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82-T/A [At Work]
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JUN 04, 03:12 PM
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Hey guys, I'm curious if anyone knows whether or not there is an existing GM application where an overrun / decoupler pulley was used on a GM CS130 alternator? I'm not really finding one, but I'd like to upgrade to one on my daughter's Iron Duke engine.
If you don't know what an Overrun / Decoupler pulley is, you can watch this video:
There's two kinds... one that de-couples during engine deceleration, and another that is spring loaded and basically absorbs the overwhelming majority of accessory belt fluctuations. There's a general warning that if your car was designed for a specific pulley OAD or OAP pulley, you must use at least the minimum (can't down-grade). But upgrading is something that is highly desired and recommended when possible.
Most vehicles come with these stock now... but unfortunately, most manufacturers upgraded the alternators at the same time they added the pulley.
Anyone know if there are ANY C130-based alternators in the GM line-up that uses one of these pulleys?
I wish I had one for my 2002 Crown Victoria LX-P74. In the shift from 1st to 2nd, the belt squeals. It was like this from the factory. The car only has like 55k miles on it, and even though I replaced the tensioner and belt (just for the sillies), it still does that. It started when Ford upgraded the 4.6 SOHC to a "Performance Improver" cyl heads (same ones on the Mustang GT from the year prior) in 2001. So it's like... "a thing" for 2001-2002 Crown Vics, which they upgraded the alternator for the next year (2003) to resolve that problem.
Would love to know if there's something I can just pop on or even if I need to disassemble two C130 alternators and make a Fiero compatible one by swapping out the stator. I would love to have one.
It dramatically improves idle/vibration, reduces strain on all the components, and is genuinely all-around better for the engine... you can see the difference here between an OAP and a solid pulley:
[This message has been edited by 82-T/A [At Work] (edited 06-04-2024).]
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Patrick
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JUN 04, 04:46 PM
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82-T/A [At Work]
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JUN 04, 07:12 PM
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Lol, I even posted the same videos.
Oh well. I knew less about them then, but I still want one.
I just bought one that I "think" will fit (pulley)... it's an OAP, and even comes with the installation tool. So, we'll see.
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82-T/A [At Work]
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JUN 05, 07:11 AM
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Just to add to this, the decoupler pulley (OAP) that I purchased has the same thread and stator shaft diameter as the factory pulley. It's also a 6-groove. SO, my thought is that it SHOULD fit. It was fairly cheap, only $35 shipped. They're usually much more expensive than that (generally around $80), so hopefully it fits.
Biggest gain I think I'll get from it is that it can help eliminate certain belt slipping situations since it has "give" that prevents jarring belt movement. I don't expect any horsepower gains (that's not what it's for), but should it fit, it will smooth out the accessory belt system, which comes with a whole host of relatively modest benefits... such as smoother idle, better off-idle initial acceleration, etc.
The caveat of course, it is a wear-item. But if you aren't driving your Fiero as a daily driver... and only drive it a few thousand miles a year... it'll last the "life of the car" as they say...[This message has been edited by 82-T/A [At Work] (edited 06-05-2024).]
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OldGuyinaGT
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JUN 06, 11:11 PM
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From 82-T/A [At Work]:
| quote | | I just bought one that I "think" will fit (pulley)... it's an OAP, and even comes with the installation tool. |
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If you find one that fits, please post the part information and source. I'm very interested! Some others may be too.
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82-T/A [At Work]
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JUN 07, 07:33 AM
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| quote | Originally posted by OldGuyinaGT:
From 82-T/A [At Work]:
If you find one that fits, please post the part information and source. I'm very interested! Some others may be too. |
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Will do... I might get lucky. The stator shaft diameter and thread need to be the same, and assuming the pulley lines up (which is more likely than not likely), it should just work.
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82-T/A [At Work]
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JUN 07, 10:11 AM
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It came today! Really fast too...
I'll see if I can get it installed today... just to see if it fits.
It did NOT come with the installation tool, unfortunately. It feels like it was taken out of the packaging, because it's on the picture.
But I should be able to at least fit it and see if it lines up with the factory pulley.
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82-T/A [At Work]
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JUN 07, 03:03 PM
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Ok, so I just went out to the garage and tried to test fit it on the alternator. I also ran some other checks too.
This is a CS130 alternator w/ 6-groove pulley (for a 4-cyl Fiero, not the 5-groove for the V6).
The OAP in question is one made by Liton, and distributed by Dayco. No point in my trying to share the part number yet, because it didn't work.
Now, the shaft size of the stator was a perfect fit on this OAP pulley. The problem however is that the threads were off. On the Dayco, the threads are integrated into the pulley, as they are for basically all OAD / OAP pullies. The one for the normal pulley has a nut and crush washer that's installed with an impact wrench.
This pulley COULD be used; however, it would need the threaded area to be drilled and tapped to the same threaded area as the alternator.
Other than this, the pulley alignment was off by ~2mm. Which is something that could be VERY simply fixed by merely placing it on a belt sander for a few seconds, or installing a pair of 2mm thick washers on the alternator to set it back slightly. You can see that here:
Another thing that I was curious about... and looking for opinions. The OAP weighs about 1 pound more than the stock pulley (which weighs only about 3/4ths of a pound. You can see that here:
Why this concerns me is that an additional 1-lb on the rotational mass can actually affect horsepower... at least that's my thought. So, I'm interested to hear what you guys think of this.
The ONLY other thing I'll add is that the OAP pulley had a slightly larger diameter than the stock pulley... so if I'm playing this out in my head properly... that would mean that you'd likely end up with a type of underdrive pulley (if you will). Would the car still charge as it should? I think so... the difference isn't so significant, but it would certainly reduce the absolute rotational speed of the alternator. It would also give you more surface area for the belt to adhere to... so, in addition to reducing belt slippage, it would... further reduce belt slippage, lol...
This one was about $35. They're normally $100... but this one was on clearance... so I'll keep my eyes out, or take it to a machine shop and see if I can have it modified.
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82-T/A [At Work]
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JUN 07, 04:20 PM
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I'm still trying to do some more research on what might fit... rather than just buying a bunch of OAD/OAP pulleys. I discovered there's a newer replacement alternator to our CS130D, which is the AD230. They have ones that will directly fit our cars... for example, same form factor as the CS130D and fits 87-88 4 cyl Fieros without modification:
(for sale): https://www.ebay.com/itm/285325370239
Of course, worth mentioning that it has a completely different connector.... a 4-pin instead of the 2-pin that we have for our alternators. The AD230 alternator has supposedly significantly better cooling than the CS130D (which itself is significantly better than the original alternators most Fieros came with. The pin-out is for a bunch of features, not all of which we need, and most of the newer PowerMaster versions of the AD230 alternators do not require any of those pins to even be used (and will still charge without them). It allows for a digital regulator that communicates with the ECM (from what I can tell), if you choose to use that feature. Personally, the CS130D is a really nice upgrade, and it seems not worth the hassle to get the AD230 unless you really just want to be weird and add additional difficulty (or are running a turbo or higher RPMs, etc.).
Anyway, I tried looking it up because I wanted to see if any of these alternators actually had OADs / OAPs offered with them, because that would likely mean they could be swapped over and I would just need to get a replacement pulley FOR that car. I totally struck out though.
Going to look at my older thread, as I remember someone saying their [swapped] engine had one.
EDIT: Blacktree said he thinks the newer 3800s have them... time to check out some newer 3800-powered cars on Rock Auto.
EDIT #2: Bingo!!! I found a part number for an OAD on a 2008 Pontiac Grand Prix w/ 3800: https://www.rockauto.com/en...info.php?pk=15593941
... found cheap on Amazon (just ordered one): https://www.amazon.com/dp/B09GZ5J27Q
... and the tool to install it: https://www.amazon.com/Sock...nator/dp/B07KV1S8T8/
Worth a try... I'll let you know when I get it and if it fits.[This message has been edited by 82-T/A [At Work] (edited 06-07-2024).]
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Patrick
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JUN 07, 05:59 PM
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