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Oil coming from exhaust 350 Chevy

Discussion in 'The Hokey Ass Message Board' started by BlackCherryImpala, Sep 19, 2008.

  1. BlackCherryImpala
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    BlackCherryImpala Member

    I bought a 350 Chevy cheap from a 78 pickup that was rebuilt only 1600 miles ago. The problem is that is has some oil coming from the exhaust. I have built a number of small blocks but have never encountered this problem. What do you guys think? Is it possibly a valve guide or a bad valve seal or could it be something deeper like a broken ring or bad ring seating? The engine was built by a shop in the stock configuration and it was not making any abnormal noises when the oil began dripping from the exhaust. It did not smoke at all apparently.
    Thank You,
    BlackCherry
  2. Ebbsspeed
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    Ebbsspeed
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    It has oil dripping from the exhaust, but it doesn't smoke? Are you sure it's not just sooty condensation (ie, dirty water)?
  3. daddio211
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    daddio211
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    Yep, what Ebb said... but my first thought was a broken ring, or the gaps are all lined up in the rings. Have you checked compression?
  4. BlackCherryImpala
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    BlackCherryImpala Member

    I'm not for sure as I'm getting the information 3rd hand. You would think the heat from the exhaust would turn the oil into smoke. The retired gentleman that had it pulled it back out of his pickup stated that it was oil. I don't know how engine inclined he is, however, I know he owned a lumber company for 40 years. I looked at the exhaust ports and they did not have any unusual characteristics about them and the lifter valley appeared very clean.
    Thank You
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  5. Mudslinger
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    Mudslinger Member

    What about an exhaust valve oil seal leaking? Or missing?
  6. Bluto
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    Bluto Member

    I'd be hangin qt cans off the pipe an' selling it!! :)
  7. Searcher
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    Searcher Member

    What do the plugs look like ?
  8. BlackCherryImpala
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    BlackCherryImpala Member

    I haven't checked anything as it is sitting on a stand. I think I'll likely just take the heads off first and check them out and also inspect for a broken ring and if that doesn't work I'll start pulling pistons. I had not thought of someone being so careless as to lining up the rings, but a shop in a hurry very well could have done just that. The gentleman that owned the engine spent somewhere around $2000 on the rebuild, and when he discovered the problem spent another $2600 for a new engine. He must really love his 78 Cheyenne.
    Thanks for the replies.
    BlackCherry
  9. dirty old man
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    dirty old man
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    My thoghts also lean towards condensate water colored black with carbon.
    Before I pulled the heads I'd just pull the exhausr manifolds if you haven't already, and check the exhaust ports in the heads for signs of oil.
    It would take one helluva lot of oil to get enough to run out the erxhaust pipe and that Mutha would smoke like a coal powered train!
    If it were mine and there wasn't any appreciable amount of oil in the ports I'd install that Mutha.
    You just may have bought yourself a deal!
    Keep us informed!
    Dave
  10. skwurl
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    skwurl Member

    are you sure its oil and not waterand carbo dripping? I started my bike yesterday and got a facefull of wet carbon
  11. Mudslinger
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    Mudslinger Member

    What he said!
    Your mufflers should be loaded with oil if its leaking that much.
  12. skwurl
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    skwurl Member

    Lined up rings will cause a loss of compression not oil loss or consumption.
  13. BlackCherryImpala
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    BlackCherryImpala Member

    There was no oil in the exhaust ports, only the normal black carbon. I think I'll pull the valve covers and check the valve seals and if they are ok I'll plug it into my parts truck. Maybe the man had the carb running too rich or the timing was off producing the carbon mixed with the condensation making it appear as oil. I know the man is a perfectionist and his ways may have led me into a nearly new engine for next to nothing. That would be great. i deserve a break today and I'm really not into McDonald's.
    Thanks for all the replies. You are good men, and women.
    BlackCherry
  14. Engine Pro 5X
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    Engine Pro 5X Member

    Isn't that normal ??? LOL >>>>.
  15. Bluto
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    Bluto Member

    I got a couple race motors that 'make water' folks keep tellin me You blew a head gasket! It's like listening to my ex-wife ......... I just playing DEVO inside my head and keep nodding knowingly as if I was listening :)
  16. Engine Pro 5X
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    Engine Pro 5X Member

    Do you have one of those clay pots on your noggin while listening to DEVO???? >>>>.
  17. Bluto
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    Bluto Member

    PLASTIC!! Are we not men????

    But my yellow suit don't fit no more

    I do listen to Yellow
  18. Cal Cowboy
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    Cal Cowboy BANNED

    When my rod with the SB 350 or my Goat (389) sit for a couple of weeks, they both have black water comming out of the exhaust. It's thicker than tap water because it has carbon in it. When I get home and the spots are dry I sweep up the carbon.
  19. jonny o
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    jonny o Member

    Pcv sucking oil into the chamber? Plugs will obviously show that.
  20. THE CHIEF
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    THE CHIEF Member

    yea i got black water coming out of 1 exhaust pipe, still dont know where the hell it comes from? any ideas? it does it sometime not always
  21. Von Rigg Fink
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    Von Rigg Fink Member

    im thinking condensation..mixed with carbon too
  22. hustlinhillbilly
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    hustlinhillbilly Member

    It's gotta be condensation mixed with soot. Like the man said, for it to be oil, the mufflers would have to have an ungawdly amount of oil in them.
  23. THE CHIEF
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    THE CHIEF Member

    so then its not a blown head gasket? why would it be comming from only one side?
  24. d2_willys
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    d2_willys Member

    If you had smoke I would check the transmission vacuum modulator or power brake booster, but with no smoke, the only guess I have is that you have a cracked oil gally passage near an exhaust port, or possibly the head on that side is cracked and the excess oil from the valve spring area is leaking into an exhaust port. Maybe the oil drainback passages are clogged and the oil is seeping into an exhaust port. It definitely sounds like there is no oil in the combustion chambers. Way out there, SMOG PUMP pumping oil into that head at the exhaust ports, but then I would think it would be on the other side too. Good luck
  25. Ebbsspeed
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    Ebbsspeed
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    Hot moist air (ie., exhaust) flowing through a cool pipe will condense water on the pipe and eventually blow it out somewhere, or it will drip out weep holes in the mufflers. It's most likely to happen on a cool day, or on a really humid day when there's lots of moisture in the air. Same reason your cold beer can gets wet on the outside on a warm day.

    Depends on the exhaust system. If you're familiar with what is called a "heat riser", it would explain the one side only deal. What a heat riser does is closes off one side of the exhaust system below the manifold when the engine is cold. This forces the hot exhaust gasses to flow through the heat riser ports in that head, through the intake manifold, and back out the heat riser port on the other head, then into the exhaust manifold. The purpose is to build heat under the carb as rapidly as possible. I would suspect that virtually all of the cars owned by HAMBers no longer have the heat riser valve installed. If this guy you bought the motor from is as anal as you mentioned, his 78 Cheyenne probably still has an original style exhaust system on it, including the heat riser valve.
  26. BlackCherryImpala
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    BlackCherryImpala Member

    Thanks so much guys. You all are appreciated.
    BlackCherry
  27. dirty old man
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    dirty old man
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    So what have you done? Keep us advised.
    Dave

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