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Old 07-30-2012, 06:10 PM   #1
flashmeow
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Join Date: Apr 2008
Location: Dallas, TX
Posts: 2,220
My Ride: E30-E46-E90-E90M-F30
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.

Last edited by flashmeow; 07-31-2012 at 07:08 PM.
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