Belt Tensioner Bad?

Hey guys, my old belt tensioner went bad (bearings) so I replaced it with a jobber piece not a Ford piece. I was also fraying belts, which i thought at the time was the tensioner but it was actually my hood liner rubbing on the belt and fraying it. Now I am throwing belts like crazy but only when i am doing a burnout at the track. It's pissing me off, I can't do one run without the belt shredding. When I do a second gear burnout for about 8 seconds and let the car out it seems like the tensioner must load and unload hard and throw the belt. It never does it on the street even if I hammer it. What the hell is going on? The belt tensioner seems loose too, not as in bolt loose but just tension wise. When you put the breaker bar in the tensioner so you can put the belt on the belt is real easy to get on all the pulleys. I'm just wondering if this tensioner does not have enough strength to handle the load of the belt when it is torqueng on the motor? Anybody have any ideas? Should i go back and try a Ford tensioner? I've made three passes on the last two race weekend and every pass has thrown the belt. Last night I tighten the belt down as much as I could with the two idler pullies on the blower and it still threw the belt coming out of the burnout. I am seriously pissed.

RandyStinchcomb said:

when you replaced the tensioner, did you put another aluminum one back on? Ford has an improved "steel" tensioner, it's $$$ but doesn't flex like the soft aluminum arm tensioner does, which will cause belts to flip and shread.

I'd go to a Ford gealer and get the steel tensioner kit, comes wth a new belt and is pricey at @$140.00. par # is X3RZ-6B209-DB and I have plenty if you can find one locally

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Awesome Randy! Ya it is an aluminum jobber piece of S@#T! I'll see if I can get the part from one of my local dealers, Big M Lincoln Mercury or Rodeo Ford. I have a fleet of 150 Ford F350's-550's so they give me really good deals on parts. Even still here in Canada I get raped, if it's $140 for you it will probably be $200 for me up here. I can't use the factory belt, won't fit with the blower. The jobber part I got still cost me $90 from another auto parts store I use. I definitely want the steel one. Thanks again Randy !

I'm gonna pick one up Monday or at least order it Monday if they don't have it in stock. I'll let you know if it helps the problem. If you get one on before me let me know. I wanna get this problem fixed.

OK, here's the results. I ordered the Ford Tensioner, got the car up and ready to be torn apart and then took the tensioner off. Needless to say I didn't have to go any further to find the problem. Here's the results. look how bent that piece of crap is.








The bolt bosses on the aftermarket tensioner were too thick and as the tensioner would move it would catch or hold up, it snapped the bump stop piece that is supposed to keep the tensioner from flexing to far right off. Needless to say the Ford piece is way better quality. Thanks for the help Randy!