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engine rebuilding trouble

Discussion in 'The Garage' started by 1979jimmy350, Aug 1, 2006.

  1. 1979jimmy350

    1979jimmy350 1/2 ton status

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    Im working on rebuilding a small block and am running in to some trouble. I installed the crank and checked all the clearences and every thing was fine. I started to install the pistions and began to run into trouble. The engine is very hard to turn over, i can't even turn it by hand. I have standard pistions, and rings. I checked all the ring gaps and they were fine. I am getting very confused at this. I have no idea what could be causing the engine not to turn over
     
  2. Cornfield creations

    Cornfield creations 1/2 ton status

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    did it turn over with just the crank in there? Or did it get tight after the pistons were put in?

    #1 check, make sure you have every main cap in it's own correct spot and turned correctly. They can be mixed up and it can cause the crank to seize. Wasn't paying attention on my own and did that.

    If the main caps check out all right, make sure you have the right bearings with enough gap, check with plasti-gauge.
     
  3. xpndbl3

    xpndbl3 1/2 ton status

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    i've never been able to turn a fresh motor over by hand just off the crank balancer. i can however turn them over by a breaker bar off the snout and a crank adapter, or by using the flexplate off the back sometimes.
     
  4. neverendingproject

    neverendingproject 1/2 ton status

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    When I rebuilt mine, it was pretty tough. It took some effort, but I could turn it by hand off the flexpalte.
     
  5. chevyryan

    chevyryan Registered Member

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    just like the first person said, you definately need to check all your main caps and bearings, they are easy to mix up and wont work propperly if not in the correct place. but yea, it probably will be a little harder after being rebuilt
     
  6. 1979jimmy350

    1979jimmy350 1/2 ton status

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    the crank spun with no problem before the pistions were installed. I even installed the flexplat and can not turn it over by hand, but i can with a prybar
     
  7. K5er4Life

    K5er4Life 1/2 ton status

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    you wont be able to turn the crank by hand with the pistons installed. Theres only two people I can think of that can do that, probably Mr. T and Chuck Norris. :D I dont remember exactly but if you look it up theres a specification that indicates the maximum allowed rotating torque of the crank, without pistons installed. If that checks out, and you have the proper piston to wall clearance, and rings are gapped properly then you are good to go. Like mentioned though, dont forget to check bearing cap posistion and orientation, and there clearance as well. I once got a set of bearings that were .010" undersized for my stock sized crank journals.
     
  8. 1979jimmy350

    1979jimmy350 1/2 ton status

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    yea im thinkig it might be rob bearings, i installed a starter on the engine and it won't even turn it over at all
     
  9. K5er4Life

    K5er4Life 1/2 ton status

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    wow, if a starter (assuming its good and getting enough power) wont turn it over then you definitely need to go back and recheck everything.
     
  10. bigbadchev84

    bigbadchev84 1/2 ton status

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    i had the same problem on my ford, turns out i had the rods installed wrong, where the crank is turned down for the rods to connect there is a slight bevel, in the rods one side has that bevel also, i had the flat edge against the bevel...no good. i switched them around and everything was fine, ever since then i # them to the holes so i dont get them confused. might be worth a try
     
  11. 1979jimmy350

    1979jimmy350 1/2 ton status

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    well after a visit to the parts store to compare the bearing they had and another call to federal mogual i found out that they were the wrong bearings in the wrong box, so summit is shippng me new ones
     
  12. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Wrong bearings in the box isn't good, but you should have caught that when assembling the engine. That is if you either mic'ed the crank or used plasti-gage.
     
  13. 1979jimmy350

    1979jimmy350 1/2 ton status

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    i had not gotten to the point of platic gague yet, so there is no way i could have caught it earlier.
     
  14. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    If you already put the pistons into the block then you would already have plasti-gaged it. :confused:
     
  15. 1979jimmy350

    1979jimmy350 1/2 ton status

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    im talking about the rod bearings, you platicgague them after the pistions are in
     
  16. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Yes, the rod bearings are plasti-gaged after the piston has been installed, unless of course you checked your clearances on the crank with plasti-gage before you even installed the pistons into the bores by torquing the rods to the crank before even the crank was installed. If you did the latter and your clearances were good then you have a bent or twisted rod.
     

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