Ok here's the story. The bolt for the tensioner broke. So I pulled the bracket to remie TW broken bolt and while it was out I decided to remove the smog pump as well. So all said and done I found the 94.5" belt to fit good without the smog pump in place. And it was runnin good but the belt seemed to run on the back side of the tensioner pully. Well today it decided it didn't want to stay on the tensioner. The belt keeps working toward the engine and falling off the tensioner (thank god I did an e-fan swap or it would have eaten the belt). I tried another aftermarket tensioner and a ford one as well and still have the same issue

And suggestions?

 

I noticed in one of your other posts that you put in a spacer to tighten the new belt set up. could this have changed the horizontal axis of that pulley? that might direct the belt in a particular direction. Just a thought.

 

When I put the larger pully from my 95a 3G alternator onto the 130a in the truck it took up that slack and I removed the spacers. I'm going to try the small pully again with the spacers again tomorrow belt flew off a block from my work thank god lol so i parked it there and got a ride home. Atleast I have the shop to work in now....

 

What I have found with the aftermarket pulleys is that they don't fit on the tensioner correctly. And the aftermarket pulley will tilt a hair and cause the belt to run off. This has happened a few times to me and I finally figured it out. You'll need a very thin washer or shim behind the pulley, and a normal and flat washer on the outside.
One of the trucks the pulley bearing rubbed on the tensioner and needed the super thin washer on the back, but all of them needed the washer on outside because the bolt tightened on the tensioner before the bearing. Almost can't tell it's not right.

Check it out and let us know the solution.

 

The problem is belt runs off the inside of the tensioner spacing it out will make it worse.
I have tried 2 aftermarket tensioners and even went to the junk yard and got a oem for one and same issue

 

I replaced the complete tensioner each time too not just the pulley

 

Hmmm
Interesting.
I gotta look on my truck for more ideas I guess.

 

Now that you have removed some items from the serpentine belt loop what is on either side of the tensioner? can you shim these slightly to aim the belt at the center of the tensioner? I.E. put a small shim on the side that faces the tensioner to bring the belt out a bit?

 

Nope, tried a shim behind the alternator pully and didn't do anything. The tensioner now sits between the alternator and the crank

 

By crank you mean the one coming out of the water pump that used to have the manual fan attacked to the front of it before you went with an electric fan? here's a wild idea, maybe with the forward pressure of the fan gone the one on the crank has settled back a bit, is it adjustable?

 

No by crank I mean the harmonic ballance on the crank... Lol

 

like this

 

I'm just shooting in the dark here lol. Short of spacing the things around it forward on their mounts??????? I restored a really neat all in one woodworking tool with a buddy once. It had one 220 electric motor on it and pulleys/belts going to a tablesaw, bandsaw, planer, router table, etc etc. We literally had to line the pulleys up with a laser after we were done.

 

i dont understznd what could have changed... all i did was remove the smog pump

 

smog pump could have been bumped out a bit, pulling the belt outward from the crank. How many of these things we do to our truck are like a hand of cards?