E46 Fanatics Forum banner
1 - 20 of 23 Posts

·
Registered
Joined
·
40 Posts
Discussion Starter · #1 ·
Some manufacturers have found that due to the mass of modern alternator armatures, sudden deceleration in engine speed can cause the drive belt to vibrate. So you will start to see more of these over-running clutch pulleys on modern cars. You will find this pulley on almost all VW diesel motors. Here is how I came to installing it on my engine.

I had begun feeling a slight vibration upon shifting at higher RPM's, and to be honest I noticed this shortly after installing my ATI crank pulley. I tried to look for reason's why. The first thing that I noticed is that the ATI crank pulley has a solid belt pulley whereas the stock pulley is isolated from the crank by the rubber bonding material. As is every other stock BMW pulley. So what I think is happening is that upon sudden deceleration the mass of the alternator is causing the belt to pile up and vibrate.

So I had my boss rev the engine to about 4500 and sure enough. As the RPM's climbed the tensioner would stretch out as the crank tugged on the belt, but once he lifted that tensioner went to town! It vibrated like crazy. So first I ordered up a new tensioner and tried that with the same results. Then I poured out the oil that was in tensioner shock and filled the shock with actual shock oil the "felt" a little thicker. Upon revving the engine again the results were slightly better but not much. Once I installed the INA alternator pulley it was smooth as glass. When the revs would some up the tensioner would stretch out like normal and once he lifted it settled back down and barely moved. Even at idle my tensioner hardly moves at all now.

Most all of the '00-'02 330's came with the Bosch 120 Amp alternator (and that is all I have tested this on), which is the same alternator used in the VW diesels. The INA part number is #022 903119C
The stock pulley weighs 9oz. and has a 50mm diameter
Turner under drive pulley weighs 1oz. and has a 58mm diameter
The INA clutch pulley weighs 18oz. and has a 56mm diameter.

Now I know that the clutch pulley is waaay heavier the the other two put together. But you still get a little of the under drive effect and it lets the alternator do it's thing. And if you want to split hairs the INA pulley is threaded so you don't need the nut, I didn't weigh it but it should buy you an ounce back.:D
There are a couple of special tools needed to do this. First being a long T50 torx socket and a splined removal socket, Baum Tools part number #3400.
Here are a couple of pics.
 

Attachments

·
Registered
Joined
·
756 Posts
fwiw the only change I noticed was extreme smoothness
interesting though...
 

·
Registered
Joined
·
1,771 Posts
few months ago my car started doing this annoying squeaky noise
thought it was the belt so replaced it and it stopped after a week it began to squeak again
got it checked out mechanic said it was my alternator. alternator pulley was a little off place , i took it to some one else he said its your alternator pulley
he said some of these cars after 100miles its known to happen? but i:dunno: is this related to the tread ?if not ignore ;)
 

·
Registered
Joined
·
40 Posts
Discussion Starter · #11 ·
Dude, you totally killed me thread...........nah I'm kidding. I can't say I have ever replaced and alternator pulley due to squeaking before, but I am not there looking at it. I have replaced a lot of belt idler and tensioner pulleys though, maybe that is what they meant?


And to reply to some comments above. The ATI damper made huge improvement is the smoothness of my engine, don't get me wrong. But if you would like to see what I talking about open your hood and have a buddy or whoever blip the gas pedal and rev your engine up to about 4k-5k, and watch your main belt tensioner pulley. I have done this with stock cars with stock camshafts and stock crank dampers and they all flutter like crazy. I am not saying that this modification needs to be done I feel it is just another step in making this a smooth driving engine. And as evidence to prove it, the next time you look at a E90 325i with the N54 engines they come with these alternator clutch pulleys stock.
 

·
Registered
Joined
·
5,669 Posts
few months ago my car started doing this annoying squeaky noise
thought it was the belt so replaced it and it stopped after a week it began to squeak again
got it checked out mechanic said it was my alternator. alternator pulley was a little off place , i took it to some one else he said its your alternator pulley
he said some of these cars after 100miles its known to happen? but i:dunno: is this related to the tread ?if not ignore ;)
Your problem most likely lies in either a bad Idler pulley or a bad Tensioner pulley. To test either, take the belt off and spin the pulleys. If you can spin them easily and they just keep spinning, then they are toast.

In order to justify a good idler or tensioner pulley they must have some resistance when spinning and should not spin freely. You'll see what a good pulley feels like when you buy one.

Alternator pulley isnt your problem, thats for sure.
 

·
Registered
Joined
·
6,931 Posts

·
Registered
Joined
·
40 Posts
Discussion Starter · #14 ·
OP,

I'm gonna give this a try, you sold me. Can anyone find a better price than $65 ?

http://www.dnlauto.com/products.asp?cat=304

EDIT: I found this on Ebay, it appears to be the same for $49.95 Shipped.
http://cgi.ebay.com/ebaymotors/NEW-...r_Truck_Parts_Accessories&hash=item4cfa27cd2f

Thanks.
All I can say is that I would only buy one manufactured by INA, the VW techs I talked to back when I was researching this said they have seen a lot of aftermarket pulleys fail.
 

·
Registered
Joined
·
6,931 Posts

·
Registered
Joined
·
1,410 Posts
First of all, bump for a really great thread!

Second of all, the price of these overrun pulleys has come down a lot. I just picked up a genuine INA pulley off ebay for $27.xx shipped. Amazon has them for $35 with prime.

There are a couple of special tools needed to do this. First being a long T50 torx socket and a splined removal socket, Baum Tools part number #3400.
Here are a couple of pics.
I've confirmed that the Bosch alternator in my 2003 330i has 12-spline's in the middle of the pulley shaft, and I believe this is true for all 330i alternators. You must have gotten a T50 torx socket to work for you though.

I found that Baum makes another version of part number 3400 called B3400 that combines the long 12-spline socket with the multispline socket that fits into the pulley.

If you want more variety there is another company making the same tool too, CTA manufacturing part number 8088.

http://www.amazon.com/CTA-Tools-8088-Alternator-Wrench/dp/B005OH0LU8

Looks like BMW uses this same overrun pulley on the e9x and other newer chassis too so there's obviously some benefit.

For me, I wonder if using the overrun pulley on the alternator will help prevent a tensioner failure that is plagued some ESS Twin screw owners. Should keep the movement of the belt very minimal.

And also, thank you for comparing the size measurements to the turner underdrive pulley kit, I found that very helpful!
 

·
Registered
Joined
·
138 Posts
Any thoughts on the relative merits of the Audi/VW pulley cited and the one used on E9x? Not sure if these links will work but here are the specs on each from INA:

https://webcat.schaeffler.com/web/s...390/keywords.xhtml?result=1553562337631&csc=1 (INA 535 0012 10 Alternator Freewheel Clutch)

https://webcat.schaeffler.com/web/s...cationSearch.xhtml?result=1553561785642&csc=1 (INA 535 0164 10 Alternator Freewheel Clutch)

I wouldn't mind going for the larger Audi unit to get the underdrive benefit, but above all I want good belt alignment.
 

·
Registered
Joined
·
1,410 Posts
I've had my INA overrun pulley on for about 3 years and 35k miles and its started to fail.

I'm getting a chirping noise on cold startups. Isolated down to this pulley.

Fortunately they are cheap ($25) and fairly easy to replace.

Other than that, things have been running great.

Any thoughts on the relative merits of the Audi/VW pulley cited and the one used on E9x? Not sure if these links will work but here are the specs on each from INA:

https://webcat.schaeffler.com/web/s...390/keywords.xhtml?result=1553562337631&csc=1 (INA 535 0012 10 Alternator Freewheel Clutch)

https://webcat.schaeffler.com/web/s...cationSearch.xhtml?result=1553561785642&csc=1 (INA 535 0164 10 Alternator Freewheel Clutch)

I wouldn't mind going for the larger Audi unit to get the underdrive benefit, but above all I want good belt alignment.
That second one has different measurements/proportions than the other unit that we've tested, I dont think it will work.
 
1 - 20 of 23 Posts
Top