Triton 5.4 Rebuild - Bearing Slap or Crankshaft R&R?

Discussion in 'General Chit Chat' started by shoon, Feb 12, 2018.

  1. shoon

    shoon cliTaurus

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    Rebuilding another Triton 5.4 2v out of a F150 7700. Stock rebuild. Not looking to add horsepower or modify.
    Tried asking on the F150 forums but they aren't overly active, figured I'd get a couple more opinions and check in again with the SHO community!

    I'm heavily debating throwing new main and rod bearings in ($70) VS replacing with a machined crank that includes oversized bearings ($350).
    The third option to polish and recondition the existing crank and buy new bearings is the most expensive option. A job like this it's easy to throw money and buy everything new, but I want to justify the expense is totally worth it before pulling the pin.

    If the crankshaft journals are completely clean / clear of defect and measure well within spec, is there any harm throwing in a new set of main, thrust, and rod bearings and calling it good? I intend to torque and plastigauge everything of course. I suspect given that the bearings are the softest material there should be minimal wear/erosion to the journals.

    As pictures, there's not a huge amount of wear on the bearings. tiny bit of scoring on the one main bearing (shown) where it looks like a bit of oil contamination. The crank appears clean and unscathed despite the one main bearing picture.

    [​IMG]
    [​IMG]

    Thoughts?
     
  2. luigisho

    luigisho SHO Member

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    Are those supposed to show copper with excessive wear?
     
  3. shoon

    shoon cliTaurus

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    I think these stock bearings do not have a copper layer to them. I took a knife and tried to scrape down a ways into the bearing but there was no copper.
     
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  4. zak

    zak SHO Member

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    Can you put a pair of new main bearings in, with some Plastigauge, torque down that journal around the crank, and determine how much clearance it has?

    Your approach of replacing main and rod bearing only is likely valid, but that is one way to find out - to be meticulous you would check all rod and main bearings.. Using a micrometer and checking each rod or main bearing diameter on the crank, in two directions, would also be worthwhile.
     
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  5. OG-SHOguy

    OG-SHOguy Old member SHOwht90

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    Agreed 100%, This is the only way to do it right...good luck with your build!
     
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  6. rubydist

    rubydist Moderator Staff Member

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    I see nothing from those photos that would deter me from just putting in new bearings and moving on. The mod motors are fairly sensitive to bearing clearance, and I would very carefully measure the rod journals to make sure if you need standard or .001" under bearings. I would expect the mains to be fine with standard bearings, as they do not wear as quickly as the rod journals. As zak indicates above, measure w/ a mike in at least 2 directions to be sure of the actual journal size.
     
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  7. shoon

    shoon cliTaurus

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    Thanks for the advice!
    I went out and measured all of the journals. Here is the spec I found and measurements below. My mic only goes to 3 decimal places, so wondering if I should order a better micrometer.

    They appear to all be on the lower end of spec and not finding any out of round. There was one main journal closest to he flexplate / Torque converter that measured lower than the others and appears to be under spec by around ~0.001" + .. I'll take another stab at measuring these again when I get a better micrometer.

    My measurements:
    Mains: 2.654 - 2.656"
    Rods: 2.085" - 2.086"
    Specifications:
    [​IMG]

    I'm still leaning towards the new bearings and plastigauge method. Any tips for cleaning the journals of oil deposits without damaging them?
     
  8. pjtoledo

    pjtoledo 'ol man in the SHO

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    try Ford truck enthusiast forum: ford-trucks.com
     
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  9. rubydist

    rubydist Moderator Staff Member

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    If your mic is correct, I would order .001 undersize for both mains and rods. If you plastigage them, you will know if they end up too tight, in which case you would need some standard size. You may end up mixing both sizes to get them in spec.

    I would not worry much about the little discoloration from the oil on the ends of the journals - hit it with a rag with some acetone on it, and take off what you can and ignore the rest.
     
  10. OG-SHOguy

    OG-SHOguy Old member SHOwht90

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    Looks to me that your main journals are undersized according to the table, i would mic the crank journals and the crank itself to check for roundness... usually when you get wear like what the bearings show you will be out of round....the old bearings show excessive wear in two spots on bearing indicating that there may be a roundness issue. Better to be safe.
     
    Last edited: Feb 14, 2018
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  11. luigisho

    luigisho SHO Member

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    Just curious, how many miles on the Triton?
     
  12. OG-SHOguy

    OG-SHOguy Old member SHOwht90

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    see if you can borrow or buy a Mitutoyo, Brown and Sharpe, or Starrett set of mics, they will be the most accurate and go down to the 4th decimal. local machine shop would have no problem getting you precise measurements or possibly have someone that would let you borrow mics.
     
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  13. SoonerLS

    SoonerLS Heed.Obey.Serve

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    FWIW, F150Forum is very active in the 12th Gen ('09-'14) section, but you only have two years of Mod Motors/Tritons in that gen. FTE ( https://www.ford-trucks.com/forums/index.php ) isn't particularly active in the 12th Gen section, but it's very active in others, so you might have better luck there.
     
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