the crank shaft its harmonic balance?

theART

6 pages and all it takes is a 5 second google, 3.43min of pure fun

SDOF Resonance Vibration Test - YouTube

It may not fail in 50k, but it sure wont last 200k. Since I generally don't keep cars for longer than 3 years, I would definitely use this mod myself, let the next owner worry about it.

luigi90210

when he starts using the blow torch on it and right before he breaks the seal

XwChriswX

Yeah, I see it now. There are two videos separate, I thought he meant in the same video.

When it loaded for me, the video filled the screen, I didn't see there were 2 separate videos on the same page.

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Bonnie - Stage 2, Audio build coming this fall!
R.I.P. Abby 3/29/10 - 3/30/14

XwChriswX

But these video's just show the bolts are hard as hell to get off, they don't explain anything as to what happened, or as to the nature of the installation. These alone should not be used as ammunition against getting a pulley installed because they don't answer any questions.

For the sake of those video's, I know better what brands of pneumatic impact wrench not to buy vs anything against pulleys.

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Bonnie - Stage 2, Audio build coming this fall!
R.I.P. Abby 3/29/10 - 3/30/14

luigi90210

while i agree with you(not enough information was provided about those installs, for all we know they might have been installed incorrectly), i think the videos are showing the metals fusing together

i know its hard to undo certain bolts on an engine but to do all that is a bit much imo

XwChriswX

How do you know they've fused together though? They don't show anything removed...

Perhaps the installer just seriously over-torqued the pulley nut...

A better camera angle would be showing the gap between the pulley and the block to where you can see the fuse point.

Those video's clearly show something wrong, but like it was previously said, just using the pulley is a scapegoat is a premature diagnosis...

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Bonnie - Stage 2, Audio build coming this fall!
R.I.P. Abby 3/29/10 - 3/30/14

luigi90210

i dont know which is why i said i think

no need to attack me, i personally wouldnt install an underdrive pulley on my car but i wouldnt talk down someone who did

to each their own is how the saying goes

Trilitheum

I can explain why they get stuck together, they are not fusing. It is a galvanic cell which produces a layer of aluminum oxide on the inner diameter of the pulley.

The aluminum will corrode preferentially to the carbon steel shaft. The problem comes in the volume change when aluminum goes from Al to Al203 (aluminum oxide) the volume increase is about 2 fold.

So if the parts are in intimate contact when they were installed, the oxide layer when formed takes up additional volume and squeezes the inner shaft as it tries to expand with virtually no gap (except the machining tolerance) which is taken up quickly.

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2011 Nissan 370Z Touring/Sport, 6MT, KAD

XwChriswX

I was not attacking you, good sir.



I just hope no one takes those videos as clear "evidence" against pulleys because they show nothing.

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Bonnie - Stage 2, Audio build coming this fall!
R.I.P. Abby 3/29/10 - 3/30/14

Huck

I'm still enjoying this conversation, and I'll throw this out there. I had to use a breaker bar with a 3 foot extension to get my stock pulley off. Sometimes it's just a pain in the ***


Sent from my iPizzle using magic and new-fangled science stuff

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wstar

Exactly. Everything I do is "because racecar". I just bought a new house and most of my decision criteria was "because racecar" (now I have more room to work on it - 3 car garage for nothing but the Z + parts + tools, unrestricted area for building further additions and testing loud racecar things).

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7AT Track Car!
Journal thread / Car setup details