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lateral · 06-07-2016, 11:40

Quote:

Originally Posted by puffcard

That might be ok for a car or low output alternator, but not 120amp setup.

A changing system putting out 120amps requires 2.25hp, thats a good load. The raw water pumps which only need about 1/8hp can run much looser.

745watts = 1Hp
14V x 120amps = 1,680 watts
1,680 watts/745 = 2.25HP

.

At 60% efficiency for V belt system (if you are lucky) 2.25/0.6 =3.75hp
Rule of thumb, IIRC, is 20-25A /hp = 4+
Definitely will give Dayco belts a try.

jacktheflyer · 06-07-2016, 11:51

Have to ask, where does the belt dust go? I can tell you where a lot of mine went, into the engine is where. The factory Yanmar "air filter" isn't much for filtering, assumption is I'm sure that boats don't operate in dusty environments, but if your making belt dust, most likely your engine is eating a lot of it.[/QUOTE]

Belt dust everywhere which makes for untidy engine bay.

lateral · 06-07-2016, 12:12

Quote:

Originally Posted by jacktheflyer

Have to ask, where does the belt dust go? I can tell you where a lot of mine went, into the engine is where. The factory Yanmar "air filter" isn't much for filtering, assumption is I'm sure that boats don't operate in dusty environments, but if your making belt dust, most likely your engine is eating a lot of it.

Belt dust everywhere which makes for untidy engine bay.[/QUOTE]

+1
I didn't consider how much would go into the air filter.

Tempting Fate · 06-07-2016, 16:45

Most alternator belts wear out because of either alignment or slippage. Getting a serpentine belt is step one to handle the load. {I also like Gates Green Stripe} If you see belt dust and/or hear a bit of a squeal at starting, simply spray water on the belt. If the sound goes away, alignment is off. If it gets worse, belt tension is off. Don't use the 'finger depression test." Get a tension meter. Cheap and effective. Also, many 120+ amp alternators require two belts and pulleys to work efficiently.

Sberg · 06-07-2016, 21:06

I got one electromaax serpentine kit to test out on our Portside 3YM30 a year or so ago. Beautiful gear.
But alas, once all installed, the pulley for the alternator was 5mm further out than the crank pulley and water pump pulley. The alternator has no movement fore/aft so I couldn't get good alignment. (3.15" saddle mount) Their suggestion when emailed was to purchase one of their alternators or machine the pulley down. I didn't actually need a larger output alt, was just tying to reduce belt dust.
I thought that I had read on their website recently that they now have two different pulleys but I can't find it again. Anyway, after numerous emails with no reply, I gave up and reinstalled the original pulleys.
I'm sure the serpentine belt would help stop belt wear but with the stock 80A hitachi, you would have to muck around a bit to get all pulleys aligned. (Unless the design has changed)
I see that the new 3YM30AE now has serpentine belt and larger alternator
So if going down the electromaax serpentine belt road for a 3YM30 and keeping the stock alternator, get confirmation that it now fits.

Sent from my iPhone using Cruisers Sailing Forum

Jd1 · 06-07-2016, 21:23

Quote:

Originally Posted by Sberg

I see that the new 3YM30AE now has serpentine belt and larger alternator
So if going down the electromaax serpentine belt road for a 3YM30 and keeping the stock alternator, get confirmation that it now fits.

.... and take whatever electromaax tells you with several pounds of salt ....

Sailorman Ed · 07-07-2016, 10:06

I too have had abnormal belt wear on both my 2GM w Haitachi 55A.
I found that the holes in the alternator with 10 mm dia while the hole in the engine casting was less than 9 mm and the bolt about 9 mm. So I ordered 10 mm bolts, carefully drilled out the casting and put on a new YM belt. After about 12 hour, it needed tightening. Then 14 hours later, I notice the top of the belt was below the pulley and needed tightening again. The alignment "looks" OK ( will check with a longer straightedge this WE). Based on this, I am expecting only about 75 - 100 hours out of the stock belt...seems way too short. it cannot be the alternator load as I have plenty of solar and with both engines running, the load has to be small. Is heat a factor?
Ed

**a64pilot** · 07-07-2016, 11:06

Quote:

Originally Posted by Jd1

.... and take whatever electromaax tells you with several pounds of salt ....

I would personally be very hesitant to purchase anything from them based on numerous reports I have seen.
We have a Vendor or two here that will sell you the Balmar kit.

jacktheflyer · 16-03-2017, 23:44

Quote:

Originally Posted by Sberg

I got one electromaax serpentine kit to test out on our Portside 3YM30 a year or so ago. Beautiful gear.
But alas, once all installed, the pulley for the alternator was 5mm further out than the crank pulley and water pump pulley. The alternator has no movement fore/aft so I couldn't get good alignment. (3.15" saddle mount) Their suggestion when emailed was to purchase one of their alternators or machine the pulley down. I didn't actually need a larger output alt, was just tying to reduce belt dust.
I thought that I had read on their website recently that they now have two different pulleys but I can't find it again. Anyway, after numerous emails with no reply, I gave up and reinstalled the original pulleys.
I'm sure the serpentine belt would help stop belt wear but with the stock 80A hitachi, you would have to muck around a bit to get all pulleys aligned. (Unless the design has changed)
I see that the new 3YM30AE now has serpentine belt and larger alternator
So if going down the electromaax serpentine belt road for a 3YM30 and keeping the stock alternator, get confirmation that it now fits.

Sent from my iPhone using Cruisers Sailing Forum

Do you still have the kit you removed?

Sberg · 17-03-2017, 02:52

'Do you still have the kit you removed?'
JackTheflyer,

It's a long story but it is being returned.

phildy · 09-12-2019, 14:50

I have the new Yanmar 3YM AE which features a serpentine toothed belt. Can anyone tell me if there is an equivalent belt to the factory Yanmar belt , available at a more reasonable price