How to set belt tension. (1 Viewer)

[Jesper]

Is there a reliable way to determine the proper belt tension without the specialty tool referenced in the FSM? In the past I've spitballed it, but it always makes me wonder if it's right, especially after reading posts about people overtightening their belts and damaging stuff. I'm installing the idler pulley-in-lieu-of smog pump with new proper belts and want to ensure things are done correctly.

I've seen a couple inexpensive tension gauges on Amazon and such for under $20 but never used one.
Input?

 

[klinetime574]

I've always just removed the "tensioner" and pulled outward on the idler(Smog pump)/alternator/AC and set the lock. Then snug up the tensioner, but do not use them to set tension, only to hold the position if the other comes loose. With good OEM belts I've never had any issues.

 

[surfpig]

Is there a reliable way to determine the proper belt tension without the specialty tool referenced in the FSM? In the past I've spitballed it, but it always makes me wonder if it's right, especially after reading posts about people overtightening their belts and damaging stuff. I'm installing the idler pulley-in-lieu-of smog pump with new proper belts and want to ensure things are done correctly.

I've seen a couple inexpensive tension gauges on Amazon and such for under $20 but never used one.
Input?

Like THIS one? They work pretty good, especially for the price.

 

[Output Shaft]

Believe it or not.... A long time ago I purchased an expensive Burroughs belt tension gauge. Just like the one illustrated in the FSM. I wanted to set the belt tension "perfect". Yeah right.

Those gauges don't work well on the 2F notched belts at all.

The big rubber knobs on the inside of the belt are difficult to align with the clasping fingers of the gauge.

The gauge can only be used on the upper ALT/PS belt anyway. It can't reach the other belts.

Even after using the gauge on the upper belt (the only one that it could reach) there was considerable uncertainty as to whether the belt was tensioned correctly because each time the belt tension was checked with the gauge, the reading was a little different.

After playing with that gauge a bunch on the one belt, and then feeling the tension of the belt by pressing my finger down on the belt.... I came to the conclusion that the gauge was now worthless to me and I ended up tossing it.

The correct tension to apply to the big belts is as follows..(or at least the method I use).

Adjust the belt tension so that when your thumb is firmly pressing down on it, but not jamming down on it, the belt deflects about 1/2" to 3"4".

You want the belt just tight enough so it does not slip or jump the pulley.

Observe the middle of the belt when the engine is running. It shouldn't be bouncing up and down.

When you press down on the middle of the belt firmly with a finger/thumb, your impression should be that the belt has some flex in it, but not loose. If you press down on it and it feels real tight. It is too tight.

 

[MickTLC]

All good information above. My mechanic said you should be able to twist the belt between the pulleys 90 degrees. If more than 90, it is too loose. If less than 90, it is too tight. This has worked for me so far...

 

[gregnash]

I have one of the little tension gauges like @surfpig linked.. Has always worked great and cost me like $15 at NAPA.

 

[Jesper]

Thanks for the replies. I've been using the "twist it 90" method and the basic thumb-push method, but I don't have as much confidence in my "feels" as some of you more experienced types around here.
Yes, Surf / Greg that is actually the same one I was looking at...may give it a whirl.
Thanks again.