Engine Belt

[Sailmonkey]

Originally Posted by sailorboy1

maybe the first belt that lasted so long was the "special" belt

Have you measured the physical width of the pulleys? It may be that your replacement belts are too narrow?

[Stu Jackson]

Originally Posted by sailorboy1

Thanks for the replies for me to do the basic stuff. But, above was the question

I bought the boat with 888 hours in 1998. I've put on three replacement belts since then with now 3506 hours. The first one because I didn't know what the PO had done, so two changes in 2,618 hours.

[sailorboy1]

Originally Posted by Sailmonkey

Have you measured the physical width of the pulleys? It may be that your replacement belts are too narrow?

No, those belts are long gone. But both yanmar OEM belts

I have noticed that if you cross reference a belt and then look at the raw measurements that they aren’t same as he original belt a lot of times.

[Seymore]

Originally Posted by sailorboy1

Thanks for the replies for me to do the basic stuff. But, above was the question

Uh, please pardon the thread drift...

Here there's a Yanmar 3GM30F. It goes through belts quite quickly, although I have no figures (I don't bother, I just change them), because the contact angle on the stock alternator is way small. In addition, I'm told that the alternator correspondingly does not get up to rated output.

[Draughty]

Hi all
The belt supplied on my new Beta 30 broke after about 500hrs.
I tried several automotive type belts (11A1005) which stretched and powdered like there was no tomorrow.
I contacted Gates Aust who suggested "Part no 7395 this belt is a heavy duty version of the 11A1005".
I fitted one and it has performed very well; now 1700hrs up.

I came to the conclusion that the automotive type alternators fitted as standard to most small marine diesels just work too hard for too long, in too hot an environment, charging up battery banks which are too big and hardly ever completely fully charged. The weak link is the belt.

Not long after I bought my engine Beta changed to a flat Poly-V? type belt as standard; they wanted almost Au$600 for the parts to convert mine.

Rgds

[a64pilot]

I went through belts left and right on my stock 80 amp alternator, I checked alignment, made sure the belt width was correct and even tried Gates green stripe belts, I believe the green stripe is better than the regular.
http://www.gatesunitta.com/green-stripe[emoji768]-v-belt

A car doesn’t eat belts largely because it doesn’t pull as much power from them, your not charging a big depleted battery bank, just powering the car, and modern cars that do use a lot of electricity, have serpentine belts.

I went with a serpentine belt kit, that solved my issues, not what you wanted to hear of course.

When a belt starts dusting, it’s done, toss it, don’t try tightening it up etc.
Reason it’s done is it has now worn thinner and may be bottoming out in the pulley,if it is no matter how tight you make it, it’s going to slip, a properly fitted belt stands proud of the pulley edge and never bottoms out, it’s the friction of being shoved down into a wedge that makes it grip.

I’d suspect with your generator issues, your relying more now on your alternator and the belts are of course the weak link

[sailorboy1]

Originally Posted by a64pilot;2792024

I went with a serpentine belt kit, that solved my issues, not what you wanted to hear of course. [COLOR="Red"

I probably can buy 30+ OEM belts and 15 plus "better" belts. For me it's not that big a problem.[/COLOR]


I’d suspect with your generator issues, your relying more now on your alternator and the belts are of course the weak link No and nothing operationally changed between the first belt that lasted 5 years and the last one that last 7 months

There's always just the chance that I had a "good" belt and then a "bad" belt and the it really highlighted the difference.

[sailorboy1]

Well the belt I just recently put on at the start of this thread lasted about 20 hours and just came apart. I'm thinking it was just that the belt had been in storage for like 6 years as it didn't break, the green backing just peeled off starting at the seam. Lucky we heard it flapping just before turning into a narrow twisty spot and were able to just down anchor and replace. But even though I think that belt had some type of "issue" and I can not find anything wrong with alignment of at the engine, I now worried I don't have a spare and it will be days till I can get one. Think I'll cut that loose green backing off and keep it for now as an emergency backup.

[NYSail]

The serpentine belts are great and an upgrade I did when I replaced my alt. Always remember as an emergency I have heard a pair of panty hose will work in place of the belt (not wearing).

Good luck
Greg

[sailorboy1]

Originally Posted by sailorboy1

Well the belt I just recently put on at the start of this thread lasted about 20 hours and just came apart. I'm thinking it was just that the belt had been in storage for like 6 years as it didn't break, the green backing just peeled off starting at the seam. Lucky we heard it flapping just before turning into a narrow twisty spot and were able to just down anchor and replace. But even though I think that belt had some type of "issue" and I can not find anything wrong with alignment of at the engine, I now worried I don't have a spare and it will be days till I can get one. Think I'll cut that loose green backing off and keep it for now as an emergency backup.

Well the new NAPA belt appears to be doing fine. Ut hasn't even needed to be tightened since I put on. It is a cogged belt and I was reading info on it and info says the cogged belts work better on small diameter pulleys and that they run quieter. So far I would say they do acturally run quieter.

Got a new backup from Advanced Auto. It has the same number and looks the same, but was half the price. seems no consistency in belt pricing :-(

[a64pilot]

My theory is if they need adjusting the second time, they are done.
They have worn too thin by that time and may be bottoming out on the pulley and if they are, they are going to slip no matter how tight they are.
Cogged belts are made that way I thought so they can go to a smaller diameter, the pieces being cut out they way they are, and run cooler I have read.

[sailorchic34]

I use gates Green Stripe belts as they are heavy duty and seem to last a long time. I have 800+ hours on my alternator belt that was installed back in the summer of 2013 with the engine rebuild. It's stretched hardly at all.


Of course, I'm using a wimpy stock 55 amp alternator.

[NYSail]

Originally Posted by sailorchic34

I use gates Green Stripe belts as they are heavy duty and seem to last a long time. I have 800+ hours on my alternator belt that was installed back in the summer of 2013 with the engine rebuild. It's stretched hardly at all.


Of course, I'm using a wimpy stock 55 amp alternator.

That is a testament to the installers perfect alignment of the pulleys on the engine and alt....... Congratulations!

Greg

btw.... I would have an identical spare ready lol.

[sailorboy1]

I would get a new spare knowing what I now know/experienced. My “green stripe” spare belt had the backing just peel off within 20 hours and I think it was just age.