Dual belt drive system or serpentine?


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By 58F600 - 5 Months Ago
Anyone running a 140amp alternator and Sanden SD709 or similar set up? Both of these are a decent load and I have my doubts I'll have long term success with the V belts. But I'm not finding any serpentine set ups. Yes I have reasons to run both of these vs the smaller lower power consuming versions.

Pictures of any dual belt set ups appreciated, or serpentine systems.
By 55blacktie - 5 Months Ago
I could be wrong, but I think the primary reason automobile manufacturers switched to serpentine belts was due to an effort to extract every mpg from their vehicles. I highly doubt that ease of maintenance or longevity was their primary concern, considering how complicated modern vehicles have become. Their dealers wouldn't be very happy, if the vehicles were more user-friendly when it comes to servicing and repairs. 

My first vehicle that was equipped with a serpentine belt was my 1988 Mustang 5.0. I have nothing against serpentine belts, but I've never had to remove a pulley and bead-blast it to eliminate squeaks on any vehicle that I owned that used v-belts. I don't have deep pockets either.   
By DryLakesRacer - 5 Months Ago
I used the Vintage Air AC/Alternator front mount. The Compressor is a Sanden and the Powermaster Alternator is a 100 Amp. The AC unit is an Old Air Products Hurricane electronic unit. 
With every electric device turned on I have: headlights on high beam, radio, AC, (fan on high) electric wipers, backup lights, my load is 34 Amps. I do not have a  massive radio with power amps or bass banging ear splitting speakers. The AC will freeze you out on medium fan. 
I have 3 pulleys. The alternator is the only one going around the water pump and crank.The PS and AC compressor each have their own belt off the crank. In 4 years there in no slippage or noise from any belt 
When the AC is turned on the RPM drops 25. These compressor don’t have the loaded draw as the ones of the past… Good luck. 
By Hoosier Hurricane - 5 Months Ago
This may not be relevant, but back in the '80s I was working at a GM dealership, in the parts department.  A pickup was towed into the shop.  It had died on the road, and the roadside  diagnosis was a locked-up engine.  It was under warranty, so the mechanic started removing the engine.  When he took the serpentine belt off, he noticed  that the alternator was locked up.  He thought, maybe he should  see if the engine was really locked up, so he hit the key and the truck started  instantly and ran without issue.  I could not believe a serpentine belt could stall a V-8 engine, but it did.  So I  guess F600 could benefit  if he could adapt a serpentine to his truck. 
By 58F600 - 5 Months Ago
DryLakesRacer (6/16/2024)
I used the Vintage Air AC/Alternator front mount. The Compressor is a Sanden and the Powermaster Alternator is a 100 Amp. The AC unit is an Old Air Products Hurricane electronic unit. 
With every electric device turned on I have: headlights on high beam, radio, AC, (fan on high) electric wipers, backup lights, my load is 34 Amps. I do not have a  massive radio with power amps or bass banging ear splitting speakers. The AC will freeze you out on medium fan. 
I have 3 pulleys. The alternator is the only one going around the water pump and crank.The PS and AC compressor each have their own belt off the crank. In 4 years there in no slippage or noise from any belt 
When the AC is turned on the RPM drops 25. These compressor don’t have the loaded draw as the ones of the past… Good luck. 




That's what I was looking to start with. The Vintage Air Brackets. But we are adding EFI, electric fans, electric fuel pump, dual A/C, power inverter etc etc. The electric fans are always a big draw thus the bigger alternator. I've installed a bunch of power master stuff and had issues with their bigger units chipping a single V belt when they switch on at start up, all the manufactures I looked up also said single V belt wasn't recommended over 90amps load. I don't think we will be there continuously, but certainly will see peaks in that range. You know how a belt gets once it slips!

I thought about the double V belt going around Crank, Wp, alt and compressor, but you lose a ton of belt wrap on everything and I don't think that would gain much. With the serpentine set up a couple idlers quickly fixes any wrap issues.

I looked at the commercially available kit on the market and it won't work for us as the alternator sits where the Turbo is going to live. The Vintage Air bracket would be perfect.
By 58F600 - 5 Months Ago
All American won't sell any pulleys outside the complete kit. This is why I have a machine shop lol
By DryLakesRacer - 5 Months Ago
My wife’s 85 Pontiac Grand Am died in an intersection near our home. With help it was pushed to the side of the road,then towed home and backed into our garage. when I got home to check it out it was locked up.. The first thing I did was use the spring tensioner and remove the serpentine belt…. You guessed it the alternator was locked up. Those spring tensioners put a hell of a load on bearings. I had a 6202 sealed bearing in my stash and had the job done in about 1 hour.

58F600.. I don’t like electric fans and did every thing I could to solve any over heating before the AC and alternator were added. With the help of guys here a lot of irritating things were fixed. Without PS I could have easily used a dual belt system. Since my typical driving daytime with the AC  on and the current load under 20 I don’t foresee anything popping up. 
By 58F600 - 5 Months Ago
Probably overkill going with the CS144 alternator, but being that this is dump truck, constant low speed operation with all the electronics is going to pretty normal I'm afraid. With a carb set up we could probably get away with it, but the EFI units start getting problematic with low voltage in my experience. Its usually not an all the time issue, but an annoying issue that pops up rolling up to stop signs and such with a/c on, engine fan on etc. . While the 12si 140 amp and CS144 140amp are rated the same, the cs144 will have almost double the amperage at idle that I think will be a nice preventative measure. Chart attached for those researching this in the future. The smallest alternator pulley I can find is 2.125. So with the 6.5" crank pulley, It should put me right at 1700rpm at the alternator shaft at idle. That would be 45amps on a 12si, or 95amp on the CS144.

I ordered the Vintage Air brackets and will have to slightly modify them for the wider spacing on the CS144 vs the 10/12si the bracket was designed for. 

Thanks for all the feedback! Our first test for all this is Oregon to Tennessee via the Trans American Trail. I'll be sure to update how things work and see if I can get any amp load data for those considering a similar package for the restomod type truck like ours!
By KULTULZ - 5 Months Ago
All American won't sell any pulleys outside the complete kit. This is why I have a machine shop lol


If a 'KIT MAKER' will not sell service parts, what are you going to do, buy another complete kit because of a single component failure?
By 58F600 - 4 Months Ago
I agree. Not very comforting. I've used March, Vintage Air and Holley on other stuff and no issues buying a single part.