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Compression Help...please

Discussion in 'The Garage' started by noahrob, Nov 12, 2006.

  1. noahrob

    noahrob 1/2 ton status Author

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    Ok, Here is the deal, I am eating a lot of oil and don't have any drips. I also posted yesterday about backfires and what not here http://coloradok5.com/forums/showthread.php?t=189781
    but feel these issues are unrelated...maybe?

    I admit that I am a tool, so any and all help would be greatly appreciated.:bow:

    OK, here is the truck...1973 Blazer with a 383, Stage II Quadrajet, mild cam and a 4 speed, mechanical fuel pump and HEI. Here are the compression test results...Does this mean the driver side head is screwy and that the oil ring on #8 is shot?

    1) 130
    2) 130
    3) 95 and then 95 with oil
    4) 120
    5) 110 and then 110 with oil
    6) 130
    7) 120
    8) 105 and then 130 with oil

    Final question, any suggestions besides yanking it?

     
  2. 71 Blazer

    71 Blazer 1/2 ton status

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    I would be more worried about #3, looks like your valve is not seating right. You are allowed so much variation between all the cylinders. I can't remember how much, I think it is like 10%.
     
  3. ryoken

    ryoken Puppy Fabricator Premium Member GMOTM Winner

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    Yeah, some not great numbers there.... Definitely a valve prob on #3, it looks like #5 got a valve issue too, thats more than 10%...and #8 could be rings or a cylinder wall issue...
     
  4. noahrob

    noahrob 1/2 ton status Author

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    Thankis for the feedback...any other thoughts, anybody?
     
  5. ARAMP1

    ARAMP1 Aviator Extraordinaire

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    What does the coolant look like? Any coolant loss?
     
  6. noahrob

    noahrob 1/2 ton status Author

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    Nope, coolant is good. I started becasue of lose of oil, but am fairly confident the head gasket is good.
     
  7. roadnotca

    roadnotca 3/4 ton status

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    X2, valve seats on 3-5. Reads like an EGR head. X2 on #8, rings or sealing, but you'd think that would be OK when running.
     
  8. noahrob

    noahrob 1/2 ton status Author

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    Hmmm...Now I need to decide what to do? The Ramjet is still a year away, so I'll probably just keep dumping oil in it...
     
  9. noahrob

    noahrob 1/2 ton status Author

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    Decided to do another check since I was changing plugs...

    1) 90
    2) 90
    3) 90
    4) 110
    5) 90
    6) 130
    7) 100
    8) 100


    So, at least for the most part there is more consistency...really all I can conclude is my compression gauge needle is stuck, even though it is brand new...:doah:
     
  10. roadnotca

    roadnotca 3/4 ton status

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    R U giving it a "snug" fit with the fitting at the spark plug hole?
     

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