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So I just checked on my engine, sitting here on the stand. Assuming the BC stroker crank uses the same depth as an OEM crank, the Nord-Lock washer should work. I can tighten the pulley down, even without a washer.
 

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Pro xfercase destroyer
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Seems to me it could've just as easily been a mistake in forgetting to torque the bolt to the proper spec. I mean, you thought that your engine builder red Loctited it in place, and it clearly wasn't. Are you absolutely CERTAIN that the bolt was torqued to spec? You torqued it yourself? People do make mistakes from time to time...
 

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Yes absolutely, If you have a modified high RPM motor and/or a Fluidampr. If your motor is largely stock and hasn't been touched in >60,000 miles then probably not.

Checking the torque is a 20 minute job at most. It would be a 10 minute added task if you have the car on stands to rotate your tires, replace the pads, change the oil etc.
Just want to throw this out there.. Torquing the bolt on the crank while the engine is in the car wont allow you to hold the flywheel or keep the engine from turning. Also cranking on that bolt could possibly damage the bearings while the engine is in the car so re torquing the bolt may not be the best solution.

Clay
 

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Just want to throw this out there.. Torquing the bolt on the crank while the engine is in the car wont allow you to hold the flywheel or keep the engine from turning. Also cranking on that bolt could possibly damage the bearings while the engine is in the car so re torquing the bolt may not be the best solution.

Clay
You can throw it out there, But it's going to get thrown back... :D :ROFLMAO:
 

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Just want to throw this out there.. Torquing the bolt on the crank while the engine is in the car wont allow you to hold the flywheel or keep the engine from turning. Also cranking on that bolt could possibly damage the bearings while the engine is in the car so re torquing the bolt may not be the best solution.

Clay
They make a tool for holding the crank still via crank pulley with engine both in and out of car - it makes no difference, and no wont damage the bearings.
 

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They make a tool for holding the crank still via crank pulley with engine both in and out of car - it makes no difference, and no wont damage the bearings.
cool, CWIC's comment scared me! I used oohnoo's crank pulley tool.
 

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Discussion Starter #49
Or you can make your own tool, if its off already.
 

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Discussion Starter #50
Does anybody know the OEM thread pitch for the M14 crank pulley bolt? I got a replacement bolt and it looks to be a different pitch.
 

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Discussion Starter #52
It's 1.5mm
Many thanks! I need to run a tap inside to clean up the first couple of threads and didn't want to risk wrecking it with one of the wrong pitch.
 

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Discussion Starter #53
I had some time to start pulling stuff of the side of the motor to prep for a new timing belt and found this. All 4 bolts had backed out of the alternator. One was missing completely 3 we backed out but trapped in place. This is weird and suggests there is an undamped vibration. I find it hard to believe that all 4 bolts backed out in the few seconds after the crank bolt backed out and the Fluidampr came off. To me it seems more likely that something is either generating a high frequency vibration that backed out all 4 alternator bolts and the crank bolt. This is very troubling because it would suggest that the Fluidampr isn'
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t doing its job.
 

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1994 Mit 3000gt VR4 6spd
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everything is this thread has pointed to other unknown problems like i stated before..
 

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Discussion Starter #55
everything is this thread has pointed to other unknown problems like i stated before..
Agreed but the data logs show nothing at all. It was running great, no unusual noises or vibrations and very strong output. The only variable that I can identify, was the addition of a Fluidampr.
 

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I believe the Fluidampr was installed and torqued correctly. Its the unsupported cross-section of damper, under the bolt head that's the issue. It took me a while to figure out that it was unsupported by design,
Its a horrible compromise, which reduces manufacturing cost and steps, but creates what is effectively a sprung section under the bolt head - which is never a good idea.
This compromise is why the torque spec is 130 lb.ft, which is far in excess of what's expected to secure a drive flange. I believe that the reason it was set so high by Mitsubishi, is to pre-load the unsupported cross-section of damper underneath the bolt head.
Its sprung section that compromises the pully drive flange's ability to resist axial harmonic loads. It can deflect under the bolt and loosen it.
It turns out that the OEM damper does occasionally suffer the same kind of failure. I found it documented and there are posts in this forum from the 2000's. It sees to work but could be limited to OEM RPMs.
Now that I better understand the design issues, I could see that axial harmonic loads in the higher RPMs that I'm now running, could overwhelm the pre-load in the unsupported cross section of damper.
My plan so far, is to replace the OEM load washer with a Nord-Lock rated for 130 lb.ft and which can absorb 0.7mm of axial expansion. Then I will add checking it to my routine maintenance schedule.

IMPORTANT NOTE: all of the above is about axial harmonic loads. The damper is primarily designed to manage radial harmonic vibrations, which is seems to do an excellent job of doing.
Just curious, why not call fluidampr and see what they say. Maybe you're on to something.
 

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Discussion Starter #57
Just curious, why not call fluidampr and see what they say. Maybe you're on to something.
Good point! I will do just that on Tuesday.
 

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1994 Mit 3000gt VR4 6spd
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Lol leave it to pimprn to give that horrible advice, 200 dampers and your the one with this problem and at a lower power level and barley any miles. Don't blame the damper blame your builder or whatever is going on with your car. So many people love to blame parts in this platform.
 

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Discussion Starter #59
Lol leave it to pimprn to give that horrible advice, 200 dampers and your the one with this problem and at a lower power level and barley any miles. Don't blame the damper blame your builder or whatever is going on with your car. So many people love to blame parts in this platform.
I think you are misunderstanding me. Nowhere have I stated that the Fuidampr is the problem.
My build is for track days and will probably see extended running at the top of the RPM range. I dont want it to come off again.
I have ~3000 miles on this motor, which is where issues start to show up.
I have been and remain critical of Mitsubishi's design for the end of crank assembly because its compromised.
My point in conacting Fluidampr is to see if they have any thoughts or suggestions.
My point is starting this threat is to share experiences.
 

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1994 Mit 3000gt VR4 6spd
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I understand what your saying but i'm pretty sure 99% of the people that see the title of the thread and read a couple of the first post see it as a "fluidampr problem thread". But either way good luck and hope you get it sorted out.
 
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