Serpentine Belt Squeal

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Ricks70Duster340

Ricks70Duster340

My "Blue Bondo Baby"!
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I recently converted to a serpentine (8 groove) setup by CVFRacing on my 440 w/AC and PS. One belt goes from the crank pulley to the alternator and the other goes around everything else. I found a pulley misalignment in the PS pump mounting so fixed that. I am using a shroud & 6 blade Deraile mechanical fan without clutch to ensure maximum low speed cooling. When I bought the radiator (ECP) I got their dual electric fan setup but I can't use it because of insufficient clearance between the fans and the serpentine pulleys. Problem is when the engine really starts to pull around 4000 RPM I hear the dreaded screech. The belts are tight and the alignments look good now. Am at a loss why it still screeches. Edit: now wondering if the mech fan is putting too much load on the belt causing the problem?
 
I use a CVF serpentine system on my small block. I’m also using a mechanical Mopar 5 blade fan with a non thermal clutch. Never experienced any cooling issues or belt squeal with this setup so I’d definitely recommend running a fan clutch if you have room.
 
Here is a picture of the belt routing. No auto tensioner but a turnbuckle setup to set tension for each belt.

Serpentine Belt Routing.jpg
 
Cal Tonsley said:
I use a CVF serpentine system on my small block. I’m also using a mechanical Mopar 5 blade fan with a non thermal clutch. Never experienced any cooling issues or belt squeal with this setup so I’d definitely recommend running a fan clutch if you have room.
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I am certainly not opposed to putting in a clutch fan setup (I have one already). Do you run PS and AC with your CVF setup?
 
Ricks70Duster340 said:
Here is a picture of the belt routing. No auto tensioner but a turnbuckle setup to set tension for each belt.

Serpentine Belt Routing.jpg
Click to expand...

You have about as much WRAP around the water pump pully as a V belt setup so that's probably not the issue. Have you tried more tension?

does it do it sitting still in the driveway at 4K?

If so get a water squirt bottle and with it at RPM and screeching spray water on each pulley between the belt and the pulley on the infeed side one at a time. That will typically isolate the issue to one accessory, MIGHT not be your water pump pulley

My daughters Jeep ( totally stock 5.2) has a squeak in the drive pulley system. We tried a few things and finally changed the belt to a "Gaterback" belt and the squeak went away. BUT there is a big difference with a squeak ( air trapped in the V's of the pully) and squelching (belt slipping)


You could always go back to a V belt!
 
Dana67Dart said:
View attachment 1716402770


Did you order the Mechanical fan option with your kit?

I don't know what it includes

https://support.cvfracing.com/hc/en...8819-Can-I-Use-A-Mechanical-Fan-with-CVF-Kits
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I did not order the mech fan option. I will contact them about this and see what they say. I originally had the V belt setup but there was a slight misalignment I could not correct that caused the PS belt to fly off. Thought a totally new setup would alleviate that. Yes, no more thrown belts but the squeal! Will report back what I find from CVF.
 
That system only has a little over a 1/4 wrap on the power steering and the water pump. Ran into the same issue with a similar set up
 
yea not much wrap on the crank too ,
not sure if possible alt/waterpump one belt p/s ac on other
 
The only pulley with too little wrap is the PS. Add an idler between the PS and AC.
 
toolmanmike said:
Probably the issue. Unbolt the fan and bolt the pulley back up and test it without the blade on.
Click to expand...
Will do. Would a clutch fan setup reduce the drag enough you think? Getting a bit tired of pulling the radiator every time I mess with this setup!!!
 

Contacted CVF and this is their response:

Thank you for reaching out to us,

You do not need a special pulley to run a mechanical fan. As long as the pilot sticks through the pulley and still indexes with the fan or spacer you are good to go.
 
Ricks70Duster340 said:
Did you find a solution?
Click to expand...

It was some time ago on a Big Block truck. I know we moved the AC under the alternator. We started looking at different systems and moving things around. Having an auto store owned by a relative left me have several different length belts. We also changed some pulleys.

Always make sure your spinning things i the correct direction like your water pump and accessories.

Your lucky today you have the internet to look at different set ups. You may end up buying one that's better engineered. I don't see a reason for the AC unit on top .

I would say its the power steering squealing. Get a shorter belt and eliminate the AC for a trial. You'll get more wrap and I'll bet your squeal goes away.
 
Oldmanmopar said:
I would say its the power steering squealing. Get a shorter belt and eliminate the AC for a trial. You'll get more wrap and I'll bet your squeal goes away.
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I'm not too good at estimating sizes; can you venture a guess at what size belt I should try... or how to measure for it myself?
 
Ricks70Duster340 said:
Contacted CVF and this is their response:

Thank you for reaching out to us,

You do not need a special pulley to run a mechanical fan. As long as the pilot sticks through the pulley and still indexes with the fan or spacer you are good to go.
Click to expand...
How can they say that when right on their web site it says you need something? I think you got hold of someone with their head up their butt.
 
Add an idler. Home Depot 1/8x1 inch strip, drill, bench vise, hammer, hack saw. Spacer can be an oversize nut. Space as needed for alignment.

Squeelin Rick.png
 
Update: I originally had the squeal when I had a mechanical fan mounted directly on the water pump hub. I then had a new Hayden fan clutch & fan so tried that. Same result. My son had a worn out fan clutch & 7 blade fan that I put on. No squeal, we're onto something. Apparently the mechanical fan had enough drag that caused the belt to squeal no matter how tight it was. I am using the ECP radiator and originally bought it with electric fans. The fans stuck out too far and hit the AC compressor so contacted ECP. They no longer sell those fans but a newer SPAL style that are much thinner, so got those 3600 CFM (1800 each) fans mounted to a new shroud. My car is a 72 Challenger so had to shave the lower passenger, bottom corner so it would fit then redrill the shroud mounting hole. Had to initially do the same to the radiator mount as well. Used the same harness as was originally installed. Everything went together well and the squeal is gone.

Side note: when I was using the mech fan setup the engine temp stayed right on 180* (my thermostat temp) while driving above 30 MPH. The engine would only start to run hot while idling in traffic. With the electric fans the engine temp runs at 190* while driving above 30 MPH. This tells me that the electric fan shroud is actually inhibiting airflow. At idle the fans now keep the engine running around 195* with the AC on, which is acceptable to me. Hope fully this info helps someone who may be in the same situation I was in.
 
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