well, my belt popped off on me. the other day I happened to catch it twisted and sitting on the lip of the pulley and thought i fixed the problem but the tension felt slightly loose with alternator all the way back on the bracket and apparently it wasnt enough. any issues with going with a slightly shorter belt to give more tension adjustment? also the crankshaft pulley is slightly out of balance when car is running is that normal? thanks, Dave

 

ttt

 

Anything that spins at those speeds should not be "slightly out of balance". It needs to be balanced, just like a tire. You need to get your pulley checked and possibly replaced. It has either warped or come loose or been hit by something. As for the belt, mine is a small one and it is working fine.

BTW, I'm new to forums...what does "ttt" mean? I've seen it quite a few times.

 

dave, if your crank pulley appears to be out of balance, you may need to check the mounting bolts. it should be pretty much centered. it is possible that, for whatever reason, the pulley is not centering but otherwise o.k. it's hard to say since nobody here can see how severe you mean. if the pulley has been damaged, you'll probably notice a wobble in and out as well as up and down. it's also possible someone might have hammered on it at some point spreading or collapsing the groove. remember, the v-belt design is supposed to get it's grip as the belt wedges into the 'v' of the pulley. it should not come in contact with the bottom of the groove. if the 'v' is damaged, creating varying heights in the groove for the belt, it will cause that wobble and the belt can slip, overheat, break, twist, etc. watch the belt, not the pulley, while the engine is running. if there is any wobble in-and-out and up-and-down, you should just replace the pulley or else it's going to give you headaches.
if the belt rolled over, it's likely because it broke a cord internally. it's toast and i'm SURE you replaced the belt by now. i would also suggest you stick with the original size since a belt that breaks an internal cord will stretch an inch or two, giving you a false measurement. if you put a brand new belt on and it's still kind of loose after it's all the way adjusted, then go with the next size down.
speaking of that, when you say it's still loose, how loose do you mean? with the proper tightness, you should have about a half inch deflection when you push down on the center of the belt. this is the tricky part 'cause you have to know how hard to push to check that tension. if your not pushing hard enough, you won't have enough tension and the belt will squeal any time you start the car or rev the engine. if your pushing too hard you'll get more than your 1/2" deflection no matter how tight you tighten the belt.
also, make sure that your pulleys are aligned as best as you can get them. you don't want one significantly (no more than 1/8") ahead of or behind the other. if that is the case, you might have to shim things to get them aligned.

 

'ttt' means To The Top. if nobody responds and you need to get some attention, you post 'TTT' to bring it back to the top of the section

 

Thanks for the info.

 

thanks everyone! I am re4placing the belt today most likely(it was frayed from hitting the fan when it popped off so I just snapped it and pulled it free) I had about an inch of deflection beforehand which felt a bit loose. the pulley is erratic in its movement. fine for a few seconds then it jumps a little. alternator looks like i need to move it forward about a 1/4 inch to get it more in line. when i replace the belt i will run it again and get a better description on its actions. hopefully it is like you menhtioned, a cord broke loose and released more belt tension. thanks!