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Thinking of Serpentine Belt System

2136 Views 59 Replies 20 Participants Last post by  Rufus68
I'm not thinking about adding one to my vehicle, but the setting one up on one of these classic cars.

Can someone possibly add a serpentine crankshaft pulley, a serpentine water pump pulley, and a serpentine alternator pulley onto a 289/302 and use the alternator setup to tighten the belt? Get the pulleys from an 80/90's Mustang. I see the prices for what an aftermarket serpentine system goes for, and it's a lot of cash.

Can it be done in the way I'm thinking of?
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I like this look, just have a rookie question. Is that enough wrap on the water pump pulley?
The multi rib belt has more contact area per inch of belt vs a V belt, so contact area could be equivalent. Consider a true serpentine system, the flat back of the belt drives the waterpump, so having the grooved side drive it would reduce the amount of wrap needed.
 

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Part of the 'big deal' about a serpentine setup is that you get more wrap around the pulleys compared to a normal "v-belt" routing. If you use a multi-rib flat belt with the old routing, you don't gain a thing. In fact, the V-belts 'grab' the pulleys because of the way they bunch up when you bend them sharply, allowing them to hang onto the pulleys better than a serpentine type belt in the same configuration.

The factory serpentine belt setup routes the belts through pulleys in a way that makes more of the flat belt touch the pulleys, getting more grip with less resistance. They last longer, and steal a little less power, plus your alternator won't squeal anymore.

So bottom line here: Yes, you can route a serpentine belt that way, using serpentine pulleys. But it's not the best idea. If you have an upgraded alternator, to make it not squeal, you'd have to run a lot of tension, and that may cause premature wear on your water pump and alternator.
A serpentine belt typically has 6-8 small V grooves that similarly would "bunch up" when bended.

When I went to a high output alternator I had to go from single to dual V belts to stop the squeal. Perhaps avoiding squeal is why CVF uses an 8 rib belt vs a more typical 6 rib.
 

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I'm not thinking about adding one to my vehicle, but the setting one up on one of these classic cars.

Can someone possibly add a serpentine crankshaft pulley, a serpentine water pump pulley, and a serpentine alternator pulley onto a 289/302 and use the alternator setup to tighten the belt? Get the pulleys from an 80/90's Mustang. I see the prices for what an aftermarket serpentine system goes for, and it's a lot of cash.

Can it be done in the way I'm thinking of?
I used a modified Fox Mustang serpentine, it was cheap, and mostly OEM. I used a piece of 1/2" billet aluminum to adapt the KRC power steering pump. Also used an underdrive crank pulley and WP pulley.

 

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A serpentine belt typically has 6-8 small V grooves that similarly would "bunch up" when bended.

When I went to a high output alternator I had to go to dual V belts to stop the squeal. Perhaps avoiding squeal is why CVF uses an 8 rib belt vs a more typical 6 rib.
CVF also has a line of 6 rib pulleys and belts sold under the "Spartan" label on their ebay page. kip
 

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Part of the 'big deal' about a serpentine setup is that you get more wrap around the pulleys compared to a normal "v-belt" routing. If you use a multi-rib flat belt with the old routing, you don't gain a thing. In fact, the V-belts 'grab' the pulleys because of the way they bunch up when you bend them sharply, allowing them to hang onto the pulleys better than a serpentine type belt in the same configuration.
I'll disagree with that statement. As you can see from the photo I shared in my first post in this thread, my water pump doesn't have a lot of belt wrap. I spin my motor to 7,500 on occasion. I have absolutely no belt slip. In the old days I sometimes had issues with slipping V belts in performance applications. I seriously doubt if I used a V belt on this motor I wouldn't be be dealing with slippage. As others have pointed out, there is more surface contact area on a 6 rib belt. I believe 6 rib belts might be made of a softer substance than V belts allowing better grip.
 

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CVF also has a line of 6 rib pulleys and belts sold under the "Spartan" label on their ebay page. kip
Had they had that when I bought my double V, I may have gone that route. I did not like the idea of harder to find, and more $, 8 groove belts.
 

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A serpentine belt typically has 6-8 small V grooves that similarly would "bunch up" when bended.

When I went to a high output alternator I had to go from single to dual V belts to stop the squeal. Perhaps avoiding squeal is why CVF uses an 8 rib belt vs a more typical 6 rib.
When a flat belt is on a flat surface, anything besides 'flat' (and that includes grooves and bunching) actually reduces the amount of surface area in contact with the pulleys, thus reducing surface area and friction.

When a V-Belt is in a deep "V" groove pulley, and it expands sideways as it 'wrinkles' from wrapping tightly around a curve, that forces it harder against the sides of the V of the pulley, and greatly increases grip.

The flat back of a serpentine against the flat water pump pulley actually has more friction than the 'ribbed' side against a flat pulley.

However, if the pulley is grooved, and has ribs that match the ribs on the serpentine belt, that increases surface area and friction too.
 

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When a flat belt is on a flat surface, anything besides 'flat' (and that includes grooves and bunching) actually reduces the amount of surface area in contact with the pulleys, thus reducing surface area and friction.

When a V-Belt is in a deep "V" groove pulley, and it expands sideways as it 'wrinkles' from wrapping tightly around a curve, that forces it harder against the sides of the V of the pulley, and greatly increases grip.

The flat back of a serpentine against the flat water pump pulley actually has more friction than the 'ribbed' side against a flat pulley.

However, if the pulley is grooved, and has ribs that match the ribs on the serpentine belt, that increases surface area and friction too.
I have never seen a grooved side of a multi-rib belt ride on a smooth pulley. Look at the pulleys on a serpentine setup, They all have grooves to match the belt except for the ones that ride on the back of the belt.

The contact area of a typical V belt is slightly more than 5/16" on each side of the belt, so 5/8" total. An automotive multigroove belt is atleast that before adding in the extra area afforded by the grooves.
 

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I have never seen a grooved side of a multi-rib belt ride on a smooth pulley. Look at the pulleys on a serpentine setup, They all have grooves to match the belt except for the ones that ride on the back of the belt.

The contact area of a typical V belt is slightly more than 5/16" on each side of the belt, so 5/8" total. An automotive multigroove belt is atleast that before adding in the extra area afforded by the grooves.
I haven't seen it either, but we were talking about routing the belts in odd ways and running normal rotation water pumps with serpentine pulleys, so I thought it was worth mentioning.

As you point out, there's a reason some have grooves and some don't!
 

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Discussion Starter · #37 ·
If it is only the alternator squeal of a 3G alternator you're trying to solve, then you can also change the voltage regulator to the time delay "white" voltage regulator.
Time delay voltage regulator on eBay
When it comes to the squeal, I was also thinking of a relay with a 10 second delay wired to the green/red wire coming off the alternator to a switched 12 volt source.
 

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Discussion Starter · #39 ·
That sounds complicated when they make a white voltage regulator that has the 10 second delay built in. No extra wiring required.
Why are you trying to take away my excuse for spending more time under the hood of my car? :)
 

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