Serpentine belt trouble

[JoshHefnerX]

I'm in here late but a long straightedge across the face of the pullies would have magnified any misalignments.

 

[BoondocK5]

I'm in here late but a long straightedge across the face of the pullies would have magnified any misalignments.

It’s pretty tough to get anything down in there across any of those surfaces.

 

[imiceman44]

If it's coming off with just the starter motor, something is really off. Your mount may have the compressor at an angle. If you can get an angle finder on the clutch and the crank, that verifies in that direction, then a straight edge should show if it parallel to the front of the block. https://www.gatesaustralia.com.au/~...anincreasebeltdrivewhitepaper-performance.pdf

I don't think you want the belt riding against a stationary object. If you make a guide, it should be part of the pulley, so it's turning. At least as proof of concept, you might be able to swap the smooth tensioner pulley for a ribbed one, since they have sides on them. But still, any misalignment of pulleys will make the belt wear out faster and the noise may be obnoxious.

I don't know if you have this figured out yet but I agree that most likely something is not at the right angle.
If your pulleys seem to be in the same plane, I suspect the modifications you made on the brakes might be a little off.

 

[BoondocK5]

I still need to go out and make a measurement from the front of the block to the first rib on the compressor, then, do the same on another pulley.
Then remove the difference on the backside of my AC compressor bracket. I’m convinced this is the issue


I procured this picture from the 8.1 thread in the engine forum. Thank you Larry.
The bracket on the left is the one I chopped up and rewelded stuff onto to make my AC bracket.

 

[BoondocK5]

OK, I was finally able to break free for a minute and take some measurements. The measurement at the AC compressor pulley is 5-1/8”
The same measurement at the crank pulley is 4-5/16”
A difference of 13/16” or 0.8125
The difference between the Silverado series(smaller) and the GMT400 series(or larger)
So, I need to shave off 13/16” from the backside of the AC compressor bracket.

 

[Blue85]

Well that's a dang lot. Assuming the measurements are right, that easily explains why the belt wanted to fly off.