in fractions of a cent. He set up the program to divert those fractions to his account and ended up rich in no time. He was caught of course.
 
#21 ·
What happens to the belts if there is a problem in the alternator, water pump, etc., itself -- bad bearings, binding, etc.? Is all happy when these components are turned by hand with the belt off? Also, what would be the effects of the deepness/thickness of the belt?.
 
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