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How easily should you be able to turn over SBC with plugs in

Discussion in 'Garage' started by AuroraGirl, Oct 12, 2020.

  1. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

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    1 foot breaker bar on a appropiate socket just past the pulley. not in a very leveraged position. In taking pulley off before, I turned it over about 1/4 turn before i could get the bolt off, and it bled off to get there. like a gas strut compress

    I havent cranked anything except a 20hp kohler and a 1940s tractor by "hand" so im not sure if that means i should find the compression tester or not worry about it
     
  2. OldBlueDually

    OldBlueDually Full Access Member

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    What is it you are trying to do? You mention removing a pulley in the past, and also finding a compression tester? You trying to do a compression test on a cylinder?

    If you are just trying to turn it over by hand, it should go fine. I have done it before. On my 5.7 Vortec I was able to use a 3/4 ratchet on the alternator pulley nut and turn the engine over using that.
     
  3. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

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    im asking if turning by hand with what i said sounded too easy, so low compression. but it sounds like if you are able to use the alternator.. which might give you a gear advantage? idfk, either way if what I said doesnt sound like its "too easy" it probably isnt.
     
  4. OldBlueDually

    OldBlueDually Full Access Member

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    Ok I get it now :D

    Any engine with a breaker bar or a large ratchet I have turned over has been fairly easy to do. With my flathead V8 I just grab the fan and it turns with little effort. On my Vortec depending on which direction I went I may have to push on the belt a little to keep the alternator from slipping.

    I recently spun over my 455 Olds, and that took a little more force to do, but I was still able to. My 5.7 turned easier however.

    Not sure if the above is of any help, but that is my experience.
     
  5. Swearbody

    Swearbody Supporting Member Supporting Member

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    No it seems fine to me. I am able to rotate a sbc with the plugs in fairly easily. It will give not give even resistance like when the plugs are removed( it will compress and release pressure) making it harder to control the stopping point( it will be easy, then it wont, then it will again) but turns none the less.
    It will "bleed off" through the valves unless it on a tdc on a particular cylinder that you are testing...meaning all the cylinders that arent on tdc will pass air through them.
     
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  6. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

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    okay i didnt think about it like that, 8 cylinders compared to 3 and 4 means a lot of them are opening and closing at "barely" amounts while the ones i have turned over have a lot less seamless transition
     

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