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Hi,
Asking this as a general question as I truly don't know the pros and cons of changing pulley/belt setup on my engine. Currently, my 350 is an AC car with a stock clutch fan/shroud and the 3 individual belt setup. Are there any true benefits to converting to a serpentine setup and what is involved in that or is it more for an aesthetic function?
No issues with my current setup and I don't plan on messing with it if it's working and no issues, just curious.
There are no true serpentine drive setups available from the aftermarket for an Olds motor. All of them use the conventional rotation water pump with a flat multi-rib belt and a BOATLOAD of idler pulleys to force the belt into contact with the pulleys. While I haven't done any analysis or testing, my engineering experience tells me that such a design probably increases drag and resulting HP loss over the original V-belt drive. At best, there's no improvement for your $1700 or more.
The only true serpentine drive for an Olds motor was the one used on the V6 diesel from the factory. It used a reverse rotation water pump and bolts to any 64-90 Olds V8. Your chances of finding the diesel brackets are only slightly better than those of finding a zero mile W-30 for $1000. The pump itself is available from rebuilders. There are bracket kits available to mount accessories on an Olds motor with this pump. Your call if the price is worth it or not.
There are no true serpentine drive setups available from the aftermarket for an Olds motor. All of them use the conventional rotation water pump with a flat multi-rib belt and a BOATLOAD of idler pulleys to force the belt into contact with the pulleys. While I haven't done any analysis or testing, my engineering experience tells me that such a design probably increases drag and resulting HP loss over the original V-belt drive. At best, there's no improvement for your $1700 or more
Thanks Joe. Seems like the only pro would be adding extra shiny chrome under the hood and that doesn’t interest me much. Appreciate the education.
I did the conversion on my 88 Cutlass. It uses the diesel reverse rotation water pump along with chebby mid 90's truck accessories and brackets with Extreme Supreme's adapter brackets. I had all the parts except the CS alternator and Ford crank pulley. The hardest part is cutting the bracket for a mechanical fuel pump. The setup works fine, whether I gained anything, who knows.
Last edited by olds 307 and 403; Dec 30, 2019 at 05:37 AM.
Kind of my point. It's either $1700 for a bling-y aftermarket pseudo-serpentine system or several hundred bucks and fabrication labor to build your own. At the end of the day you have questionable gains (that may even be negative) and a new single-point failure (one belt instead of two or three).
What, exactly, makes that a pseudo-serpentine? I can find no definition of a serpentine belt system that would exclude them...
A true serpentine belt wraps around the crank and reverse rotation water pump pulley in an "S" shape - like a SERPENT. Hence the term. This allows over 200 deg of belt contact with each pulley, which allows the system to work with lowered belt tension and thus lower drag and HP loss. These psuedo-serp systems use a conventional pump and a bunch of idler pulleys to artificially force the belt into contact with the pulleys. Just because the system uses a flat, multi-rib belt doesn't make it a "serpentine" system. My 86 Chevy truck uses a similar flat belt to drive the A/C compressor, and nothing else. It could have just as easily been a V-belt. That doesn't make it a serpentine system - especially since all the other accessories use traditional V-belts.
A true serpentine belt wraps around the crank and reverse rotation water pump pulley in an "S" shape - like a SERPENT. Hence the term. This allows over 200 deg of belt contact with each pulley, which allows the system to work with lowered belt tension and thus lower drag and HP loss. These psuedo-serp systems use a conventional pump and a bunch of idler pulleys to artificially force the belt into contact with the pulleys. Just because the system uses a flat, multi-rib belt doesn't make it a "serpentine" system. My 86 Chevy truck uses a similar flat belt to drive the A/C compressor, and nothing else. It could have just as easily been a V-belt. That doesn't make it a serpentine system - especially since all the other accessories use traditional V-belts.
Citation needed. No definition I've found states anything with regard to the direction the water pump must turn. In fact, many serpentine systems don't drive a water pump at all. And plenty of these systems use multiple idler pulleys to get the belt to wrap sufficiently around each pulley. Since you appear to have found information to the contrary, I'd love to read it.
Citation needed. No definition I've found states anything with regard to the direction the water pump must turn. In fact, many serpentine systems don't drive a water pump at all. And plenty of these systems use multiple idler pulleys to get the belt to wrap sufficiently around each pulley. Since you appear to have found information to the contrary, I'd love to read it.
If it makes you feel better, you can go ahead and call anything with a flat multi-rib belt a "serpentine" drive. That's about as misused as "numbers matching" anyway...
For those who want more info, the flat, multi-rib belt used in serpentine (and "pserpentine") drive systems was invented by James Vance at Gates Rubber and patented in 1975. The first automotive use was by Ford on the Mustang in 1979. Note that the key discriminator in the patent is the design of the cords in the belt to keep it tracking properly when the flat backside of the belt was used to drive a flat pulley - as on a reverse rotation water pump. Here's the patent #3,911,755. Here is an illustration from the patent.
Another option instead of serpentine system.
I went with CVF under drive V-belt system. I don't have any data to support increased or decreased horsepower. I needed new pulley's anyways, so I decided to go this route. They look nice, fit real well and run great with no issues. Get the right size water pump pulley for AC or non AC.
Jeff
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From the CVF site, they claim increased horsepower decreased slippage.
Oldsmobile 350 Rocket & 455 Engines
We manufacture and sell the highest-quality V-Belt pulleys for Oldsmobile classic engines including the 350 Rocket and 455. Our pulleys are made using the exact specifications as the original equipment manufacturer to ensure a perfect fit for all 350 & 455 engines with 5.6" and 6" tall water pumps (measure before ordering). Thanks to our unique manufacturing process and design, our pulley replacements provide increased power and decreased slippage.
All CVF designed & manufactured products include our industry leading Life Time Warranty and unparalleled 1:1 customer support.
Another can of worms the under drive v belt pulleys. Not a good idea for charging or cooling. I needed a 100+ amp alternator to properly charge and my 403 definitely ran hotter with the tiny crank pulley. Look at the factory A/C or heavy duty cooling option pulleys, overdriven a lot compared to factory non A/C pulleys, which were a much larger crank pulley than the undrive pulleys and a closed impeller water pump for better cooling.
Last edited by olds 307 and 403; Dec 30, 2019 at 03:52 PM.
If it makes you feel better, you can go ahead and call anything with a flat multi-rib belt a "serpentine" drive. That's about as misused as "numbers matching" anyway...
Doesn't make me feel different either way - if everything I had ever seen/read/heard about serpentine systems was wrong, I'd quickly change my usage of it. You are just claiming something that goes against pretty much every definition of a serpentine system and I was giving you an opportunity to set the record straight. But extraordinary claims require extraordinary evidence. You aren't supplying any. The patent is great reading...for the design of the belt and some of the benefits of it over a traditional v-belt setup. But it makes no mention that the water pump must be driven nor that it must be driven with the backside of the belt.
Doesn't make me feel different either way - if everything I had ever seen/read/heard about serpentine systems was wrong, I'd quickly change my usage of it. You are just claiming something that goes against pretty much every definition of a serpentine system and I was giving you an opportunity to set the record straight. But extraordinary claims require extraordinary evidence. You aren't supplying any. The patent is great reading...for the design of the belt and some of the benefits of it over a traditional v-belt setup. But it makes no mention that the water pump must be driven nor that it must be driven with the backside of the belt.
There is no legal definition of "serpentine", but the guy who invented the flat, multi-rib belt designed it to ensure tracking when the flat backside was used Where else would you require that? Where exactly do you think the term "SERPENTine" came from???
There is no legal definition of "serpentine", but the guy who invented the flat, multi-rib belt designed it to ensure tracking when the flat backside was used Where else would you require that? Where exactly do you think the term "SERPENTine" came from???
So, again, you're making up your own definition, yes? Looking around - every resource I can find will state a serpentine system drives multiple components with a single belt with no mention of water pumps or their direction of rotation. The "serpentine" term still applies to a belt that snakes its way between multiple components. In fact, the very aftermarket system you seem to think doesn't count forms some pretty solid 'S' shapes. It also takes advantage of being able to use the backside for all of those idler pulleys - so still in line with the original patent.
I'm out. Thought I was missing something, but I'm clearly not.
There are no true serpentine drive setups available from the aftermarket for an Olds motor. All of them use the conventional rotation water pump with a flat multi-rib belt and a BOATLOAD of idler pulleys to force the belt into contact with the pulleys. While I haven't done any analysis or testing, my engineering experience tells me that such a design probably increases drag and resulting HP loss over the original V-belt drive. At best, there's no improvement for your $1700 or more.
The only true serpentine drive for an Olds motor was the one used on the V6 diesel from the factory. It used a reverse rotation water pump and bolts to any 64-90 Olds V8. Your chances of finding the diesel brackets are only slightly better than those of finding a zero mile W-30 for $1000. The pump itself is available from rebuilders. There are bracket kits available to mount accessories on an Olds motor with this pump. Your call if the price is worth it or not.
Hello Joe, did a quick search on the V6.
GM made 2 versions of this engine,. One was for rear wheel drive, and the other was front wheel drive.
And from what I found, the front wheel drive only had the serpentine system.
So my question, does the front wheel system work with the 350?
Hello Joe, did a quick search on the V6.
GM made 2 versions of this engine,. One was for rear wheel drive, and the other was front wheel drive.
And from what I found, the front wheel drive only had the serpentine system.
So my question, does the front wheel system work with the 350?
I don't know where you found that, but the photo in Post #2 is a RWD version. Both had the serpentine drive, but the accessory locations were different. The RWD version bolts to any SBO.
I don't know where you found that, but the photo in Post #2 is a RWD version. Both had the serpentine drive, but the accessory locations were different. The RWD version bolts to any SBO.
The 4.3L came in two versions. The LT6 was an all-iron engine designed for the rear-drive G-body cars (Buick Regal, Chevy Malibu and Monte Carlo, Olds Cutlass Supreme and Cutlass Calais), while the LT7 was designed for front-wheel-drive cars like the Oldsmobile Cutlass Ciera. The engines were significantly different, with the front-drive LT7 engine employing aluminum heads and a low-profile die-cast aluminum intake manifold. As a result, the LT7 was 62 lbs lighter than the LT6. The LT7 also had a serpentine belt system, so the accessory mountings were very much different that the rear-drive engine.
The 4.3L came in two versions. The LT6 was an all-iron engine designed for the rear-drive G-body cars (Buick Regal, Chevy Malibu and Monte Carlo, Olds Cutlass Supreme and Cutlass Calais), while the LT7 was designed for front-wheel-drive cars like the Oldsmobile Cutlass Ciera. The engines were significantly different, with the front-drive LT7 engine employing aluminum heads and a low-profile die-cast aluminum intake manifold. As a result, the LT7 was 62 lbs lighter than the LT6. The LT7 also had a serpentine belt system, so the accessory mountings were very much different that the rear-drive engine.
To what truth, I don't know
Once again, the fact that something is on the web doesn't make it true. Take third-party websites with a grain of salt. You'll find people on the web who say headers don't fit Supremes, also...
Read the factory Chassis Service Manual, Parts Books, and other primary source material. Better yet, scroll up and look at that photo in post #2 and believe your own eyes.
Once again, the fact that something is on the web doesn't make it true. Take third-party websites with a grain of salt. You'll find people on the web who say headers don't fit Supremes, also...
Read the factory Chassis Service Manual, Parts Books, and other primary source material. Better yet, scroll up and look at that photo in post #2 and believe your own eyes.
I had seen a couple of v6 diesels but never looked close, now I will have to
The LT6 and LT7 have the same amount of power, so must be slight mod for front wheel drive
Last edited by Kyle's77cutlass; Jan 1, 2020 at 12:47 PM.
It does use the reverse direction water pump off the awful diesels from 84. There is a company called GMB making them, and I've linked to it in the article. The best part about it is it uses GM OEM parts from an 88-92 S10 Blazer, which are very common.
Is that a stock G body A/C hose? Does it actually seal? The A/C line is slightly different on later serpentine R4 vs the stock G body connection point. The stock top rad hose WILL contact the belt. I used a 1.5" plumbing nipple and a extra piece of rad hose. What application is that hose off? I found a 6K975 belt fits quite well is close to ideal, I found a 6K950 the absolute minimum on this setup.
Last edited by olds 307 and 403; Jul 12, 2020 at 06:02 PM.
Is that a stock G body A/C hose? Does it actually seal? The A/C line is slightly different on later serpentine R4 vs the stock G body connection point. The stock top rad hose WILL contact the belt. I used a 1.5" plumbing nipple and a extra piece of rad hose. What application is that hose off? I found a 6K975 belt fits quite well is close to ideal, I found a 6K950 the absolute minimum on this setup.
If I remember correctly it's off a 70's Delta 98. I sat upstairs at the parts store for over an hour trying different combinations. Done 10,000 miles and no contact yet! The belt is definitely a bit tight. This is a 956 on there now. I will go to a 974.
ACDelco 26003X Professional Upper Molded Coolant Hose
Good to know on the application for the hose, hopefully it fits my 70S. I plan on swapping this over to my 70 Cutlass S with Sanden adapter brackets, the R4 compressors are garbage and plan on a Classic Air under dash A/C.
Good to know on the application for the hose, hopefully it fits my 70S. I plan on swapping this over to my 70 Cutlass S with Sanden adapter brackets, the R4 compressors are garbage and plan on a Classic Air under dash A/C.
Cool, I made a promo code for you. 15% off if you decide to go with it. I just made the Small Block kit better. You can now use your factory mechanical fuel pump and fan with it
Yeah, that is probably the way to go. The common available pump. Problem with the sbc brackets is the water pump. The V6 diesel reverse rotation water pump is nearly impossible to find that works with them and the adapter brackets. I was lucky to get the second to last one available from Flowkooler.
The problem with these not-really-a-serpentine aftermarket kits is that to even get close to the belt contact needed with the conventional water pump, they use multiple idlers and excessive belt tension, which increases HP loss and pretty much defeats the whole point of using a serpentine system. Factory serpentine belts with a proper reverse rotation water pump have about 270 deg of contact on the crank and water pump pulleys. Scroll up and look at the V6 diesel picture I posted in post #2. Of course, paying $1900 just to make your car less reliable (one belt breaks and you're walking home) never made a lot of sense to me. $1900 buys a lot of go-fast parts.
The problem with these not-really-a-serpentine aftermarket kits is that to even get close to the belt contact needed with the conventional water pump, they use multiple idlers and excessive belt tension, which increases HP loss and pretty much defeats the whole point of using a serpentine system. Factory serpentine belts with a proper reverse rotation water pump have about 270 deg of contact on the crank and water pump pulleys. Scroll up and look at the V6 diesel picture I posted in post #2. Of course, paying $1900 just to make your car less reliable (one belt breaks and you're walking home) never made a lot of sense to me. $1900 buys a lot of go-fast parts.
As always your right brother.. in just needing a high output alt and I don't know if they make them for these year cars (80s) I need a 350-500amp alt to support sound system and led lights and to charge 1 regular battery then another lithium battery..
the vbelt pulley isn't a issue I think it's that aftermarket places like mechman don't make alts for older cars
Oldsmobile produced engines with alternators mounted on both the passenger and driver side of the car. If you get the right brackets and ditch the AC you can run dual alternators.
As always your right brother.. in just needing a high output alt and I don't know if they make them for these year cars (80s) I need a 350-500amp alt to support sound system and led lights and to charge 1 regular battery then another lithium battery..
the vbelt pulley isn't a issue I think it's that aftermarket places like mechman don't make alts for older cars
Here ya go. 350 amp alternator that bolts to the 12SI brackets. I don't know anything about this vendor, but here's at least one option to an insanely expensive serpentine kit. Given the popularity of 12SI alternators, I bet there are a lot of high-amp options that bolt to the same brackets. This alternator is also available with dual groove V-belt pulleys.
Oldsmobile produced engines with alternators mounted on both the passenger and driver side of the car. If you get the right brackets and ditch the AC you can run dual alternators.
