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So i looked around last night on here for a few hours. I could not find a straight answer on the balance of the I5. Are they internally balanced, or externally. There seemed to be some debate on this. The crank pulley tool nub made some people say external. I think they are internally balanced motors. I have this question because i just installed a custom flywheel on my 85 4k and now have some vibration. I really would like to settle this matter. I am going to be building a stroker soon just want to add to my audi knowledge.
 

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the motors are not internally balanced. You can get them to internally balance, but the cranks will need to be drillled to lighten in some places, and welded up with mallory in others to increase the weight. Also, when the motors are balanced, they will need to have bob weights installed. It is the only inline motor I know of that requires bobweights. If you got something like a JB aluminum flywheel, they are zero balanced at the factory, so they either need to be balanced to your motors needs, or you need to have your motor internally balanced.
 

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I have the very same problem with my coupe. I made up a jig to balance the flywheels to a known configuration, the one I went for was the AAN motor. I dont think the other I5 motors are far off from that, but the factory flywheel is out about 18 grams at about 10 inches off center, mine shakes like crazy around 4k rpm...
 

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JT4k said:
My JT is internal balanced and is nice and smooth. Granted, not a billion HP but it is fine.
Where did you get that done at? I gotta get mine done soon once I get it all pulled apart to do a rebuild and whatnot.
 

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I just had mine internally balanced by C&T Machine in Orem. Orem is 40 miles south of Salt Lake. since they just did mine, they know all they need to do others. I dont know where Minden is in Nevada so I dont know if that is an option for you. they do great work and Hank(shavedquattro) will tell you the same as he has them do work for him too.
 

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Hairball II said:
I honestly don't mind running one i was just curious after I saw this guy had an aluminum crank pulley not a balancer.
http://www.s2forum.com/forum/showthread.php?t=38833" onclick="window.open(this.href);return false;
Unless you want your crankshaft to crack keep the harmonic balancer. Btw if doing an internal balance the stock one can be 0 balanced also, you're just going to loose the regular locking ability for installation and removal of the high torque bolt.
 
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