We missed out on the New Years Eve Cruise because of a horrific Squeal from the alternator and the pulley was too hot to touch even after less than 2 minutes of engine running (we shut it down once the sound was identified and restarted it with the steps out in order to locate the sound)
Initial thought was that it was the Alternator Bearing - but the alternator is only 7 months old. I took it to a local Alternator shop and they tested it, bearing are perfect and the 100A alternator was loaded to produce 140A during the test, quiet as a mouse - definitely not the bearing.
I took the drive belt with me to the shop and asked them to inspect it with more experienced eyes than mine, as I pulled it from the bag the tech's 1st words - Wrong Belt! The alternator has a 1/2" pulley and that's not a 1/2" belt! General consensus is that Belt Squealed because it was slipping -
When I purchased the boat in 2015, I took the belt info and purchased 2 spares matching the original. The belt is 13/32"
Back at the boat, I measured the Crank Shaft Pulley and the Coolant Pump Pulley - both are 13/32" I also measured the Original Alternator Pulley - 1/2"
Choices: Replace the alternator pulley with 13/32", Replace the 2 engine pulleys with 1/2" or get a belt about 14/32"
Now, why did it slip? Belt Tension!
I'm pretty certain that this is the issue. The Alternator Support Arm (pic attached) has the tensioning slot and the spring washer that is between the arm and the bolt head has spread.
My solution: Make a plate to cover the Arm Slot, bent around one side of the Arm to prevent rotation.
Paul
A fender washer of the correct size will also work. The "spring" washer is also called a lock washer. Get them both at Ace for less than a dollar. Good luck on your search for a new pulley.
Thanks Ken, the guys at the Local ACE store know me by name and I know most of them, always helpful
Bolt, lock washer, fender washer, all for $1.75
:)
Paul
I really don't think that the 3/32nd difference in belt size makes that much difference. At the end of last season I too heard a loud screech from the engine and it turned out to be the fresh water pump froze thus causing the sound, check the water pump pulley and make sure it is spinning freely, if not, I'll agree that the belt tension is not correct. Fully tensioned, the belt should have a slight deflection of about a 1/4" when you push down on the belt, just make sure its tight to the touch, too much slack will lead to the screech. Good luck, my season is long over, major blizzard today in New England.
Paul,
Notice that the underside of the capscrew head is rounded, which is causing the lock ("spring") washer to spread. Switch to a hardened hex bolt. Make sure they match size.
What belt were you running?
Ken
By rights it should have a nut/lock washer (or nylock nut) on the back side, and not rely on the crappy alt case to keep it from vibrating loose.
I agree with Jeff. Had the same thought from the description. Don't overlook checking that out.
Regards,
Ed
If the wrong pulley is on the alt, it may also have a different belt angle spec.
When I upgraded my OEM 55 amp. alternator to 95 amp. I reused the pulley off of my old one to make sure it was a good match to engine. However, it maybe too late for you to try that.
I'll talk to the shop that is servicing the spare Alternator about changing the pulley and possibly changing the pulley on the one that is on the boat.
Paul
Quote from: KWKloeber on January 04, 2018, 09:06:19 AM
By rights it should have a nut/lock washer (or nylock nut) on the back side, and not rely on the crappy alt case to keep it from vibrating loose.
The 'block' that the Bolt screws into is blind drilled & tapped, so no screw threads beyond the block to host a NyLock nut.
Paul
Paul,
1) mea culpa, I was actually thinking of another install where the arm is adjusted at the alt bolt/hole. Different boat.
2) A no-thru hole is easily fixed, 'eh? Then I'd use a partial (vs. a fully) thread capscrew (grade 5 if rounding is an issue as in your pic) followed up by a nylock.
3) have you seen this arm/adjuster? :thumb: :thumb:
http://c34.org/bbs/index.php/topic,9212.msg69837.html#msg69837
Unfortunately, the "new arm" is very poorly designed (Wb? or Universal?) engineering/mechanics-wise, that is -- NO :shock: there.
There's excessive force needed at the arm slot/tightening bolt location because more of the work is being used for the arm to push the alternator AWAY FROM THE pivot/mounting bolt, and less work is going into rotating the alt ABOUT its pivot point.
The alt mount/pivot point should have been placed further to port (more material and welding = more cost :roll: ), and the alt sitting so the pivot is near 12:00 position. Then, the adjuster would be putting work into rotating the alt, rather than pushing it sideways.
k
Paul : Take the bolt that threads into the block thread and see if you can get a longer bolt so that more threads are engaged (I did that to all of the alternator bolts that threaded into the block on my engine).
Most alternator pulleys are a wide "deep V" to accommodate for engagement and wear. Are you sure it was not just a slack adjustment?
If you don't have an alternator adjusting tool - GET ONE. Look in WiKi for that where to get that tool.
A few thoughts
Thanks Ken, yes I saw the earlier post about the adjustable Alternator arm - beyond my skill/tool set!
But I did see this too: https://www.ebay.com/i/291829076699?chn=ps (https://www.ebay.com/i/291829076699?chn=ps)
I'll look at drilling the bolt hole all the way through the bracket and then adding a nylok.
Ron I didn't find the Wiki reference for that tool, is it like the one I link to above?
Thanks.
Paul
Quote from: britinusa on January 04, 2018, 03:16:55 PM
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I didn't find the Wiki reference for that tool, is it like the one I link to above?
Thanks.
Paul
Paul,
It's in the Critical Upgrades.
Yes, that's the thing. :D
A few thoughts here:
#1 You can not use a split washer on a slotted alternator adjustment arm without a flat washer between it and the arm. It will do exactly what is shown. Also always be sure that the washers bore size/ID matches the bolts OD.
#2 The flat washer that compresses on the slotted adjuster arm should ideally be an extra thick fender washer with an OD that closely matches the width of the arm. McMaster Carr is your friend in this department. Standard fender washers need not apply here and doubling them up is NOT the same as one thick washer.. I generally try to use fender washers that approach thickness as the arm material.
Extra Thick Fender Washer:
(http://www.pbase.com/mainecruising/image/166805047.jpg)
#3 A v-pulley's belt width can't be adequately measured across the top of the V then compared to another v-pully. The depth to which the "V" is cut in the billet steel can make one pulley wider at the top, or narrower, but they may both still be a 1/2" or 13MM belt or a 3/8" or 10MM belt. This is why the same belt may ride higher or lower in the alt pulley than it does in the crank. Most Universal Diesels shipped with 3/8" or 10MM belts but this engine has been converted to dual v-pulleys so all bets are off. There are no in-between sizes of v-belts for 3/8" nominal or 1/2" nominal. They are standardized such as; 3L (3/8"), 4L (1/2"), 5L (5/8") other types such as cogged, wedge type, cogged-wedge etc. are still a standardized width. Metric belts are also standardized for width such as; SPZ (10MM), SPA (13MM), SPB (17MM) etc...
#4 The alt regulator used on Paul's boat has no way to limit alt output for safely matching it to a safe belt load. It is not a Balmar regulator but rather an old Heart/Xantrex that lacks the ability to limit/de-rate alt output. Any well built performance alternator, such as the CMI/Grasser alt on Paul's boat, will pump out more than it's face value "nominal rating" when cold and even when fairly warm too. A 1/2" v-belt is pushing it's limits at 85-90A let alone anywhere close to or over 100A. Unless Paul can find a matched pair of v-belts, and install them, this regulator is less than optimal and belt wear and slippage will continue to be problem.
#5 The only good way to measure a v-pulley is with a v-belt sheave gauge. Of course the difference between a 3/8" pulley and 1/2" is easy to see with trained eyes, it may not be for one who doesn't do this every day. Please do not get hung up on sheave angles unless it is a rather gross mis-match. Alignment, sheave condition, belt tension and not overloading the belts capabilities are what matter most. The engine manufacturers could care less about sheave angles, and almost all of them have sheave angle mismatches between crank and alt, by a few degrees. I have measured these mismatches on everything from Yanmar, Universal, Westerbeke, Cummins, Cat, Beta, Nani and others. If your pulley on an alt actually matches your crank this is certainly optimal but don't count on it even with a factory installed alternator. The difference an exact sheave angle match provides is considerably less than the other mentioned items.
#6 On Paul's engine he can't do this, just a poor design when dealing with higher output engines, the arm tension bolt should be long enough to get a nut & washer on the back side. The belt tension is adjusted using the tapped ear in the alt and then torqued properly. You then install a washer (the aluminum is soft) and a nut on the back side and torque it.. I prefer nylocks for this use but a split is fine too. If your alt is getting hot enough to melt a nyloc nut, the nut is not your issue. The nylocs I use have a safe working range up to 140C or 284F. Of course 284F is far from where the nylon would melt, this would be approx 425F. If the adjuster ear is getting anywhere close to 284F (this means a diode temp of well over 320F) you have a MAJOR problem and your alt will not last long at all. You can always slide a split washer in there too but it is really not necessary if you're using a nyloc..
(http://www.pbase.com/mainecruising/image/166161693.jpg)
PS, I have also gotten extra-thick flat and fender washers from Grainger, but that's because it was around the corner and I was already picking up an order -- and it saved the shipping from McMaster.
https://www.mcmaster.com/#flat-washers/=7cd761b2fee5425cb0cce6868a7e131ejc28h5li
https://www.grainger.com/category/flat-washers/washers/fasteners/ecatalog/N-8ogZ1yzaubuZ1yzauakZpgnZ1yzauc8Z1yzauaj?searchRedirect=flat+washers#selectedFilter=ShopBy-nav
k
I found the thick fender washers at Lowes.
thanks guys.
Paul
Another potential issue; is the alternator putting out mucho amps due to battery or regulator issues. I remember discussions about how the single v belt gets overloaded as you go above 90 amps or so with the alternator installation.
Quote from: KWKloeber on January 04, 2018, 09:01:40 AM
What belt were you running?
Paul, replace the belt with a Dayco Top Cog construction (Gold if you can find the size) if that's not what you're running.
K
Thanks Ken. I'll check them out at the local AutoZone store.
The last I bought them (10+ ago,) AutoZone didn't carry Dayco but Advance Auto and NAPA did.
Paul : Gates (Rubber Co) is also a very good brand. Gates also made belts for NAPA - don't know if they still do or not ?
Just make sure that the belt is "ribbed" on the top(for cooling)
A thought