Belt Help!!!!!!
 

I have an alternator belt that won't stop squealing. I changed belts and no difference, changed alternators and no difference and I even sanded the pulley grooves with a medium grit and no difference. I even aligned them the best I could and still yet again no difference. It only squeals at idle when I rev it hard or hit the gas hard on driving. Any input would be appreciated.

Re: Belt Help!!!!!!
 

Find a belt that fits's deeper in the pulley. The one on the water pump looks to be sitting a bit high.

Re: Belt Help!!!!!!
 

Both belts are almost flush with pulley itself and I don't have any problems with the belt that that goes from pump to crankshaft to power steering. Its the alternator for sure.

Re: Belt Help!!!!!!
 

Have you made sure the vee-angle of the belt exactly matches the vee-angle of the pulley grooves? My only other thought is that in spite of your efforts, the pulleys might not be in perfect alignment. Can't tell by the pic, sorry.

Have you tried rubbing a bar of soap against the belt with the engine idling? It won't fix the problem but will often stop the squealing for a short time. Just one more way of proving that's the problem belt. Usual disclaimer about keeping clothing and fingers away from moving fans, belts, & pulleys....

Re: Belt Help!!!!!!
 

The angles match pretty close, may not be exact. At first it was way off but after shimming and moving got them close with straight edge. Ill give the soap a shot tomorrow. Other than that idk.

Re: Belt Help!!!!!!
 

When you look at v belts,check that the angles are the same in this area \V/ .There are differences in belts and the actual grip from a V belt comes from the area between the slash and the v.If those angles don't match,you will have very little grip area and squealing will occur.Belts should not have to be extremely tight to grip but should be snug.Debris in the bottom of the pulley,not allowing the v area to seat down into the groove well will also cause this.I see the belt is notched on the back side which is pretty common with industrial belts which have tons of variations.Belts should also be either flush or just under the top of the pulley foor full contact thru the v area. Just some inights I have learned over the years.

Re: Belt Help!!!!!!
 

I'd think a slightly longer belt would allow alter to swing outward and downward, and give a bit more contact-distance on alter-pulley's diam. Also, use a well-known-for-quality belt. One good, usable belt that costs $18 is better to have than nine, cheap, $2-belts--same total cost--that aren't usable due to unlimited stretching and squealing. Remember to choose one that conforms to good, previous suggestions as well.
Sam

Re: Belt Help!!!!!!
 

This is the point I was trying to make in my first sentence above.... I don't think he understood what I was getting at.
Thanks for explaining it much better than I did!

Re: Belt Help!!!!!!
 

The pulley may have the contact surface worn to the point where the belt will no longer have full contact with the pulley.

Re: Belt Help!!!!!!
 

After looking at it closer the belt does sit too high, it's not flush at all and I can see where the belt is hitting in the groove and there is still untouched pulley deep in the groove. I have both the belt u see in the pic and a cogged one on the inside, but again, both sit too high. I'll have to get another one with a smaller V.

Re: Belt Help!!!!!!
 

I have a serpentine set up, but had similar problem with belt squeal. Thought I had a good belt with Dayton. Chased the problem for a while. Finally someone told me to ditch the Dayton and go with a NAPA gold belt. Problem solved. I know it's not the same as yours, but just a thought. Good luck.

Re: Belt Help!!!!!!
 

I have tried long and short belts, napa, gates, dayco, generic, loose and tight and no change at all. I'm about to throw in the towel. Only thing I can think of is a different setup, maybe go to a driverside mount instead of passenger.

Re: Belt Help!!!!!!
 

But you said the belt doesn't fit the pulley. Good chance that's your problem. Are you not able to find one with the correct width and angle?

How does the belt fit the waterpump pulley? If it's good, you might have the right belt, but need a different pulley on the alternator.

Re: Belt Help!!!!!!
 

Whats The Number On The Belt ???

Re: Belt Help!!!!!!
 

Belt fits the water pump fine, it just seems to stick up out of the alternator pulley to much, its not flush. I tried a smaller width same problem. My next step might be a different pulley, I read someone used a Z28 deep groove pulley and that solved their problem.

Re: Belt Help!!!!!!
 

Gates XL 7315.

Re: Belt Help!!!!!!
 

Have you tried belt dressing?
You might need to go to a double belt pulley set up.

http://prestone.com/enca/node/437

Re: Belt Help!!!!!!
 

You say it is the alternator belt slipping for sure. How do you know that? Is the alternator belt slipping on the alternator or on the water pump?

I'm not saying it's not, I just would like to know how you are making that determination.

The two grooves on the water pump pulley appear to be different diameters. Are the two grooves on the crank pulley also different diameters?
If the two grooves on the crank pulley are the same diameters, both belts will be traveling at the same speed. That means that at least one belt will be slipping on the water pump pulley at all times. One belt is on the tension side of the drive pulley, the other belt is on the take-up side of the drive pulley. That can have an effect on what you're hearing and when.

There are several things that may be in play here. Pulley diameter matchup and degrees of contact on the circumference of the pulleys.
Better pictures of all the pulley positions would be helpful.

Re: Belt Help!!!!!!
 

How tight did you put it on? You should pull it tight, then slightly let up so there is a small amount of sag on the either the top or bottom, then tighten your bolt.

Re: Belt Help!!!!!!
 

I tried belt dressing and all it did was made a sticky mess. Never again. I emptied the can killing carpenter bees, so it wasn't a total loss.

Re: Belt Help!!!!!!
 

Take the belts off and fire up the truck and see if the squeal stops, then put 1 belt on and try again, then take that belt off and install the other belt..

One time i had a belt squeal that was driving me crazy trying to figure it out, it turned out that the manifold vacuum port for the tranny was left unplugged and the tranny vacuum tube was hooked to the carb, it was a vacuum leak that would whistle when the engine was revved, something to consider?

Re: Belt Help!!!!!!
 

I have not tried belt dressing yet and the belt is not super tight, I backed it off a little.

Re: Belt Help!!!!!!
 

I haven't taken both belts off yet, but when I remove the belt from the water pump to alternator, there is no more squeal.

Re: Belt Help!!!!!!
 

After looking at the water pump pulley the groove that the alternator belt is on is about 1/16 smaller then the other groove on the water pump pulley. I don't know that the belt is slipping on the alternator pulley for sure, it could be the water pump pulley. I just assumed it was the alternator pulley. As far as the crank pulley grooves go, they appear to be the same, but only one groove is being used on the crank pulley. To me it looks like the belt sits to high on the alternator pulley and isn't flush, but I put one on there that was and it still squealed. I tried to take a better pic of set up. See below.

Re: Belt Help!!!!!!
 

Loosen the belt as much as you can to see if/when it stops squealing, then gradually tighten up to where it starts squealing again. I'm guessing you know it isn't a bearing sound.

Re: Belt Help!!!!!!
 

>>but only one groove is being used on the crank pulley.<<

Want to run that past me again? Are you saying the PS belt only goes around the waterpump pulley?

Re: Belt Help!!!!!!
 

Didn't help, sloppy or tight still no change, goes away when you remove it though.

Re: Belt Help!!!!!!
 

One belt goes from crank pulley to water pump pulley to power steering pulley, the other belt goes from water pump pulley to alternator pulley. That belt does is not on the crank pulley. Only one groove is being used on crank, the first one closest to motor is not being used, it is not in line with any of the pulleys.

Re: Belt Help!!!!!!
 

That very well may be the problem, the crank pulley is probably for a short pump and I have a long and only one groove is being used powering it all.

Re: Belt Help!!!!!!
 

Unless you've got the wrong setup going, are you sure it's a 'belt' squeal and not a bearing squeal (when under pressure)?

edit due to above post: You've got bigger issues. Did you just assemble this? or, I thought you were simply replacing.

Re: Belt Help!!!!!!
 

Well I switched alternators thinking it was a bad bearing but same squeal. Even with the belt really loose and not a lot of pressure it still squeals. So IDK.

Re: Belt Help!!!!!!
 

I did not assemble this setup, trying to get it right from the person who did assemble.

Re: Belt Help!!!!!!
 

You should be able to see if it truly is straight aligned with each pulley. If it looks off, chances are it is and isn't right. You have a pass. side setup (mines driver's) so I'm not sure. From what you've posted, maybe you have the wrong water pump? or, the alternator is mounted on the wrong side. not sure

Re: Belt Help!!!!!!
 

>> the other belt goes from water pump pulley to alternator pulley. <<

That is the problem. No doubt about it.

You've got three accessories driven by the slack side of the PS belt. You have contact on around 90 degrees of the circumference of the water pump pulley to drive all three and as I said it's not on the tension side of the belt.

Re: Belt Help!!!!!!
 

Right, it doesn't touch crank at all because the first groove on the crank closest to motor is unusable because it doesn't line up at all. Only the second groove on the crank closest to radiator can be used because it lines up with first groove on water pulley and power steering. That crank pulley is probably the wrong one, for a short pump, my guess?.

Re: Belt Help!!!!!!
 

Someone correct me if I'm wrong - long water pump (mounts to pass. side) is for A/C setups, and short (driver's side mount) isn't.

Re: Belt Help!!!!!!
 

^ the above is referring to the alt. *mount placement differnce between long/short water pumps

Re: Belt Help!!!!!!
 

That pulley is waaaay too narrow for that belt....... said another way, that belt is riding waaaay too high in that pulley.

It's been said already, but get the right pulley and your problem should be solved.

http://67-72chevytrucks.com/vboard/a...1&d=1384721312

Re: Belt Help!!!!!!
 

Two different alternators have been installed; do they both have similar fitment in pulley? It looks fat in there, but so does mine, no issues here.

Re: Belt Help!!!!!!
 

Sbc went to long water pumps after 73 if i remember correctly, the same year they moved the alt to the passenger side, it has no relation to air conditioning.

While your looking make sure the other pulleys are not worn so much on the V that they have bad contact.