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-   -   Information on Harmonic Damper -Crankshaft Pulley (http://forum.e46fanatics.com/showthread.php?t=936066)

flashmeow 07-30-2012 06:10 PM

Information on Harmonic Damper -Crankshaft Pulley
I recently ordered a harmonic Damper / Crankshaft Pulley and found a few interesting things that I want to share between OE (genuine BMW), OEM and an aftermaket dampers.

OE (Original BMW)

key points:

It has the drill balancing pits on the top of the pulley (three dots)

It has a few markings on the cast metal such as "MO XX" (XX=some number) and a few other marks that were stamped into the metal. Lets just call this marking the "stamps" for the duration of this thread.
On the rubber piece, damper material has the BMW part number and a few specification such as:

275-305Hz this is the frequency that the damper is design to dampen harmonics)

BMW 1123-7513862 (this is the BMW part number)

WPM and a few other digits (don't know what this mean)



Shot at 2012-07-30

Alright...lets move on to OEM (Corteco)

Corteco is the Original Equipment Supplier that makes the BMW Dampers.

On the Corteco there are the same markings found on the orginal factor/OE damper. The only two difference are:
1) there is a Corteco logo printed on the cast metal
2) the rubber damper material had the BMW part number scratched off

However...when you turn the damper around you can see the same exact marking as the Original BMW. Again, this is no surprise because Corteco makes the harmonic damper for BMW.

In this picture you can see the "MO XX" marking and the stamp marking and of course the red corteco logo.



The OEM damper has the same alignment/balancing pits on top of the pulley. the number of pits would depend how unblance the pulley came off the assembly line. the pits just makes the pulley spin in a perfect/balance circle (just like balancing a wheel)

In this picture you can see the BMW part number being scratched off from the rubber damping material

Shot at 2012-07-30

FEBI (aftermarket)

Febi is an extremely high quality/reputable aftermarket brand. Pelican Parts and other online part store stock Febi and highly recommend them.

The only differences between the Febi vs OE/OEM are:
1)balancing pits is on the side of the pulley and not on the top
2)no marking on the rubber dampening material

this picture shows the same "MO XX" marking as the OE and OEM and also the stamp marking. you can also see the balancing pits on the side and the lack of any markings on the rubber dampening material.

just like the Corteco damper, when you flipped the harmonic damper around you will see the same marking as the OE one such as the operating frequency (275-305Hz, the BMW Part Number and the WPM/other marking)



so what does this all mean?

1) I am no expert but I am guessing Febi either distribute the Corteco Harmonic Damper and brand/claim it as their own or Febi uses the same components as Corteco to make their damper.

2) You can save your money and go with the Corteco ($277) or Febi ($175). The cheapest OE/Geniune BMW Harmonic Damper can be found at $410. They usually go up to $600 at the dealership.

I hope this helps. If anyone wants to photoshop my pictures to highlight the differences/similarities then feel free.

Steven747 07-30-2012 06:18 PM

thanks for the writeup

Zell 07-30-2012 06:24 PM

Good writeup, excellent work. No one really talks about the harmonic damper around here, glad you took the initiative. There is another aftermarket damper that covers a wider range of frequencies that is very good, but it is very expensive.

cyberkaa 07-30-2012 06:38 PM

Nice investigation.

P.S. Hz, not MHz. Huge difference.

Zell 07-30-2012 06:41 PM


Originally Posted by cyberkaa (Post 14614652)
Nice investigation.

P.S. Hz, not MHz. Huge difference.

Except for a factor of 1,000,000 ;)

Okay I'll stop being a smartass.

flashmeow 07-30-2012 06:46 PM

Thanks...for the correction. I should of known better

Sent from my PC36100 using Bimmer App

MJLavelle 07-31-2012 01:13 AM

It is not a big surprise that the outer metal part is the same. Why make a mold of the part, when there is someone tho had already done all of the mold design and metallurgy for you? I am assuming that Corteco has the rights to the mold and to sell the parts to anyone they want. The same goes for the manufacturer of the rubber section. For Febi, it makes no economic sense to try to re-invent the wheel. That "MO" number is the part number for the mold itself.
But good deceive work on your part.
I have been wondering if I should replace my damper soon. It is often forgotten that this is a wear item. It is an expensive part, and I would hate to replace it too soon.
Have you installed yours, and if so, did you notice any difference at all? What did your old one look like? Pics would be great.

Bimmerguy82 07-31-2012 05:43 AM

How do you know when its bad or worn out?

flashmeow 07-31-2012 09:24 AM


trizzuth 07-31-2012 10:41 AM

I was gonna say.. why the heck did you need to replace this?

Sweetness 07-31-2012 12:56 PM

Well, I have been trying to find things about this bad boy for a long time, and it seems like no one messes with them because they are expensive and should never need replaced. I might replace mine, because I have a feeling when it goes bad, the engine makes weird noises from the bay.

Grande D 07-31-2012 01:04 PM

There has been tons of information posted relating the failure of the part. Flashtwosix- thank you for the comparison!

Sweetness- you aren't looking hard enough first off, and second of all the 323 and 325 have way less harmonic issues than the 330.

Sweetness 07-31-2012 02:40 PM


Originally Posted by zhp43867 (Post 14616477)
There has been tons of information posted relating the failure of the part. Flashtwosix- thank you for the comparison!

Sweetness- you aren't looking hard enough first off, and second of all the 323 and 325 have way less harmonic issues than the 330.

hmm. Wondering If my galloping noise is because of this.

flashmeow 07-31-2012 06:45 PM

I edited the original picture to show the photo captions

What is the main difference between the Pre 2002 and Post 2002 Harmonic Damper?

People been saying that the Post 2002 Harmonic Damper has a different harmonic dampening frequencies than the Pre 2002. However, upon inspecting the Pre and Post 2002 dampers I saw that they both have the same 275-305Hz Freq



The main difference I see is that the post AUG 2002 has the 3 ribbed AC Pulley and the pre AUG 2002 has a 4 ribbed AC Pulley
post AUG 2002 Pulley (3 ribbed) part number is 11-23-7-513-862
Pre AUG 2002 Pulley (4 ribbed) part number is 11-23-1-438-995


flashmeow 07-31-2012 07:06 PM


Originally Posted by Bimmerguy82 (Post 14615658)
How do you know when its bad or worn out?

Great question. I will try to address this tonight. My main laptop died and I am waiting for the parts to arrive so I can fix it. In the mean time I am using a backup laptop and cell phone to post to e46. It is hard wo all my saved bookmarks and photos.

The conventional wisdom is.that u can see the rubber dampening material getting distorted. However, all the used dampers I saw to include 3 brand new one (x2 febi, 1 corteco) have the "distorted" look. I guess this is part of the pressing process when the manufacturer try to install the crank pulley into the AC pulley and the rubber material just get twisted in the process.

So I am not sure how u can tell visually beside hearing any noise or seeing the pulley spinning not evenly.
Let me try to see if I can pull the pix from my broken laptop

Sent from my PC36100 using Bimmer App

here are some pix and post from the forum stating the tell tale sign of a worn dampers:


Originally Posted by Fair (Post 13274342)
http://vorshlag.smugmug.com/Projects.../DSC2451-S.jpg http://vorshlag.smugmug.com/Projects.../DSC2454-S.jpg

After our M54 motor popped (twice) I went and bought a 2005 330 rollover car, with a running motor, which we're stealing the drivetrain from now. Got the front end peeled off to where we can see the OEM balancer (which we had planned on keeping for a short while, awaiting a real balancer to be built), and...


The OEM balancer has slipped. This is a motor in a plain jane 330 automatic, with 60K miles, from a 2005 model car. And its junk. Thanks, BMW. :thumbdwn:


Meanwhile, my ultimate E46 motor solution is in progress on another E46 we have. :4ngie:



Originally Posted by McSpeed (Post 13279851)
So if the rubber damping ring looks ok in the back, but uneven in the front, that's a bad damper, correct?:




Originally Posted by Luky (Post 13409984)
So based on the picture in post #105 I should assume that my vibration damper is bad too?

(Using a long piece of flexible 1" PVC tubing as a "stethoscope" I believe that it is the idler pulley that is making the squealing noise.)

Here are the Pix of the distorted look.




what does this mean? This either mean that my Post and Pre 2002 Dampers and Three BRAND NEW Dampers are all defective or the distorted look is normal due to the pressing process of installing the pulley/dampening material.

Grande D 08-02-2012 08:52 AM

So flashtwosix, how hard is it to install one of these (not the ATI- a stock one). Any unusual tools needed?

Mango 08-02-2012 09:35 AM


flashmeow 08-02-2012 12:28 PM


Originally Posted by zhp43867 (Post 14621824)
So flashtwosix, how hard is it to install one of these (not the ATI- a stock one). Any unusual tools needed?

to be honest...I was very timid about replacing my damper because I thought there would be special tools required and I thought the process would be complicated. However, after talking to aggie...he mentioned that it would be easy so I gave it a shot.

Yes...special tools are required but there are way around this. When I fix my laptop I can try to pull the pictures and show you.

this is 5 min job. of course...I had the engine out so it was easier but the same procedure is used even if the engine is still inside the car.

step 1:
lock your fly wheel but inserting a bmw flywheel lockpin. I used a long bolt. I wrapped a bunch of tape around the bolt so that I wont marr (spelling) or damage the flywheel.

Step2: next...insert in a 21 or 22mm (will verify later) socket and use a large cheater bar to remove the damper screw. a very large cheater bar is required because the nut is TORQUED at whopping 300-305ft/lbs of force.

installing the damper is fool proof because there is an alignment tab on the damper. there is no way you can mess this up. just slide in the new damper. no pressing is involve at all. lock the flywheel and torque the new damper to 300-305ft/lbs

flashmeow 08-02-2012 12:33 PM


Originally Posted by E46Mango (Post 14621899)

thanks for the url. that member is amazing. I always enjoy reading his threads because I would learn so much from them. his pictures and decriptions are always helpful.

flashmeow 08-02-2012 12:37 PM

here is an alternative method


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