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MPI Supercharger Pulley Failure

Now I have PROOF!

This is absolutely NOT an installation error !

Just got the tensioner block removed from the engine and I found the original Nyloc nut that had fallen off triggering this whole mess.

Photos to come in a moment!
 
WRONG LENGTH BOLT

After removing the belt tenisoner asmbly from Christophers nytro I found the
the bolt going through the pully to be 1.5 to 2.0mm to short and did NOT enguage the nylon ring , he was lucky it stayed on as long as it did..
 
The is the pulley sitting flat with the rear bolt fully exposed.
This CLEARLY shows where the Nyloc nut was mounted on it.
picture.php



This is the Nyloc Nut that fell off.
I just found it in the upper pocket of my KLIM Jacket!
Notice that the Nylon Ring is UN CUT.
It has never had any bolt threads go through it.
picture.php



This is the tensioner bar showing the cut grove in the back to secure the nyloc nut from rotating.
picture.php
 
When the bolt is passed through the mounting plate you see this.
picture.php


NOTICE THE RELATIVE HEIGHT OF THE BOLT TO THE NUT!!
picture.php






This photo shows it is MECHANICALLY IMPOSSIBLE for the Nyloc to have ever gotten a bite on the bolt!

picture.php


The M12 Bolt supplied in the kit and pre-assembled from MPI is TOO SHORT!I stand by my opening statement.
This is 100% MPI's fault.

There is nothing I could have done to prevent this failure other than to have NOT used the MPI supplied bolt.
 
Last edited:
irondave86 said:
I have to agree with ZeeRTee, threads like this just add to MPI's already notoriously bad rep, and its not warranted. At least not in this case. :face-icon-small-con I'm not trying to bash you Christopher, but to those who understand how these pulleys work its obvious that this is NOT MPI's fault. Its 100% installer error. I have over 2000 very hard miles on my s/c with few issues. And I never check my pulleys anymore. I feel that when installed correctly there's no need too.

Many on here have said this before but ill say it again. Who does the install is just as important as who's kit you buy.
Click to expand...


Given the evidence I strongly disagree with you.
The installer followed the instructions TO THE VERY LETTER and did exactly as he was told. AND I called and spoke to MPI many times during the installation to point out discrepancies in their manual and suggest changes and upgrades to it.
 
Im no rocket scientist, BUT it seems a bit over kill to ave 100 posts about a rather mild problem that could have been easily fixed in the trailer with a few tools, and a trip to the hardware store. Nobody likes break downs, but in a time where we are making nearly double the HP that the sleds came with from the factory with and going places that by rights we probably shouldnt be going chit is gonna happen. Fix it and move on. Biggest problem I see here is how damn bad you are over analyzing this.
 
n2otoofast4u said:
Im no rocket scientist, BUT it seems a bit over kill to ave 100 posts about a rather mild problem that could have been easily fixed in the trailer with a few tools, and a trip to the hardware store. Nobody likes break downs, but in a time where we are making nearly double the HP that the sleds came with from the factory with and going places that by rights we probably shouldnt be going chit is gonna happen. Fix it and move on. Biggest problem I see here is how damn bad you are over analyzing this.
Click to expand...

I disagree on this. That pulley is essential for it to run. You pay over $4000 for that kit and MPI should be checking to make sure their kits ship out pre assembled correctly. I mean someone at MPI actually wrenched on the pulley to tighten up that bolt and didn't even look to see that it grabbed the threads. It's one thing if they accidentally grabbed a bolt from the wrong bin to throw in a bag, but this was assembled by MPI prior to shipment.

I think it is good for others so they can make sure they didn't get a short bolt as well.
 
field repir NOT

n2otoofast4u said:
Im no rocket scientist, BUT it seems a bit over kill to ave 100 posts about a rather mild problem that could have been easily fixed in the trailer with a few tools, and a trip to the hardware store. Nobody likes break downs, but in a time where we are making nearly double the HP that the sleds came with from the factory with and going places that by rights we probably shouldnt be going chit is gonna happen. Fix it and move on. Biggest problem I see here is how damn bad you are over analyzing this.
Click to expand...
If a bolt could have been located and a bearing found , knowing what to look for and making a repair takes some knowledge you have to remember that Christopher is a minor beginner at best with directions to follow a repair could have been made assuming all parts could have been found.
 
i would have seen that the bolt was too short taking the shipping plastic off the tensioner unit....do ya put on an oil filter and not check that it has rubber ring..???...willikers..this thread should have been a reality tv show...so what next..is
MPI going to jail....???...just joking...
 
The more appropriate question would be...

Do you buy a new car and REMOVE the factory installed oil filter to see if it has a rubber ring.??
 
Installer Error

The bolt through the idler pulley never was tightened properly.:face-icon-small-con

I really dislike how so many people will not take personal responsibility.

That polylock won't hold jack, it's the yield (stretch) of the bolt when tightened that keeps things in place. Do you think every bolt and nut on your sled is a lock fastener?, nope, do they all come loose if tightened properly?, nope. Is there a polylock on your con rod fasteners?, nope, do they come loose?, nope, do you think the con rods have less stress than a simple idler bolt?, nope. is there a lock on the crank bolt for the blower PTO drive bolt?, nope, do you think that bolt has less stress than the idler bolt?, nope, does it come loose?, nope.

Move on and quit blaming the mfg. :deadhorse:
 
christopher said:
When the bolt is passed through the mounting plate you see this.
picture.php


NOTICE THE RELATIVE HEIGHT OF THE BOLT TO THE NUT!!
picture.php






This photo shows it is MECHANICALLY IMPOSSIBLE for the Nyloc to have ever gotten a bite on the bolt!

picture.php


The M12 Bolt supplied in the kit and pre-assembled from MPI is TOO SHORT!I stand by my opening statement.
This is 100% MPI's fault.

There is nothing I could have done to prevent this failure other than to have NOT used the MPI supplied bolt.
Click to expand...

flip the nut over...roflmao
 
i still don;t like how the tension adjuster just pushes on the threads of the bolt on the pulley..its lame..some sort of push block would be more like the 21st century
 
Last edited:
ZeeRTee said:
The bolt through the idler pulley never was tightened properly.:face-icon-small-con

I really dislike how so many people will not take personal responsibility.

That polylock won't hold jack, it's the yield (stretch) of the bolt when tightened that keeps things in place. Do you think every bolt and nut on your sled is a lock fastener?, nope, do they all come loose if tightened properly?, nope. Is there a polylock on your con rod fasteners?, nope, do they come loose?, nope, do you think the con rods have less stress than a simple idler bolt?, nope. is there a lock on the crank bolt for the blower PTO drive bolt?, nope, do you think that bolt has less stress than the idler bolt?, nope, does it come loose?, nope.

Move on and quit blaming the mfg. :deadhorse:
Click to expand...

The whole point trying to be made was that pulley bolt came pre torqued and assembled from MPI. It was torqued before going to Canada. It's the fact that MPI supplied and installed a bolt too short.

And yes the nyloc helps hold tension from backing out. I NEVER see a bolt with a standard nut and no lock washer, or star washer or nyloc, or clip to keep it from backing out. The only time I see nothing is stuff that bolts in with no nut.

This thread is not about putting down MPI but showing people that even if you torque something designed to run a nyloc will back out since it isn't touching the nyloc portion.

Just wondering why you don't think some blame goes to MPI?? The part came PRE assembled, and no where in the instructions does it say to torque that bolt or even check it after a ride. So when a mfg puts something out are we all supposed to dissassemble and reassembled with what we think is the right torque? There were no torque numbers for that bolt so how do you know if it was or wasn't torqued correctly?

It's pretty much like saying well I bought a new car, so let me go buy a service manual and check torque specs for each bolt or its my fault something wasn't torqued right.
 
still trying to figure out why MOTO wouldnt want to drive a NHRA dragster to the grocery store. The beer would definitely stay cold for the trip home :face-icon-small-coo
 
to jsandgren10

No it's more like saying I bought a new car so let me take it home and put my monkey paws all over it and when it falls apart it's someone else's fault.
 
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