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Belts Noisy


Old Son

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When I first start my Beta 43 engine I get a sort of rattle noise from the alternator belts. If I increase the revs the noise goes away. It is far worse when the batteries are low and the alternator is asked to work hard.

 

The belts appear to be adjusted correctly, I would not want to tighten them anymore. They were replaced late last year.

 

The belts are standard shaped belts with sloping sides and a flat bottom.

 

The pulley is quite well matched, increasing revs does not increase charging by very much. I am on a 24V system and I noted 47amp charge at tick over and 49 amp at 1500 revs.

 

Is there anything I can do to cut down the rattle noise? I would point out that after about 20-30 minutes the noise goes but I'm sure it shouldn't be there in the first place.

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Both my Beta engines have a death rattle at the front until they warmed up. That's normal said-the-chap-who-I-felt-knew-his-onions / engines....

As an aside, may I suggest you use a cogged V-belt in rather than a standard plain v-belt:-

https://www.bearingboys.co.uk/Cogged-Belts-3831-c

Nothing to do with your current problem, but they do last and last and work so much better over small diameter pulleys.

(The ultimate is / are Poly-V belts, but that's another story)

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The engine is around 7 years old but has only run for about 650 hours (not on the boat)

 

I'm glad this might be a common issue. I will look at the alternative belt design. Maybe get a couple for the next change.

 

Thanks both

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Old Son, on 19 Feb 2017 - 6:49 PM, said:

Would a Poly cogged V belt be the best belt I could buy?

Umm - computer says no....

If I understand you correctly, the two are like chalk and cheese (a poor analogy).

Assuming this is not a wind-up -

A V- belt has one V- shaped section across the width of the belt and 'cogs', I prefer the name 'toothed', which reduce the 'wrap' diameter of the higher speed pulley in the set up. This has two advantages -

1. The stress on the belt is reduced (= longer life)

2. Being more flexible, it means that the smaller pulley(s) in the setup can be umm- smaller, so that they spin 'faster', with the result that you can get more poser out of a given engine speed / alternator pair.

 

A Poly-V belt has a number of Vs across the belt and is very much thinner, so it can power many devices at the same time. Have a look at any modern car...

 

If it was a wind-up, then I'm well and truly caught.

  • Greenie 1
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We had a beta 43 on our narrowboat. It had a travel power fitted so belt arrangement will be different. This had two idler pulleys fitted one for the alternators/water pump belt and one for the travel pack. A rattle usually indicated a bearing failing in those pulleys. I had to change several before Adrian at beta informed me I should be buying high temperature ones.

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Honest, no wind up. I think I have a V belt and so a Poly belt (which I am presuming is a flat belt?) wont fit anyways.

 

The polyV is a totally different type of belt and needs very different pulleys so is not interchangable with a V belt. They can handle very big loads.

The "cogged" belt is an improved version of the standard V belt so they can interchange and run on the same pulleys. Note that V belts come in a small range of thickness's and depths.

Although cogged belts have sort of teeth on the inside they should never be called "toothed belts" as this is another totally different item, a flat belt with proper teeth on the inside and able to transmit high loads with zero slip so also called timing belts.

 

.............Dave

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Umm - computer says no....

If I understand you correctly, the two are like chalk and cheese (a poor analogy).

Assuming this is not a wind-up -

A V- belt has one V- shaped section across the width of the belt and 'cogs', I prefer the name 'toothed', which reduce the 'wrap' diameter of the higher speed pulley in the set up. This has two advantages -

1. The stress on the belt is reduced (= longer life)

2. Being more flexible, it means that the smaller pulley(s) in the setup can be umm- smaller, so that they spin 'faster', with the result that you can get more poser out of a given engine speed / alternator pair.

 

A Poly-V belt has a number of Vs across the belt and is very much thinner, so it can power many devices at the same time. Have a look at any modern car...

 

 

V belt (cogged):

14731.jpg

 

Poly V belt:

poly-v-belt-drives.jpg

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I have just remembered a conversation I had with Trevor (RCR) about chatter on Betas. The OP say its from the belts so this is probably not relevant but I understand some PRM gearboxes will chatter on Beta engines and requires a special drive plate to stop it.

 

Although it should not happen with single helical gears I wonder if this is timing gear chatter, especially the engine that only does it when cold and possible with oil drained away from the teeth.

 

 

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David Mack, on 20 Feb 2017 - 1:47 PM, said:

 

V belt (cogged):

14731.jpg

 

Poly V belt:

poly-v-belt-drives.jpg

A picture is worth a thousand words - and so much more elegantly described!

 

Tony Brooks, on 20 Feb 2017 - 3:14 PM, said:

 

I have just remembered a conversation I had with Trevor (RCR) about chatter on Betas. The OP say its from the belts so this is probably not relevant but I understand some PRM gearboxes will chatter on Beta engines and requires a special drive plate to stop it.

 

Although it should not happen with single helical gears I wonder if this is timing gear chatter, especially the engine that only does it when cold and possible with oil drained away from the teeth.

 

 

 

I always wondered but was afraid to say - because of the helical factor. Certainly the sound appears to originate from that point - or in my case from the freshwater pump. My first engine had V belts and the later Poly-V, but the sound was present in both.

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So I followed that link which led me to a Google page with some advertising photos of belt spray. The first informative piece on that page (by Dayco), however, says this:

 

"In the past, simply covering a noisy serpentine belt in belt dressing would quiet that pesky belt. That’s when belts were made of neoprene. Today, you should never put belt dressing on an EPDM-made serpentine belt. Belt dressing, and other oils and solvents, may quieten the belt noise when first applied, but these oils will actually cause the belt’s rib surface to become more aggressive once they dry out, leading to even more belt noise issues".

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Can somebody measure the length of each of the belts on their Beta 43 and let me have the measurement? Hopefully some of you will have a spare they can use for this.

 

I have written to Beta and they cant tell me the length because they are adding a new floor to their stores????

 

I must say they haven't been very helpful. I asked if they sell cogged belts and they have not answered that either, I presume No.

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Can somebody measure the length of each of the belts on their Beta 43 and let me have the measurement? Hopefully some of you will have a spare they can use for this.

 

I have written to Beta and they cant tell me the length because they are adding a new floor to their stores????

 

I must say they haven't been very helpful. I asked if they sell cogged belts and they have not answered that either, I presume No.

Can you see the number printed on them, that should tell you the size

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