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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  14. shoon

    shoon cliTaurus

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    Approximately 240,000 Miles

    Funny you mention that, I've been looking at getting a set of Mitutoyos- specifically 500-196-30.


    I can only seem to find .25 mm .50mm and .75mm undersized bearings- which 0.25mm = 0.01" correct? I think that might be a bit too tight. Still waiting on a mic, but will figure it out soon.
     
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  15. OG-SHOguy

    OG-SHOguy Old member SHOwht90

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    0.25mm = 0.0098425197" , The .25mm bearings will mean you have to under grind your crank. Your measurements say that you are looking for a +.001" bearing.. if you cannot find a +.001" bearing then you are looking at having the crank ground....I think I would try the local salvage yard if you cant find any and source a crank to avoid the grinding....just my $0.02

    Calculations fixed! thanks again rudydist!
     
    Last edited: Feb 26, 2018
  16. rubydist

    rubydist Moderator Staff Member

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    .25mm = 0.0098" not 0.00098" as posted above. What the op needs is a .001" undersized bearing, not a .010" bearing - to use a .010" bearing the crank must be ground.

    If there are no .025mm bearings available, then the choices are as follows: 1. buy reground crank w/ proper bearings, 2. have current crank reground for .25mm bearings, 3. put it together with standard bearings and use 5W30 or 0W40 oil rather than 5W20. I am not a fan of choice #3 on the mod motors as the whole thing is clearanced for 5W20 oil.
     
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  17. OG-SHOguy

    OG-SHOguy Old member SHOwht90

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    you are correct....i accidentally put an extra zero in there, thank you for correcting that rudydist...i will fix it so there is no confusion...sorry guys.
     
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  18. shoon

    shoon cliTaurus

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    I just read a really good article by Mahle pertaining to bearing wear / identification and it included some information on grinding and polishing. I posted a link to the article below if anyone is interested.

    "...Not only is it important that the surface finish
    meet recommended average Ra or better, but it is also important to always
    grind opposite to rotation and polish in the direction of rotation. Otherwise it
    is possible for these microscopic burrs to disrupt the oil film and abrade away
    the bearing surface."


    https://www.mahle-aftermarket.com/m...b-2-1114-engine-bearing-failures-brochure.pdf
     
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  19. luigisho

    luigisho SHO Member

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    We have seen failures in machining cranks in the SHO. Is the crank in the 5.4 more amenable to machining without effecting hardness? Is there an off the shelf replacement that's not terribly expensive?
     
  20. shoon

    shoon cliTaurus

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    I suspect the rod journals are larger on the 5.4 crankshaft.
    The triton operates at a much lower RPM than the SHO. I'm running a machined crank in my daily driver now, and have not had issues.

    Rock auto sells a machined crank
     
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