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 Harmonic Dampener Question?
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SwiftITR
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134 posts [100%]
Des Moines Iowa
11-20-2015
  Harmonic Dampener Question?« » Reply  Edit


I completely understand the dangers of running a non-dampened crank pulley. I have heard the term "tuned rubber" used when describing OEM crank pulleys with built in harmonic dampening.

My question is: Is is safe to use a crank pulley from a different stroke B18 engine? Example: running an Integra LS 89mm crankshaft with an ITR crank pulley. Or are the rubber dampeners inside the pulleys "tuned" for the specific resonance frequencies of each crankshaft they were originally intended for, thus losing vibration dampening effectiveness when paired with a different crankshaft?




Mt3c
Only my opinion

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14 posts [100%]
Orange County CA
6-29-2016
 « Re: Harmonic Dampener Question? (SwiftITR)« » Reply  Edit


Disclaimer: I'm no expert in engine harmonics, but I try to use common sense where available.
You asked a very specific question, but haven't really defined your definition of "safe". Daily driven for 90,000 miles, a race season or 2 hours?

http://honda-tech.com/forums/a...22745/

Quote, originally posted by 94eg! »
ITR part is 13810-P73-J01 so it is definitely different. They probably use a smaller harmonic damper since the crank is beefier and the flywheel is lighter...

***edit: Now I remember that the ITR pulley is meant to control crank harmonics in a higher rpm range than the other pullies. I think Larry over at Endyn explained this some years ago. A rubber isolated harmonic balance can only control crank harmonics in a specific rpm window, so it's designed for the specific application. This explians all the different pullies from the different motors...

from this researched post, dampers are tuned for a rev range on a specific design. Now if you were to change a component that contributes to harmonics balance like the crank, (flywheel too?), that damper won't work as designed.


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SwiftITR
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134 posts [100%]
Des Moines Iowa
11-20-2015
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Context: I am really hoping to get 100,000 miles out of this recent motor rebuild. My Integra is used as a weekend warrior mostly, but I do daily it in the summer months sometimes. My last rebuild in July of 2004 went 90,000 miles before needing to be rebuilt last summer. That included some track time and a lot of drag racing under 20psi of boost. I am just looking to take as much stress and wear off of the bearings as possible. I am only pushing 10psi as of now. I was just curious if the rubber was specifically tuned for each type of crankshaft or if all OEM pulleys are pretty much the same, minus pulley diameter obviously. I will check out that thread on the subject. Thank You.

coolhandluke
Break on...



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13070 posts [100%]
HI
12-12-2005
 « Re: (SwiftITR)« » Reply  Edit


A new crank pulley isn't cheap, but if you are looking to achieve 100,000 miles out of your build on an ITR motor/crank, then I would play it safe. You already dropped the coin on the rebuild, so I would opt for the best solution for motor longevity.
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