Overrun / Decoupler (Page 2/2)
82-T/A [At Work] JUN 07, 06:14 PM

quote
Originally posted by Patrick:

I assume the alternator you're planning to use has a hex hole in the end of the shaft to accommodate an Allen wrench? (...when using the tool for installing the decoupler pulley.)

CLICK FOR FULL SIZE





Yes, it does. It seems all the new ones do (CS130D maybe?)... but I was able to put the original pulley on with an impact gun. I'd ordered a new alternator CS130D from I think a 1988 Fiero V6... but of course that's only a 5-groove, so I had to remove that pulley to install the 5-groove pulley that I had that came with the CS130D alternator that came with the 88 2.5 Fiero engine I had. Of course, the mounting points for the V6 and the 87-88 4cyl alternators are different. The 84-86 alternators are the same attachment points as the V6s...

It was SOLID when I used an impact gun. My guess is that I can reinstall it with an impact gun as well. Hand-screw it on, and then use the impact gun with the little tool.
Patrick JUN 07, 06:50 PM

quote
Originally posted by 82-T/A [At Work]:

It was SOLID when I used an impact gun. My guess is that I can reinstall it with an impact gun as well. Hand-screw it on, and then use the impact gun with the little tool.



Is it even necessary to use an impact gun to tighten the decoupler pulley? I wouldn't. I'd just use the tool along with a box-end and Allen wrench. After all, the force the belt puts on the pulley actually tightens it onto the shaft.
82-T/A [At Work] JUN 07, 07:10 PM

quote
Originally posted by Patrick:

Is it even necessary to use an impact gun to tighten the decoupler pulley? I wouldn't. I'd just use the tool along with a box-end and Allen wrench. After all, the force the belt puts on the pulley actually tightens it onto the shaft.




You're probably right about that... but it's easier for me to use the impact gun regardless. I just won't go crazy with it. Or I should say... my daughter won't.

But I did bust off that pulley while they were busy shopping.


What are your thoughts on the increased weight? And possibly... the increased diameter of the pulley?

[This message has been edited by 82-T/A [At Work] (edited 06-07-2024).]

Patrick JUN 07, 07:23 PM

The increased weight isn't ideal, but it's probably insignificant in the grand scope of things. The increased diameter slows the alternator down a bit, but this shouldn't affect the charging rate (at idle) of a CS or newer style alternator. As long as the belt is long enough to accommodate a larger pulley, there shouldn't be any issue IMO.
theogre JUN 08, 01:44 AM
This "Advance" pulley won't help you for "Idle problem" & more & no car companies have use this because wear out faster + multiple costs to use it. Example: If wears out under vehicle warranty then have to eat the part & more costs @ car co & @ dealers.

You Do Not want a Bigger Alt pulley. It does same crap as "power pulley" that slows the alt often causing power problems. see https://web.archive.org/web...fierocave/csalt2.htm

Your Fiero has 12SI.
Later Fiero uses CS130 & way different then CS130D not just that have 1 fan = less cooling & often less power because of that & other reasons.
Upgrade older Fiero & more to CS130 & other versions are common, covered here & cave @ https://web.archive.org/web...~fierocave/cs130.htm

⚠️ Warning: CS130 & other newer versions HATE Impact tools putting on the Pulley. That can & often does pull the center out of the rotor. Even hand tools can do same when oven torque the nut. If the center move even a little, expect rear bearing problems now or soon.


quote
Originally posted by Patrick:
The increased weight isn't ideal, but it's probably insignificant in the grand scope of things. The increased diameter slows the alternator down a bit, but this shouldn't affect the charging rate (at idle) of a CS or newer style alternator. As long as the belt is long enough to accommodate a larger pulley, there shouldn't be any issue IMO.

Alternator Total weight means nothing for most vehicles. Only matter to GM et al faking results for CAFE for EPA etc. IOW counting every gram trimming total weight for a car to keep EPA Happy.

12SI have more total mass vs CS130 have a rotor ~ same size but CS130 has less Clearance between Rotor & Stator & other changes to make more power from less total weight @ same RPM.
CS130 vs CS130D shares same rotor diameter & maybe mass of that part but nothing else.

Example: Many claim CS130 uses thinner lighter wires on the stator = weak part = 100% crap. This claim is 100% made by Fools that Know < Nothing. CS series & others like it have the Stator wired in Delta format that doesn't need heavy wires that SI w/ wires in Y format w/ no Neutral. (SOME old Ford & other "High Amp" alt's have stator in Y but with a Neutral requiring extra Diodes for DC output.)

Delta vs Y w/ or w/o a Neutral matters to any 3 phase AC alternator/generator that vehicles have since early 1960's some even before that when stops using DC Generators. Use Web Search but doubt any here understand the papers covering the difference. I doubt even know why alt's in cars was near impossible before that.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

Patrick JUN 08, 02:36 AM

quote
Originally posted by theogre:

Alternator Total weight means nothing for most vehicles.



You've misunderstood the question and my response. Todd was asking me about the weight (the spinning mass) of the decoupler pulley compared to the original pulley... not of the whole alternator.
1985 Fiero GT JUN 08, 06:04 AM

quote
Originally posted by theogre:


You Do Not want a Bigger Alt pulley. It does same crap as "power pulley" that slows the alt often causing power problems.




Don't worry about the slight underdrive pulley effect, using a cs130 alternator with a full blown actual underdrive pulley still generates more amps across the board then my original (65 amp) alternator according to the ogre's own data as discussed (briefly) Here. Having a slight diameter difference (not as much as an underdrive pulley) will be comparable or still better than the larger capacity original alternators.

You can calculate the underdrive amount by finding the circumference of original vs new, if new is 25% larger, it is a 25% underdrive, 25% is the standard power pulley size, if it is 10-20%, it should be fine.
82-T/A [At Work] JUN 09, 04:32 PM

quote
Originally posted by 1985 Fiero GT:


Don't worry about the slight underdrive pulley effect, using a cs130 alternator with a full blown actual underdrive pulley still generates more amps across the board then my original (65 amp) alternator according to the ogre's own data as discussed (briefly) Here. Having a slight diameter difference (not as much as an underdrive pulley) will be comparable or still better than the larger capacity original alternators.

You can calculate the underdrive amount by finding the circumference of original vs new, if new is 25% larger, it is a 25% underdrive, 25% is the standard power pulley size, if it is 10-20%, it should be fine.




This is a good point. I'll test out the new one when it comes in and compare them using my caliper to determine the underdrive percentage.

Thanks!
82-T/A [At Work] JUN 29, 11:31 AM

quote
Originally posted by Patrick:

I didn't quite understand where exactly the threaded portion on the decoupler pulley was... until I saw the following images for the 3800 pulley. It appears the threaded part on one end of the decoupler pulley takes the place of the nut that's normally used to hold on a Fiero alternator pulley. It'll be interesting to see if you can make this work. It could end up being an option for 2.8 Fieros as well.





Ok, so I just tried it out this afternoon, finally got some time... and here are the results ... it's a perfect fit!!!

I bought this one: https://www.amazon.com/dp/B09GZ5J27Q

Basically... it works with the CS130/D alternator. I removed the factory pulley, and this threaded right on like it belongs. Here are some pictures:







So here are a couple of things (more pictures):





The good news is that the pulley is the exact same size as the OEM 87-88 Iron Duke alternator pulley. They are IDENTICAL.

The slightly bad news is that the alignment is off... meaning that the grooves don't line up when installed. I realize the Iron Duke isn't a high precision machine, and I could probably run it this way, but it looks like I would need a 1/8th inch washer to go between the pulley and the alternator fan shroud. This is OK because the pulley is meant to tighten down against the fan shroud, and that's what prevents the fan from spinning freely (so it's supposed to be tight against it).

I'll look for a washer that matches the interior diameter of the pulley shaft, and just go with that, so I don't have any imbalance. And of course, I'll measure properly... but just eye-balling, it looks like it's 1/8th of an inch.

The nice thing about it too is that it'll maybe stick out half an inch, so it won't interfere with the firewall or anything.


My guess is that this will work with the V6 also. The only thing is, the V6 Fiero uses a 5-groove pulley, not a 6-groove. I assume you can use a 5-groove belt on a 6-groove pulley, but I'm not sure I'd want to do that. But for the 87-88 Fieros, this would be a direct fit.


You need this tool (which is like 9 bucks):
82-T/A [At Work] JUN 29, 03:45 PM
It was right in front of me, and I didn't realize. The "crush washer" from the original pulley is the exact size and spacing that I needed to offset the new decoupler pulley... so I installed that:




It also works really well because it "catches" on the fan blade, and the base of the decoupler pulley (the part it should be fixed to), and it works perfect. I can spin by hand back and forth really quickly and I can clearly see it decoupling in one direction and catching (slowly) in the other. Pretty sweet... so... it's installed. My daughter will be pissed because she'll want to do it, but I couldn't wait.