Alternator Pulleys 101: Clutch type / one-way pulleys - Page 3 - PeachParts Mercedes-Benz Forum

torsionbar · #31 11-28-2017, 06:46 PM

Quote:

Originally Posted by VT220D

I looked for a V belt decoupling pulley but I never found one. I think the decoupling pulley arrived too far into the serpentine era for a V belt version. I'd love to be proved wrong on this though!

Decoupling pulley not needed for V belts. V belts have fixed tensioners, while serpentine belts have automatic tensioners. This is why V belts will slip (by design) in certain conditions, but serpentine belts do not.

The INA clutched pulley is VW p/n 022903119C and costs $29.25 from Pelican.
The Mercedes Voltage Regulator - Bosch p/n 1197311242 costs $25.78 from the South American River.

These are correct for all om606 engines. If you have over 100k miles on your car, and you're removing the alternator anyways to change the pulley, it would be foolish to not also replace the voltage regulator with a new one, while you're in there, as the brushes wear out.

Maxbumpo · #32 12-03-2017, 06:33 PM

Quote:

Originally Posted by compu_85

Mine is an OAP. It's the one for late 606 motors, but fit fine on the 110A alternator I installed on my 603.

-J

J,

Did you have to use a different size serpentine belt with the OAP clutch? What size? I'm installing an Ina clutched pulley wheel on the stock alternator on my '87 wagon with OM603.

compu_85 · #33 12-03-2017, 07:42 PM

I used the belt specified for the 3.5. (possibly the only part on the 3.5 that's cheaper than the 3.0, since it's shared with the GM 3800 V6)

I think you'll be fine with the stock belt.

-J

Maxbumpo · #34 12-03-2017, 09:04 PM

Awesome, thanks. Really looking forward to installing this clutch. I'm planning to take a few videos and upload to youtube. The serpentine belt shock is rattling at the top mount (rubber bushing seems to be getting loose), so I've got a new shock to install as well. I plan to take a video, then first install the pulley, video, then the shock, and video.

Texasgeezer · #35 12-06-2017, 07:21 PM

To start, I found another good link to further describe these new pulley types:

http://www.gates.com/oreilly/tech_tips/GATES%20ADP%20BROCHURE.PDF

What I found today is my 95 stock alternator 90 amp does allow the newer type pulley to be installed.

I also found the alternator shaft is fairly short & only uses about 1/2 of the new pulley threads during mounting. From my rough measurement only about 3/8th's of an inch of thread is in the new pulley. About 3/8ths of the new pulley thread is unused. I plan to get a metric allen set screw to insert & hopefully secure & brace the new pulley better ( probably not necessary but I'll feel better ).

After reading the linked brochure above I was disappointed that the one way clutch pulleys don't provide near the benefit of the 'overrunning alternator decoupler' type pulley.

I checked to make sure the new pulley belt grooves matched the old pulley. Seems to be right on.

I used a pulley available from Pelican. 022 903 119 C $29.50

Pelican Parts - European Automotive Parts and Accessories - Porsche • BMW • Mercedes • Volkswagen • Audi • Saab • Volvo • MINI

If any of y'all know of a OAD type pulley that will work. Please post info.

Diseasel300 · #36 12-07-2017, 10:51 AM

I've been chasing down a very annoying moaning "woooooooo" noise from my engine area once it reaches operating temperature, driving at 25-30mph (1500-1800 RPM) and the A/C running. I've long suspected the belt is the issue, so I've tried a Gatorback (which was REALLY LOUD) and a Duralast from Vato-Zone which turned out to be the quietest, but still moans with the A/C on and the engine hot.

This thread inspired me to try a clutched alternator pulley, I've replaced everything else in the tensioner assembly and it is smooth and well-damped.

I installed the VW part and I'm very delighted to say that it completely STOPPED all the moaning "wooooooooo" noises coming from under the hood when the A/C runs and travelling at low speeds/low RPM's.

It's worth noting that I'm running the stock size 70A alternator. No idea if it's original or not, all the tags are worn off and it looks like it was sourced from the Titanic wreck, but still working well and the bearings are still smooth. It was a nightmare getting it out of the car, the bolts took a 3' cheater handle to break loose, NO IDEA why they were that tight, way beyond excessive. Once torque was broken, they unthreaded by hand with no corrosion or rust, so I can only assume they were installed by HeMan himself.

If working on an old alternator like the one my car has, be aware that the shaft is an 8mm allen instead of a 10mm XZN. A 22mm socket on a rattle-gun took the retaining bolt off without a problem. Installing the clutched pulley was easy since I had access to a long 8mm allen, but I could not find one locally at any of the auto-parts stores. Just a heads-up for anyone adding a clutched pulley to an older alternator to be prepared for an allen instead of an XZN!

Additionally my alternator had a spacer washer under the original pulley. I found it was necessary to leave it in place for the alignment to be correct with the new pulley. Not sure if that is a standard practice or not, just another FYI.

Mxfrank · #37 12-07-2017, 12:49 PM

You can probably find an overrun pulley to fit any application, but it will take some patience. You can start with this list:

http://www.ika-germany.de/wp-content/uploads/AlternatorPulleys2014.pdf

Or this site, which gives blueprints for the pulleys and decouplers offered:

https://store.alternatorparts.com/pulleys-and-clutch-pulleys.aspx

You're looking for a pulley that has the same diameter as your stock alternator. You must also match the number of grooves, offset and thread size. Note that there are several fastening systems used, so you may need to buy a tool for assembly.

Texasgeezer · #38 12-08-2017, 05:33 PM

Thanks to Fastenal I found an allen screw that would work to take up the leftover threads in the new pulley ( about 1/2 of threads unused by alternator ). I couldn't find a readily available shorter screw.

Photo shows part # & set screw. Anti-seize coated threads shows unused thread amount of new pulley. There was room left to use splined tool and allen wrench to tighten set screw. Hopefully that will better tighten & secure new pulley.

Next is to look at belt tensioner area.

Diseasel300 · #39 12-08-2017, 09:54 PM

That "set screw" will do nothing since it is not part of the alternator shaft. For all the good it's doing, you might as well shove a stick from a nearby tree in there.

The pulley tightens up on the shaft threads, it doesn't require a nut to hold it in place like the original pulley did. If anything, it is a more secure fastening since you have the pulley itself threaded onto the shaft instead of gripped by friction from the holding nut.

Texasgeezer · #40 12-09-2017, 12:12 PM

Puzzling you say that. To me it will help lock the new pulley to the alternator shaft. It will pull the new pulley against the alternator shaft threads and tension the three pieces. I'm doing it for extra assurance that the new pulley won't loosen. I don't think shoving a stick in there would serve the same purpose. It seems the alternator would have two places with tension, the contact against the alternator shaft hub and the entire thread length of about 3/4" instead of the 3/8" provided by only the alternator threads.

Also a lot of mechanics use only a light weight battery powered impact wrench to tighten. I didn't see the repairman attach my pulley and haven't trusted mechanics for about 57 years now. Too many loose connections, missing nuts & screws, overtorquing, and excessive charges "we want $1,200 to start diagnosing your idle problem" . "we're sorry your glow plug tip burnt off, dropped into your cylinder and destroyed your engine." That was with only a few miles of one cylinder hammering after they replaced an injection pump under warranty. Had it towed back to the dealer, they charged me for replacing the dirty injector. Fixed the hammer, but that cylinder blew about a 100 miles later due to the dropped glow plug tip due to the overheating of excessive fuel while hammering.
Regrettably the engine itself was out of warranty.

Diseasel300 · #41 12-09-2017, 12:36 PM

The piece you threaded into the end of the pulley is not attached to the driven shaft. It provides NO mechanical bond other than between itself and the pulley threads. It's the same concept as a shaft broken halfway through the pulley, the broken part adds no mechanical stability or advantage to the system. The only part holding the pulley in place is the area contacted between the pulley and the alternator shaft. The stub sticking out is more than adequate to hold things in place, provided it was torqued down with the proper tool.

Texasgeezer · #42 12-09-2017, 04:49 PM

To me, the splined socket tool is used to prevent the new pulley from turning as torque is applied to the allen screw. That torque results in the pulley threads putting a greater force on the alternator threads and the allen screw threads. The more torque the tighter the three pieces are together until something fails. The pulley is tighter on the alternator threads and that should help reduce the chance of loosening.

Without the further tightening after touching, I would agree with you that not much benefit is obtained.

To me it is the same principle as a jam nut, one of the most reliable methods of preventing loosening.

If I'm wrong no harm done, if I'm right then it should remain tight so I won't have an unexpected failure because it loosened.

I'm just trying to help others and definitely don't want to suggest doing things wrong.

Maxbumpo · #43 12-09-2017, 05:48 PM

I think Texasgeezer is right, this is comparable to a jam nut, but internal instead of external.

Maxbumpo · #44 12-09-2017, 05:51 PM

Quote:

Originally Posted by Diseasel300

It's worth noting that I'm running the stock size 70A alternator. No idea if it's original or not, all the tags are worn off and it looks like it was sourced from the Titanic wreck, but still working well and the bearings are still smooth. It was a nightmare getting it out of the car, the bolts took a 3' cheater handle to break loose, NO IDEA why they were that tight, way beyond excessive. Once torque was broken, they unthreaded by hand with no corrosion or rust, so I can only assume they were installed by HeMan himself.

Sounds like your alternator is original, that sounds like my experience removing the alternator on my '87 wagon first time. I think that with time there is some additional bonding that occurs.

Diseasel300 · #45 12-09-2017, 08:03 PM

Quote:

Originally Posted by Maxbumpo

I think Texasgeezer is right, this is comparable to a jam nut, but internal instead of external.

Jam nuts do not work that way. A jam nut works by literally "jamming" the threads of the original locking nut. A nut works by having a frictional contact "area" between its face and the piece it locks against. A jam nut adds an additional frictional "face" against the 2nd face of the original nut and literally creates a "jam" situation if the original nut should try to loosen or back off (hence the name "jam nut").

In the case of the clutching pulley, the inner bore of the pulley literally is the nut. It should be tightened and torqued against the hub on the alternator shaft. It is mechanically identical to the original nut that was in place, but actually has MORE threads in contact with the shaft, so actually has a better bite on it than the original setup did. The allen setscrew that was added has nothing to bear against and will eventually loosen up. Even if it remained tight, it is not providing a "jam" force against the alternator shaft, the pulley could still unthread as if it were not there.

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