Serpentine Belt Squeal

[duzie]

I have a Ford 302 with the "March Performance Polished Billet Pulleys installed. The belt is driving an Alternator, Water Pump and Power Steering Pump. I only had 350 miles on the belt when it started squealing. I replaced the belt with a new belt and the squeal on acceleration still occurs. All accessories installed seem to be turning freely. Any suggestions?

[65 Cobra Dude]

Duzie,

Sounds like an alignment problem to me. Have you checked to make sure all the pulleys are aligned?

Henry

[rich grsc]

need a picture of how the belt is routed. you just may have to run it a bit tighter

[CraigS]

Guideline-on the belt's longest run grab it w/ thumb and forefinger. You should be able to twist it 90 degrees. If you can go more tighten it.

[NAZ]

Worked on and designed belt drives for many industrial and automotive applications and belt squeal is always caused by slipping. Most common causes I've encountered: 1. too loose, 2. driven equipment seizing (you've already eliminated this as a suspect), 3. poor design (not enough wrap on the driven pulley or belt too narrow for power transfer required), 4. belt badly worn, 5. incorrect routing (serpentine systems).

Be sure you are not mistaking a bearing noise for "belt squeal".

[wareaglescott]

Was the belt you replaced frayed on the edges? Might show a slight misalignment.

[rich grsc]

Worked on and designed belt drives for many industrial and automotive applications and belt squeal is always caused by slipping. Most common causes I've encountered: 1. too loose, 2. driven equipment seizing (you've already eliminated this as a suspect), 3. poor design (not enough wrap on the driven pulley or belt too narrow for power transfer required), 4. belt badly worn, 5. incorrect routing (serpentine systems).

Be sure you are not mistaking a bearing noise for "belt squeal".

Shouldn't that be the drive pulley? I find that people always look at the accessories pulleys, not taking into account the the drive pulley(the crank) has to provide all the power for everything else. If you don't have enough belt wrap at the crank, that's where it'll slip.

[NAZ]

Thank you Rich, good catch. Yes usually the drive pulley is the first to slip as the driven is typically larger. I should have listed both drive and driven as in some cases (think over driven systems) the driven is smaller and the first to slip.

[TexasAviator]

I have the identical setup as the op. It needs to get more bite by rerouting the belt over the crank and under the waterpump. I have it in the "V" config and I hear it slipping sometimes.

[TexasAviator]

V config can allow slipping at the crank, mine does it only on initial opening of the thermostat then immediately goes away. My belt is 57.3 inches from gates.
index2.jpg


This is the proper routing from march. Unknown belt length.
index.jpg

[duzie]

I would like to thank all that have provided suggestions and questions to my problem. The old belt did not have any indication of wear. The belt is routed as the second example displayed. My concern is the water pump is driven from the back side (flat side) of the belt. I have not identified which pulley the belt is slipping at, I just assumed it was the water pump. Pulley alignment looks perfect. Is there a belt that might have a softer material that would grip better?

[CraigS]

I know it is somewhat counter intuitive, but there are millions of cars on the road where some accessories are driven by the smooth side of the belt. Works fine as long as there is plenty of wrap as in the picture.

[Ray]

Just a question and I didn’t see it in the previous replies. Have you removed the belt and run the motor to conform that it’s the belt? Pulules May turn freely by hand but have bearings that are going south on you. Another way to check would be to run the motor and spray a little (and mean little) bit of WD-40 etc on each pulley, one at a time to see if 1 stops squealing.

Good luck.

Ray

[AZREALTOR]

I put a March Pulley system on a small block in my 56 Chevy pickup last year. It would slip and squeal incessantly when i turned the A/C on. It came down to the recommended belt that March sent with the kit was too long even though the part number was the belt they use with the kit. I put on a shorter belt. No more problem. As an aside, the power steering pulley on my system is slightly out of alignment and there is no adjustment for it. So far in the year I've driven it there doesn't seem to be an issue but it's uncomfortable knowing that it is that way.

[TexasAviator]

AZREALTOR, I ended up buying a pulley installer for my march kit, i used a impact gun to get the pulley to line up. It was only 30 bucks made by Evertough kit number 67010. I bought a gates 5060573 57.3 inch belt. This was the way recommended by March.

[Crawleyscobra]

I too have a March setup and fought this problem on and off for years. A quick diagnostic for a serpentine belt is to spray water on the belt close to the squeal. If the squeal gets worst the belt is a little loose, if it goes away it is not aligned. My issue was alignment and I had to "adjust" the standoff heights. I finally got the belt running straight. I also highly recommend using a Goodyear Gator Back belt.

[AC Bill]

In spite of the smooth surface on the w/pump pulley, and the smooth side of the belt, a water pump in good condition will create very little resistance. You should be able to spin it around quite freely by hand. Unless the belt is very loose, I doubt that is the culprit.

[JRD56]

I had a belt squeaking issue on my 302. I noticed it mostly during start-up. I did two things to correct it. Well, really three things. First was to ensure the pulley alignments were correct. I found my power steering pulley was a bit out of alignment, which I corrected with some shims. Second and probably the biggest help was to increase the belt tension. But, I still had just a slight squeal so I replaced the belt with an "Elite Poly V belt" with Quite Channel Technology made by Continental. I believe Continental bought the old Goodyear Gator-back belt line. These belts have groves cut across the belt which apparently helps with squeals. All is good on my car now. Good luck.

[Avalanche325]

Funny. I have my belt off right now because of a squeal. P/S was slipping. Cleaned the pulleys up, and putting a new belt on.
They seem to go 5000 miles for me before they get noisy. I guess I should re-check my alignment.