If it's a new belt, it will take some miles for it to stretch.

What brand is your belt? how long have you had it for?

Correct - tensioner pulley below the top pulley.

Also - how are you setting belt tension? By feel, tension gauge, ? I usually tension it so that the belt is resistant when trying to bend it 90 degrees. I do this midpoint from the crank pulley to blower pulley.

 

I loosen the tensioner pulley. Then I tighten the belt with the 14mm tensioner below. Then re tighten the tensioner pulley.

I tighten it till it's kinda hard to tighten. I go back and check the belt and with my thumb and middle finger, try to twist past 90 degrees. Seems tough.

I have about 800miles on the belt now. and about 400 of those miles were loose without me knowing it.


I'm using the a gatorback that SOS recommended for my 3.4" pulley.

I was batting around 7-8 psi till I tightened it. Then got about 10.5 psi. and then a day goes by and I get about 9.5. Tighten, back to 10.5, then loosen back to 9.5.....

 

I almost want to recommend trying a new belt. The Gates Greenback is a great belt, but they come in limited sizes. The part #'s end in HD - for heavy duty.

It does sound like the belt is stretching and slipping; I wouldn't say anything is wrong with your tensioner system. Do you see evidence of belt slip? There would be fine power either under the hood (directly above where the pulley would be) also some dust around the cylinder head around the pulley area.

 

Just tried again. Doesn't seem to be getting any tighter.....

I can twist it a touch passed 90 degrees without too much effort. Not easy, but really not that difficult.

 

The belt I'm using is a 40" belt that SOS recommends. Should I maybe go down to a 39.5" belt?

I've tightened this one as much as I can and it's still not quite tight.....

 

Just need to confirm one thing. When you go back to readjust tension, the tensioner assembly hasn't moved from where you left it last - correct?

 

Doesn't look like it.

I searched a guy using a 39.5 belt with the same setup as me with success. I'm gonna pick one of those us tomorrow.

 

True that.

 

39.5" belt fits great.

Not really any tighter though. Doesn't seem line I can get it really that tight. I can still turn it a touch past 90 degrees.

Os my tensioner messed?

 

Doubt it. The tensioner is merely a pulley and a bolt. Is either the bolt or pulley seized?

So same problem now? You tension it, drive a while and it loosens again?