Fan belt chirp,need help

heres the problem,i put a bbc in my sons pu and has a chirp when you blip the throttle.we have changed belts,water pump pully,sandblsted the pulley.pulled our hair out.This is crazy,but we can make it stop only by removing the fan.This is a motor that came from a running truck,no noise in then.The only thing we changed was using the 6 blade fan off the small block.We sure would appreciate your help.Oh this don't sound like belt squeel,more like a metallic eek.This is also the second new water pump,short one.Thank you Jack

 

Your belt is too tight. It's the bearing you hear chirping. Just back off the tension on the belt so it stops but doesn't slip.

 

Thanks Rap,tried that too.I've told my son that it will knock the bearing out .It may be that this one is bad already.

 

I would take that fan off and inspect it very carefully for cracks, loose rivets. Swap in another fan and see if it still makes the same noise.

Bob

 

Bob, we took it off last nite,tried without it no noise .Looked it over good,tapped it with a hammer,haven't found anything .Gonna try a different fan today.This has been so exasperating.Thank you guys. Jack

 

If it was the bearing it would do it all the time. It is the belt. Spray some Windex on it and see if that quiets it.
Also. check the belts in the pulleys. Be sure they aren't bottoming out in the grooves, and that they match the Vee of the pulleys. Some belts have the wrong profile and don't drive well. Many alternator pulleys have a different Vee and they will squeal.

 

How much contact does the belt have on the fan pulley? If it's less than 90 degrees the bigger fan may just take too much power for the belt to drive it. Try a different fan, what was wrong with the fan that was on the engine?

 

Good usage of a 5$ word... hahah

 

We tried the water spray,it will quiet it.Only that don't always work on it/Pretty much 90* wrap,changed the upper pully yesterday.That only helped til we put the fan back on.We changed fans when we swapped out sbc,thought the 6 blade might cool better.I wonder if that 6 blade has enuf drag to hold back just for that eek?This also happens when driving and step on it. THANK YOU Jack

 

Well the rest of em i been using are only 4 letters

 

Hold the compound-cuss words that nobody has ever heard in reserve, you might need them.

How does the belt alignment look?

Bob

 

Put the old fan back on.

Tommy

 

What brand belts do you have?

 

Is the belt the correct width? Should not sit too deep in pelley.

 

Back in the day we used to apply some stuff in a stick to the belt when it chirped.
It may have been belt dressing or Door-Ease.

 

I had a flex fan that did that once. It would chrip when you gassed on it. The blade was a little loose where it mounted. I luck up and found it when I sprayed BP baster on it. It would not chirp for a few days until the oil slung off. Needless to say, I don't run them anymore. Mabey it's something like this, mabey not?
28

 

Main bearings ???

Oldmics

 

Bolts might not be getting tight on the fan, bottoming out, running out of thread, ect. Try a washer.

 

try running a bar of soap on the inside of the belt . also if you canged spacers on fan check the bolts to see if they are rubbing on inside of pulley.

 

xxc

 

Think back to when you took it out of the original vehicle . Did it have A/C or other accesories that you are now not using? Originally it would have had multiple belts going over the water pump . Is it possible you now have changed to other mounting and adjusting brackets that are putting the alternator too high up on the arc of adjustment and not realy pulling correctly ?

 

Well we have checked bolts.not bottoming on the shoulder,not touching the pump body,put in new grade8 bolts.The alignment is really close,I made the brackets and they are stout ,really straight.Belts we have tried are napa,autozone,orielly.we have about 8 different ones.different profiles.I took some pics awhile ago,will try to post laer ,i'm going to see about a different fan now.Oh,the noise is pinpointed at about 11 oclock on the pully.Mabe if the fan change don't do it i can try a video.Bobss396,my wife says i can put more of them words in a row than she ever heard

 

It's possible that the six blade fan is harder to turn and your belt doesn't have enough "wrap" around the pulley, causing it to slip and squeal.

 

And remember,,anything (usually dailys or older land yachts) the utilize 2 belts,they have to be "matched".
Lets say your ride uses 2 belt & you go buy 2 gates belts of the same part number--say 3508.
One 3508 will be slightly different than the other 3508.
While still in the trade,I'd order 'matched sets" or,belts with the same 'lot' number.They will be exactley the same ,as they were made & cut at the same time with the same die.
If this isnt done,one of the belts will slip & make noise,,,,they wont tension the same when tightening.
2 cent special.

 

Thanks guys,icouldn't get a dofferent fan today so i guess that won't help.I am running only one belt at this time.The pulley we borrowed is a double,but one is smaller dia.We want to add air one day,but till we get thi figured that won't happen.I really appreciate all the ideas.I don't think i'll ever have another bbc.

 

What he said. There are two different belt widths and corresponding pulley widths from that era. Also, if you are using a cheap auto parts store Chinese belt, try a Gates XL. Same for a worn out belt. They can get skinny and still look OK.​

I just put up the Gates XL chart here, XL starts around page 12 -

http://members.cruzio.com/~dane/Other stuff/Gates XL Belt Size Listings.pdf

 

No more to say that's not been already said, except...

Be safe...stay out of line of the fan blade in case she lets loose...especially since there's a chance that it's faulty. It can be deadly. Good luck.

 

My corvette was making a belt noise when you hit the gas quickly....I tried about 3 belts from advance and two other auto suppliers.

Finally went down to Grainger....yes Grainger and paid a premium for a belt....problem solved.

 

I was going to say this exact same thing.

 

Now they got Edelbrock "Gasgacinch & Belt Dressing". Small with can with a WWII-style pinup girl on the label. Works pretty good as a belt dressing. Temporary, though.