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350 engine acting like mosquito fogger....

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by fjleiter, Jun 7, 2004.

  1. fjleiter

    fjleiter 1/2 ton status

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    Location:
    Palmyra, NY
    Trying to track down what the heck the problem is, have a new engine on the way but won't be ready till fall ($$$ issues). Here's the problem

    1) Typical puff of smoke on startup (valve seals...)

    2) Puffs smoke when decelerating and tranny shifts down

    3) If I sit in the truck while it's in park and pump the gas bringing it from idle to approx 2500 r.p.m then back to idle (repeating this over and over) I't will produce so much smoke that I can drop visibility low enough I can not see the house which is less than 20 feet away. Pumps out MASSIVE amounts of smoke. If I drive it, it does not do this, smoke a little but doesn't leave huge clouds behind me (except as noted in item #2)

    4) Did a compression test, all cylinders are running 150#, no appreciable change on wet test (squirting oil in cylinders)

    5) all spark plugs are nice and clean except for #1 which oil fouls and has to be cleaned or replaced every 250 miles or so.

    Figured maybe a ring problem on #1 but matches the others on compression test and no change on wet test. other idea would be valve guides or seals but its pumping out WAY to much oil smoke (see #3)

    Have the parts to do a top end right now (heads etc..) but don't want to tear it down to find it's the bottom end needing help and have it sit for a couple months waiting on a replacement engine.

    Don't drive it every day but do use it as a backup vehicle (drives, just runs kinda crappy) so I would prefer not to have it incapacitated for the next couple months if you know what I mean...

    Any ideas????
     
  2. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    Sheridan, Michigan
    a guy around the corner from me had the same problem, turns out it was a valve seal on the #3 exhaust, it was bad, very bad, almost not there. it had a thick coating of oil in the exahust. when you ran your finger in the pipe, it was almost dripping from oil. /forums/images/graemlins/yikes.gif /forums/images/graemlins/yikes.gif /forums/images/graemlins/yikes.gif
     
  3. Thunder

    Thunder 3/4 ton status

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    Just do the valve seals. Its a pretty easy job and doesn't cost much to do. The way you describe it. The #1 seal is gone. A bad seal will put a lot of oil down into the combustion chamber and out exhaust port where it will cause a lot of smoke.
    Smoking on De-accel is also a common sign of bad valve seals.
    The rings are prolly ok if there is no change between the dry and wet compression test.
     
  4. Thumper

    Thumper 1/2 ton status

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    Location:
    Alberta Canada
    Wow... that describes exactly what mine is doing now. Except mine smokes when I shift (std). I am going to town right now in fact to pick up a top end gasket set, so hopefully i can get it done and will let you know!
    Mike
     

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