1. Registration trouble? Please use the "Contact Us" link at the bottom right corner of the page and your issue will be resolved.
    Dismiss Notice

Interpretation please

Discussion in 'Early CJ5 and CJ6 Tech' started by johnsotd, Sep 14, 2007.

  1. Sep 14, 2007
    johnsotd

    johnsotd Member

    Senatobia, MS
    Joined:
    Apr 23, 2006
    Messages:
    454
    I received a new-to-me dauntless 225 ('65, milage unknown) to go in my 2A today and ran a compression check on a cold engine. The numbers were
    120, 130, 110, 120, 130, and 120.
    I know these cylinders are not within 10% of each other but I would really appreciate anyone with experience giving me their thoughts.
    Tommy
     
  2. Sep 14, 2007
    jpflat2a

    jpflat2a what's that noise?

    Riverside CA
    Joined:
    Jul 30, 2003
    Messages:
    7,889
    carboned valves ?
    burnt valve ?
    rings on the one cylinder ?
    who knows, a leakage test would be helpful by introducing compressed air into the cylinder, then listening thru the exhaust or the crankcase.
    personally, I wouldn't worry about it and go ahead and run it
     
  3. Sep 15, 2007
    MOP

    MOP Active Member

    Manhattan, KS
    Joined:
    Sep 25, 2003
    Messages:
    1,133
    I've put ~10K miles on mine in the past 4 years with compression ratings of something like 125, 75, 125, 130, 120, 125. R)

    I think you'll be fine :v6:
     
  4. Sep 15, 2007
    packrat2A

    packrat2A Member

    McAlester, OK
    Joined:
    Oct 23, 2004
    Messages:
    212
    The lowest reading is the cylinder that had a valve open to the air while it sat. Nothing to worry about, and the general specs are 10-15%. Those #'s look good to me!
     
  5. Sep 15, 2007
    JeepTherapy

    JeepTherapy Sponsor

    Negaunee, Michigan
    Joined:
    Jun 29, 2006
    Messages:
    699
    I would certainly run it.
     
  6. Sep 15, 2007
    kaiser_willys

    kaiser_willys Well-Known Member

    Joined:
    Jan 7, 2007
    Messages:
    1,524
    #'s look real good to me,squirt a little wd40 or something simular in the low cylinder and i would bet that the compression reading will come up to the rest or maybe higher,got any way to test fire it on a engine stand for about 30 seconds? hook up a oil psi gauge,and you will have a good idea about the bottom end before you install it into the jeep,careful running it very long will heat it up quick without coolant
     
    Last edited: Sep 15, 2007
  7. Sep 15, 2007
    Patrick

    Patrick Super Moderator Staff Member

    Los Alamos, NM
    Joined:
    Sep 22, 2002
    Messages:
    8,371
    Run it....
     
  8. Sep 15, 2007
    OzFin

    OzFin Vintage Jeep Guy

    Michigan
    Joined:
    Jul 16, 2007
    Messages:
    547
    I would do a wet compression check , check the oil pressure and if all seems good(compression not bad as it is now) install and run it. For whats its worth I would run some Marvel Myst. oil in the gas and crankcase for the first couple hundred miles or 5 hours operating time.By the way look over the water jacket soft plugs real close ....it's a lot easyer to change them now (if needed) than after the installation into the Jeep. Look over the front and rear mian seals too.
     
  9. Sep 15, 2007
    johnsotd

    johnsotd Member

    Senatobia, MS
    Joined:
    Apr 23, 2006
    Messages:
    454
    Folks,
    Thanks a lot for your input. I feel much better now. Sounds like I can avoid an expensive teardown.
    I think I'll clean it up and install it.
    Tommy
     
  10. Sep 15, 2007
    crazy4ink

    crazy4ink New Member

    Millmont, PA
    Joined:
    Sep 4, 2007
    Messages:
    28
    If I was in your position, I would just clean the exterior of the engine and run it. For being given and engine, those are good compression numbers! Be glad it didn't have a gaping hole in the side!
     
  11. Sep 15, 2007
    66cj5

    66cj5 Jeep with no name

    NorthWest Indiana
    Joined:
    Sep 10, 2003
    Messages:
    2,069
    I'd pull the valve covers off to check for sludge, depending on the results the oil pan as well. easy to check since it's not installed.
     
  12. Sep 15, 2007
    Hansh

    Hansh Going Mobile

    SE Wisconsin
    Joined:
    Dec 7, 2004
    Messages:
    425
    It's an odd fire, you'll never notice.:rofl:
     
  13. Sep 15, 2007
    timgr

    timgr Jeepin' Nerd 2020 Sponsor 2019 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    20,431
    Depends on your definitions. If it's plus or minus 10%, then they are in spec. The mean is 121.8, and the range then is 109.5 to 133.8. Even if 10% means a total of 10%, or +/- 5%, they are still pretty close to in spec (115.6 to 127.8). I'd say drive it.
     
  14. Sep 17, 2007
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
    Joined:
    Sep 23, 2002
    Messages:
    11,523
    I also say put it in and run it. The readings aren't all that accurate on a cold motor that hasn't been run for who knows how long anyway. At least you know there's nothing major wrong. Nickmil
     

Share This Page

New Posts