Post engine assembly free rotation verification

Small Block Mopar Engine

  1. 65TRAD270

    65TRAD270 New Member

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    I am at a point of a rebuild of a 273 ci engine and was wondering if there is some verification process for free rotation of engine components. After installing crank with new main bearings the crank turned freely by hand. Progressing with installation of connecting rods and pistons with new bearings and rings, components have tightened up considerably. Is there a torque test that can be performed to verify if too much drag has been induced through improper assembly? Using a torque wrench on the crank shaft I am exerting approx. 20/30 ft pounds of torque to initiate rotation.

    Any feedback would be appreciated.

    65TRAD270
     
  2. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    It will depend a lot on the drag on the rings. I would not consider 30 ft-lb to be at all excessive
     
  3. DartVadar

    DartVadar Well-Known Member

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    It funny because I asked the exact same thing when I put mine together. Sounds like everything is fine, mine was around 27 foot pounds. Its been running happily for 2k miles now so it must be fine.

    Here is the thread I started in this. http://www.forabodiesonly.com/mopar/showthread.php?t=269590
     
  4. nothingbutdarts

    nothingbutdarts Well-Known Member

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    Did you check crank end play and rod side clearances?
     
  5. Rapid Robert

    Rapid Robert Well-Known Member

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    You are fine. You do wanna "shake your rods" as in move the 2 big ends on each journal to see if they are free but with 20-30 lbs you are fine
     
  6. autoxcuda

    autoxcuda Well-Known Member

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    That's a very good checking method.

    What I learned was to check the torque after each piston is installed in the short block. And write that number down.

    You'll see a pattern of the torque increases. If the torque shoots way up after one piston install or too low, you need to investigate. Maybe you forgot to torque something down or torqued too much, or... That way you can pinpoint it down immediately to the piston assy or journal you just messed with.

    certain torque resistance
     
  7. Denvermike

    Denvermike Well-Known Member

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    When I checked the 360 I'm putting together , it took right at 30 Ft. lb. to turn it.
    Mike
     
  8. perfacar

    perfacar Well-Known Member

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    hi, what kind of torque wrench did you use? a click or a beam style?? beam style will show more accurate results. was this break away torque or what it took to rotate it?
     
  9. autoxcuda

    autoxcuda Well-Known Member

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    Beam type.

    We recorded both breakaway and rotational.
     
  10. dustoff440

    dustoff440 Well-Known Member

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    my stock short block 360 magnum dialed in at 27 lbs
     
  11. pishta

    pishta I know I'm right....

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    if its locked up, you got a rod cap backwards. Not that hard to do especially if your new to this. Also make sure your 3 and 8 caps are not swapped. I did this once and even the machine shop had given the rods to me cap-swapped. Looked the same, took a zoomed cell phone photo (love those) to positiveley ID them (plus they fit better correct, but barely!) I got a 273 on the stand that I can spin by hand, and its got pistons in it! Of course it has over 100K on them....
     
  12. Rob R

    Rob R Well-Known Member

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    5/64 rings really drag...
    IMHO 30 lbs with no valve train is excessive..Poink the crank a couple of times to set the center main and see if it improves..
    When I did Ifitsgotwheels 273, it turned with the valve train adj less than 30 lbs.It did have almost an extra 2 tenths piston to wall..
    So much can cause drag...rear seal type..crank run out..main alignment ..cyl wall finish..oil ring type..compression rings..brg clearance..it goes on and on.
     
  13. madscientist

    madscientist Banned

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    Define "poink".

    Is that REALLY a word?
     
  14. Rob R

    Rob R Well-Known Member

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    Poink...when you take a dead blow hammer and strike the snout of the crank,you do this sometimes to try and gain end play by seating the thrusts on a main brg..
    When you strike the snout of the crank it makes a Poink sound...:wink:
     
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    • Cudafever

      Cudafever Well-Known Member

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      My first eng had 100 psi torque to turn the crank!(just the crank) call my machines and he had me bring it back.

      one "line bore" latter and it turn vary free.

      30 don't sound like to much to me, but i would verify, as others have said, make sure you can slide the two rods on each throw easily and that the rod/wrist pin moves back and forth as well.
       
    • perfacar

      perfacar Well-Known Member

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      hi, anything under 20 is wonderful. race engine , 5 # rollover
       
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