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Beta 43 alternator belt tightening


DaveR

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Good morning,

 

I have just changed the alternator on Legacy (Beta 43, 100A) and I am having difficulty getting the belt tight enough to stop it squealing.

 

I resorted to using a ratchet strap round the body of the alternator to a strong point and gave it full pull (theoretically 1 tonne). I tightened the bolts but still have a mild squeal as the demand on the alternator increases.

 

Obviously there is a special trick to do this job. Unfortunately I do not have the special socket to fit the center of the crank pulley and so can not put the belt on after adjusting the position of the alternator.

 

Any other thoughts please?

 

Thanks Dave R

Edited by DaveR
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I presume this is the wide flat multi-groove belt. Check that the adjustment is not bottoming out, the belt has to be tight but not by rediculous amounts. You could also try a new belt, and also clean the pulleys to be certain there is no oil on them.

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I presume this is the wide flat multi-groove belt. Check that the adjustment is not bottoming out, the belt has to be tight but not by rediculous amounts. You could also try a new belt, and also clean the pulleys to be certain there is no oil on them.

I wondered if it was Vee or Poly-Vee. If it has been squealing for some time it is possible for the pullets to become highly polished thus loosing their grip.

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For the little vee belt engine alternator, I use a bar to apply a little pressure by levering the alternator away from the block. The big groove belt domestic one has a bolt arrangement to force the issue. Neither of these are difficult and you'd have spotted that big bolt if you had one, so I guess your Beta 43 is an older version than mine. It's all very clear in the Beta manual though, and these are available on line free.

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Don't have the belt over tight as the alternator bearings will have a greatly reduced life.

When the alternator is fully over, so belt is as tight as it will go, how much belt deflection is there under a firm thumb push?

If too much the belt is not tight, so possibly the adjuster mechanism is not right, or the belt is too long.

 

If the belt is correctly tensioned then it may slip due to oil etc, so give the belt and all pulleys a clean.

 

If all else fails you can get anti slip spray, something like this.

https://www.amazon.co.uk/Rocol-34295-300ml-Dressing-Spray/dp/B004Z0XYJU

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Based on experience with the larger Beta engines:-

  • If it's a basic (traditional, solid) V belt replace it with a cogged version - inexpensive by post from Bearing Boys.
  • If a poly-V - flat belt - not a lot you can do get a new one
  • Do NOT overtighten either sort - cos that won't work
  • Beta will (should) sell you one of their tensioner thingies - ring them up, give them the WOK number = engine serial number.
  • One reason I found for belt squeal was running the engine too slowly when charging the batteries, run at 11-1200 rpm for the initial charge.
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Also important to check that the main pulley isn't working loose on the crankshaft...

It is on a taper with a 'key'....

 

The taper..wears itself into a groove on the shaft if it starts to wobble...

In the early stages...you may not spot this...

 

Cop hold of the edge...and 'wobble' it about to make sure....

If its wobbling..its retrievable....but if it works badly loose..its not

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Bobbybass, on 02 Jun 2016 - 1:59 PM, said:

Also important to check that the main pulley isn't working loose on the crankshaft...

It is on a taper with a 'key'....

 

The taper..wears itself into a groove on the shaft if it starts to wobble...

In the early stages...you may not spot this...

 

Cop hold of the edge...and 'wobble' it about to make sure....

If its wobbling..its retrievable....but if it works badly loose..its not

 

Good point.

If the engine has the power take-off splines in place, you can buy an adaptor from Beta - depends on your pulley configuration.

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Small alternator belt should have 1/2 an inch flex on the longest run. Use a long screwdriver or small pry bar to lever the alternator away from the engine block whilst you tighten the bolts.

 

Large alternator you should be able to turn the belt through 90°on its longest run. As said, adjusted by a bolt which moves the alternator body.

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Small alternator belt should have 1/2 an inch flex on the longest run. Use a long screwdriver or small pry bar to lever the alternator away from the engine block whilst you tighten the bolts.

Large alternator you should be able to turn the belt through 90°on its longest run. As said, adjusted by a bolt which moves the alternator body.

Earlier B43s didn't have the adjuster bolt and the domestic alternator had to be pry barred the same as the engine alternator. I know, I had one.

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Thanks for the ideas. Been on the cut out of internet coverage. What I have found is that the belt squeals at the start when the demand is about 40 amps. When the Sterling controller kicks in and the demand goes to 90 amps then all is quiet. This is the opposite to what I have been used to.

I do have a spare belt and I will fit and give the pulleys a good clean off with some surgical spirit.

Thanks Dave r

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