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Wed Aug 16, 2006 9:04 am

The subject heading says it all. What do you folks think? Are the benefits (if any) worth the high cost? To me........................NAH!!!!! But hey! I'm a Geezer. :P

Wed Aug 16, 2006 10:02 am

Why make something simple complex? What's the advantage?

Wed Aug 16, 2006 10:04 am

Some like them, but I don't see the point.

Wed Aug 16, 2006 10:44 am

The main reason to use a serpentine belt is to reduce drag on the motor from the pulleys. With the myriad accessories (ps, ac, etc) on modern cars, a single belt is more efficient, has less clutter and less drag on the motor.

The downside is if the belt breaks - everything is out since its just one belt.

I cannot see any advantage on a VW AC engine assuming you have accessories (AC).

Wed Aug 16, 2006 11:50 am

It looks like something for people who want looks. Why introduce another pulley into the mix (the tensioner). It adds another point for something to go wrong. Get a nice stock size degree pulley for the crank, a stock cad plated alternator pulley, and 10 shims. Put it together and you have a reliable belt system. A properly tensioned V belt won't slip and will last a long time.

Wed Aug 16, 2006 12:55 pm

NOVA Ghia Owner wrote: The main reason to use a serpentine belt is to reduce drag on the motor from the pulleys.

Question: how would this be accomplished by adding an extra pulley? The serpentine systems I've seen always seem to have an idler/tensioner pulley.

It'd seem to me that if one did install a serpantine belt system, belt changes would be more difficult to accomplish, thanks to said tensioner pulley. Plus, what are the odds of quickly finding the correct replacement belt at a Napa, Kragen, Schucks, or Auto Zone? You'd have to know the exact dimensions (since it's a custom application), and hope for the best.

Granted, if you are running A/C and power steering (in addition to your generator or alternator), a serpantine belt might be the only solution. However, who runs power steering? And having the A/C on its own belt can be a blessing in disguise - if its belt breaks, or the compressor clutch locks up or loses a bearing, you can make it home without the help of a tow truck. Stuff to think about.

In my opinion, on a vintage VW, the serpantine belt system is all show and not much go, and a step backwards in functionality and convenience.

Wed Aug 16, 2006 1:26 pm

i guess a real question is why would all modern cars have switched to serps............? i know, multiple accesory drive right? i dunno, back then one belt broke you lost one thing, now one belt all things shutdown.........

I think they are less vibration and less rotating mass ( the belt i mean) and less drag because multiple V's with smaller load on each "V" maybe?

Wed Aug 16, 2006 1:42 pm

I think it has nothing to do with efficiency. I think a single serpentine belt system is just cheaper than multiple belts. It's also a good deal easier (quicker) to change when the tensioner is spring-loaded.

Ask yourself why cars haven't had oil-bath air cleaners for many years. Same answer: money.

Max

Wed Aug 16, 2006 2:13 pm

Serpentine belts do have their place. I changed one two weekends ago, on a friend's Audi 90CS. This vehicle has a V-6, and one serpentine belt goes around the crank pulley, power steering pump pulley, A/C compressor pulley, alternator pulley, an idler pulley, and a tensioner pulley. It's the simplest solution for that application, so I like it.

Now on the other hand, back in the crazy 70's, my folks had a (new) AMC Pacer "X" (Dad bought it after a long bender; he traded in a perfectly good 1965 Dodge Coronet with 440 for that Piece o' Poo Pacer, grrr). That car had six (count 'em: SIX!) belts for the accessories. They were well nigh impossible to tension correctly and must have sapped lots of HP in friction alone. Whenever one would snap, it'd shred several others. Prime example of bad engineering thinking in action. The car was sold quickly and quietly in favor of a new Toyota soon after.

Wed Aug 16, 2006 2:19 pm

Serpentine Belts are easy to find. Here are all of the cross-referecend P/N's for the BMD system.

Napa part# 25 050365
Gates part# K050365
Dayco part# 5050365
Goodyear part# 4050365
Armormark part# 365K5
AC Delco part# 5K365.

Wed Aug 16, 2006 2:28 pm

retrowagen wrote: Serpentine belts do have their place. I changed one two weekends ago, on a friend's Audi 90CS. This vehicle has a V-6, and one serpentine belt goes around the crank pulley, power steering pump pulley, A/C compressor pulley, alternator pulley, an idler pulley, and a tensioner pulley. It's the simplest solution for that application, so I like it.

Now on the other hand, back in the crazy 70's, my folks had a (new) AMC Pacer "X" (Dad bought it after a long bender; he traded in a perfectly good 1965 Dodge Coronet with 440 for that Piece o' Poo Pacer, grrr). That car had six (count 'em: SIX!) belts for the accessories. They were well nigh impossible to tension correctly and must have sapped lots of HP in friction alone. Whenever one would snap, it'd shred several others. Prime example of bad engineering thinking in action. The car was sold quickly and quietly in favor of a new Toyota soon after.

My 1996 Mazda Protege was the same way. There were three belts, and the first time I ever changed them it took me an entire Saturday afternoon. They were layered in the engine, so I had a learning curve. I would have much preferred a serpentine belt in that thing.

If I were running A/C in a VW then I would convert to a serpentine belt and carry a spare.

Wed Aug 16, 2006 4:44 pm

Sure, I am partial,,But the main advantage, at least for ours BMD is belt retention, When Chris first got his bug a few years back he lost his belt and lost the engine as a result. After rebuilding the engine he spent a year working on the design of our pulleys,
The hold up to high RPM..even when Jason hit the wall during the Pinks race the belt stayed on,,,,
There is less vibration and no shims to adjust constantly.
The looks are secondary to function.
Kelly
www.bmdpulleys.com

Wed Aug 16, 2006 4:47 pm

C.P. Lane wrote: Sure, I am partial,,But the main advantage, at least for ours BMD is belt retention, When Chris first got his bug a few years back he lost his belt and lost the engine as a result. After rebuilding the engine he spent a year working on the design of our pulleys,
The hold up to high RPM..even when Jason hit the wall during the Pinks race the belt stayed on,,,,
There is less vibration and no shims to adjust constantly.
The looks are secondary to function.
Kelly
www.bmdpulleys.com

Does the BMD have some sort of spring tensioner? Or does it adjust by loosening that mounting bolt and sliding the idler puller?

Wed Aug 16, 2006 4:55 pm

It is not a spring tensioner so you can adjust the tension and maintain it where you want it, Some people , depending upon weather and driving like the tension a bit diffe3rently. Because it is a serpentine belt it does not need to be as tight as the V-belts.
kelly

Thu Aug 17, 2006 6:33 am

retrowagen wrote: NOVA Ghia Owner wrote: The main reason to use a serpentine belt is to reduce drag on the motor from the pulleys.

Question: how would this be accomplished by adding an extra pulley?

The flat belt on flat pulleys has less friction (resistance) than a v-belt in a groove.
But I think the reason most people would purchase them is for looks.
You won't find one on my Ghia.

Thu Aug 17, 2006 6:50 am

C.P. Lane wrote: When Chris first got his bug a few years back he lost his belt and lost the engine as a result.
That has nothing to do with a serpentine or V-belt, and everything to do with not paying attention when driving. How would driving with a broke n serpentine belt deliver a different result?

In addition: statistically, how many OEM VW V-belts come off in collisions? Furthermore, if you've had a collision, do you really care if your fan belt is still on?

I'm not a technical luddite, but I'm a firm believer in horses for courses. A huge part of the appeal of an ACVW are the technical anachronisms, and living with them. From a technlogy perspective, a properly engineered serp belt system would be superior. By the same token, I've got an extra set of Porsche Big Red brakes with 13" rotors that would make my ghia stop like nobody's business, but I wouldn't install them out of principle.

Thu Aug 17, 2006 6:53 am

thom wrote: C.P. Lane wrote: When Chris first got his bug a few years back he lost his belt and lost the engine as a result.
That has nothing to do with a serpentine or V-belt, and everything to do with not paying attention when driving. How would driving with a broke n serpentine belt deliver a different result?

In addition: statistically, how many OEM VW V-belts come off in collisions? Furthermore, if you've had a collision, do you really care if your fan belt is still on?

I'm not a technical luddite, but I'm a firm believer in horses for courses. A huge part of the appeal of an ACVW are the technical anachronisms, and living with them. From a technlogy perspective, a properly engineered serp belt system would be superior. By the same token, I've got an extra set of Porsche Big Red brakes with 13" rotors that would make my ghia stop like nobody's business, but I wouldn't install them out of principle.

I don't have principles. Send those big red's & 13's my way.

Thu Aug 17, 2006 7:30 am

Ozzie wrote: retrowagen wrote: NOVA Ghia Owner wrote: The main reason to use a serpentine belt is to reduce drag on the motor from the pulleys.

Question: how would this be accomplished by adding an extra pulley?

The flat belt on flat pulleys has less friction (resistance) than a v-belt in a groove.
But I think the reason most people would purchase them is for looks.
You won't find one on my Ghia.

Have you ever seen an actual serpentine belt? They have grooves in them, which act like a series of V's in the V belt. If serpentine belts weren't as good as V-belts, then every car on the road would be using V-belts to this day. Also, any belt, whether is be a V-belt or a serpentine belt, will slip as it ages/wears.

Thu Aug 17, 2006 7:39 am

Icy wrote: Have you ever seen an actual serpentine belt?

Uh, yeah. My blown single-cab.

The "v" creates a lot of friction as it slides along the sides of the shiv (sheave) as it rotates. Friction = resistance & heat. Less effecient.

Thu Aug 17, 2006 8:04 am

No shims = Less maintenance