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Thread: compression ratio

  1. #1
    Member CRAFTSMAN
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    compression ratio

    can anyone tell how to figure compression ratio without taking the heads off?
    I have a sbford 302,stock pistons w/.030 overbore, `78 351W heads w/ 202 intake valves, milled(don't know how much). :?

  2. #2
    Senior Member MASTER BUILDER
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    CR

    You would have to know what piston and what chamber CC you have to figure this. Later J.Smith 4621 racing

  3. #3
    Member JUNIOR BUILDER
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    the only way I'd imagine that this could be done would be to fill the cylinder @ tdc & bdc with fluid & calc from that,though sealing may present a problem

  4. #4
    You can buy a compression gauge from an auto parts store that you put in place of the spark plug and bump the engine over. It has a reset on it that locks it in place while you are bumping the engine from the driver seat, or you could have a buddy do it while you watch it. Put it in every cylinder and write it down on paper, then add them all together. Take that number and divide it by the number of cylinders, and you will get a round about compression ratio.

  5. #5
    Senior Member RACING JUNKIE
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    ??? :shock: :shock:

  6. #6
    Senior Member RACING JUNKIE
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    Quote Originally Posted by MEMRACING62
    ??? :shock: :shock:
    Confused? me too :shock: :?
    No matter where you go, there you are.
    **IN GOD WE TRUST**

  7. #7
    Senior Member RACING JUNKIE
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    must some kinda new math!! :lol: :lol:

  8. #8
    Senior Member SENIOR BUILDER
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    Quote Originally Posted by Jordan1984
    You can buy a compression gauge from an auto parts store that you put in place of the spark plug and bump the engine over. It has a reset on it that locks it in place while you are bumping the engine from the driver seat, or you could have a buddy do it while you watch it. Put it in every cylinder and write it down on paper, then add them all together. Take that number and divide it by the number of cylinders, and you will get a round about compression ratio.

    :shock: All that will get you is an average cranking psi :roll:

  9. #9
    Senior Member RACING JUNKIE
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    Holy Cow My compression ratio is 245 to 1!!!!

  10. #10
    Senior Member RACING JUNKIE BEAST477's Avatar
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    Quote Originally Posted by Tod74
    Holy Cow My compression ratio is 245 to 1!!!!
    WOW Tod, where do you get fuel for that? :shock:
    BEAST477






    Only a rich man can afford to use cheap parts.

    http://www.racingjunk.com/profile/177549


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