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Old 09-28-2010, 06:08 PM   #11
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Quote:
Originally Posted by insite
okay, this is driving me nuts. what would drive a harmonic in this engine that the DMF could actually balance out?

what i'm getting at is that this is a flat 6. it has inherent mechanical balance of 1st and 2nd order. further, the CG stays constant about the crank. the rocking couple of each bank is balanced by the other bank. harmonic balancer or no, this simply shouldn't happen w/ this configuration.

there could be some torsional harmonics, but the 1st order torsional (due to the engine pulses) is inherent to engines in general, since they create torque. IMO, this is just as well damped by a sprung clutch than by a DMF.

finally, the DMF is at the wrong end of the crank to really damp any higher order harmonics that may appear......


HMMMMMM: Jake - did the broken X51 crank come from a car with a solid clutch disk, or a sprung clutch disk?
If I remember it was from a LWF flywheel, tho I don't remember if it was a sprung disc or not.

I played it safe when I built my motor, and I have a dampened crank pulley on a dynamically balanced engine with a LWF and sprung disc.
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