V belt deflection measurement question?

[saburai]

Hi gang!

I'm doing the 3g alternator swap on the F250 before the long south to north tow. While I've got the alternator out I'm replacing all of the V belts as a preventive measure, I'll toss the old ones in the box to have as emergency spares. Anyway, my question is about how tight to make the belts, as others have noted, they're pretty fuggin long and I'd like to get it right. I poked around the net and didn't find much objective information. The one site I found recommend 1/4" of deflection across the longest run of the belt. They gave this measurement for all of the idi belts. I trust the wealth of information and experience here, so I thought I'd ask if the quater inch deflection measurement is correct.
Many thanks...

 

[IDIoit]

good luck trying to achieve that!
the alt belt i could never get less than a 1/2" on the long side.
they are craxy long, and retarded,
which is why i swapped to serp

 

[saburai]

good luck trying to achieve that!
the alt belt i could never get less than a 1/2" on the long side.
they are craxy long, and retarded,
which is why i swapped to serp

Thanks for the quick reply!
Any issues with my using a cheater bar and doing my best to get that 1/4?
Any chance of hurting the bearings?
Thanks again for the help!

 

[IDIoit]

thats what i use. the top of a jack handle.
the bearings will be fine. if you hear the belt stretch,
you went too far

 

[saburai]

Sounds good, thanks for the clarification.
I've got a cheater pipe and a ratchet strap to pull it so I don't have to bust my nut!

 

[crash-harris]

Would've been nice if they provided a small bracket to tension the alternator with a ratchet like all the other accessories. I used a 12" crowbar to get under the alternator and tension it.

There was something to be a little careful of when doing that, but I can't rascal what it was. I want to be careful not to slip and hit...something...

Anyway, it's much tighter now.

 

[OLDBULL8]

Your best bet to get the belts tight is to purchase the Green Gates belts with the notches on the inside of the belt, they flex around the pulleys better than the solid belts. They are a little more expensive, but last a heck of a lot longer and won't squeal like a pig.

As far as the deflection goes, you would have to have a deflection meter and know how much deflection meter pressure is allowed for a given length and size belt and a chart that indicates it.

Just tighten the belts up what you would think is a minimum, if they squeal, then tighten a little more.

They would look like this. http://www.grainger.com/category/po...91675&ef_id=Vw@eDgAABfAjWivl:20160422164626:s

 

[saburai]

Thanks Gents!
Would have gone with Gates, but I've already got NAPA. My deflection gauge is my thumb
I remember seeing a belt deflection gauge when I was in tech school - in 1976!

 

[BigBlockTony]

Thanks Gents!
Would have gone with Gates, but I've already got NAPA. My deflection gauge is my thumb
I remember seeing a belt deflection gauge when I was in tech school - in 1976!

Last I knew, Gates made Napa's Belts, hoses, and premium new water pumps.

 

[saburai]

Last I knew, Gates made Napa's Belts, hoses, and premium new water pumps.

The NAPA belts looked like good stuff.

 

[MTKirk]

Thanks Gents!
Would have gone with Gates, but I've already got NAPA. My deflection gauge is my thumb
I remember seeing a belt deflection gauge when I was in tech school - in 1976!

I put new NAPA belts on mine to replace worn old Gates belts; they were identical. Had to have been made in the same factory. On another note, 1/4" deflection would be insanely tight on my truck, I just tighten them 'til they stop squealing.

 

[chris142]

I prefer dayco over gates on vbelts. If the belt twists in the pully it was too tight.they gotta be pretty tight to not slip