V-belt tension

[Rupert8]

Hello,

6.9 IDI, no serpentine belt: I've just replaced my leaky fuel pump and vacuum pump. Putting the vacuum pump back I noticed some of the v-belts seem a little loose, even after a shop supposedly tensioned them six months ago while doing some other work. Since I may not know what I'm looking for by simple feel I purchased a Gates 91107 Krikit belt tension gauge to look into it. It's a cool little device, as simple as the IDI itself..... But I now realize that I don't know what kind of target tensions the various belts are supposed to be at. Does anyone have any guidance here?

The alternator belt seems to have a fair amount of movement when the engine is cold - but that being said I don't really have much experience here. With the Kriket I'm getting about 40 lbs of tension on the alternator belt, and only about 10 on some of the other accessories - the ones which the diesel shop supposedly tightened.

Maybe these numbers are just fine - but if anyone can point me in the right direction I'd sure appreciate it. Thanks as always.

 

[Cubey]

I use an old one of these to tension the alternator belt.

https://www.harborfreight.com/24-inch-general-purpose-tire-iron-93230.html

 

[Old Goat]

I don`t know what the tension is suppose to be.
For the Alternator belt, at the top of the Alternator where the bolt
screws into is a square block. Put a large open end of correct size
or a large Crecent wrench to pull the Alternator over. Then tighten
the bolt. using that I never have any blet flopping issues.

Even if the shop tightened your belts, they will stretch and loosen
up. Make them gootentite.


Goat

 

[Rupert8]

I don`t know what the tension is suppose to be.
For the Alternator belt, at the top of the Alternator where the bolt
screws into is a square block. Put a large open end of correct size
or a large Crecent wrench to pull the Alternator over. Then tighten
the bolt. using that I never have any blet flopping issues.

Even if the shop tightened your belts, they will stretch and loosen
up. Make them gootentite.


Goat

Yep, good point on them loosening after the shop tightened them. I'll re-adjust.

And yes, I grabbed the block on the alternator with a large wrench and got the belt pretty darn tight, it's just showing more vibration (like a guitar string kind of thing) than I was expecting to see. Is it possible to get this too tight to the point where it's increasing the chances of the belt breaking...?

 

[Rupert8]

I use an old one of these to tension the alternator belt.

https://www.harborfreight.com/24-inch-general-purpose-tire-iron-93230.html

Interesting. How do you use it? Across the belt or to position the alternator?

 

[tbowker]

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Here's how I do it. I use a belt tensioning tool to measure the force. I haven't had any issues.

 

[Cubey]

Interesting. How do you use it? Across the belt or to position the alternator?

Wedged next to the alternator and pulled with one hand, then tighten the upper bolt to secure the alternator. Then tighten the pivot bolt.

Just don't go crazy with it is all. It's pretty much the only good way to tension that belt on Econolines like I've had for 5 years.

I recently had a squealing belt issue after replacing the belt, and it was the alternator belt being just a bit loose. Tensioned again with the trusty old tire iron and it's been quiet ever since.

 

[Old Goat]

Interesting. How do you use it? Across the belt or to position the alternator?

That`s a HF Tire Iron. Use it or some type pry bar between Alternator and
the engine to pull the Alt. over to tighten the belt. I did that before discovering
the Square Block on the Alt. Just make the belts snug.
tbowker info above has the info you need.


Goat

​

 

[ROCK HARVEY]

I recently got my hands on a service manual. Here’s the page on v-belts:

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It says that the belt should have 1/2” - 3/4” of deflection at the widest gap.

 

[DaveBen]

This goes back aways! I have not seen this in ages!