Crank concentricity

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01-03-2019 | 07:31 AM
  #1  
Just going through a dry fit and measuring clearances and have a quick question. Main journals 2&4 measure .002 and if rotated 180* measure .003 plus, the crank measures with in spec so I have two journals running out a little.

Anythings to worry about? was thinking of getting a set of X bearing to level it out!!
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01-03-2019 | 07:34 AM
  #2  
Put the crank in some V blocks and Check the run out. I would get the crank fixed if it has an issue
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01-03-2019 | 08:07 AM
  #3  
I left the crank in the block and put a DTI on 2&4 and get .01mm/0004 inch not much of an error?
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01-03-2019 | 10:04 AM
  #4  
If you're in Florida bring it and I'll straighten it no charge if not you're welcome to send it UPS and I'll take care of it for you. Sincerely Laz
P.S. stop down and see us at the Miami Boat Show booth F419 same as last year
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01-03-2019 | 11:41 AM
  #5  
Quote: If you're in Florida bring it and I'll straighten it no charge if not you're welcome to send it UPS and I'll take care of it for you. Sincerely Laz
P.S. stop down and see us at the Miami Boat Show booth F419 same as last year
WOW what a super cool and generous offer , being in Canada the shipping would be more than the crank is worth, lol. Wish I was in Florida right now it's freaking cold up here right now hahaha.
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01-03-2019 | 12:11 PM
  #6  
If it turns free send it. They straighten new cranks with a Hammer and round chisel same as billet camshafts. Are you having a problem with run out or out of round journals?
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01-03-2019 | 12:26 PM
  #7  
Quote: If it turns free send it. They straighten new cranks with a Hammer and round chisel same as billet camshafts. Are you having a problem with run out or out of round journals?
It turns free I was just checking the clearances before I assemble it and noticed 2 & 4 where on the smaller side of what I like. Just not sure if 1/2 thou is anything to worry about. 100% run out it's not out of round!
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01-03-2019 | 12:47 PM
  #8  
.002 is a little snug are you using a good bore gage? You can try shuffling some bearings around and check again.
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01-03-2019 | 12:57 PM
  #9  
Quote: .002 is a little snug are you using a good bore gage? You can try shuffling some bearings around and check again.
The way I checked it was to do a dry assembly with the new bearing, disassemble and use Clevite plastigage to measure the clearances, on 2&4 I rotated the crank 180* and rechecked. I then removed all the caps and using a DTI checked all the bearings 1,3&5 run true and 2&4 have .0004 run out.
I like your idea of swapping some bearing around but I still have .0004 runout and not sure if that's a problem or not.
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01-03-2019 | 03:02 PM
  #10  
.0004 is nothing to worry about. Actually it is pretty good Do you have oil on the bearings when you are checking the clearance ? That will make them a little tighter.
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