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One washed / clean piston

Discussion in 'The Hokey Ass Message Board' started by scoggman, Oct 14, 2013.

  1. scoggman
    Joined: Feb 25, 2009
    Posts: 478

    scoggman
    Member

    Well, I bought a smoking 350 off of craigslist, but it was only smoking on one side (oil in tail pipe). last night I pulled the head off of that one side, and 3 of the pistons looked normal, the other looked clean or washed. The head had a lot of carbon build up on that one cylinder.

    You could still see the hone marks in that one cylinder, and not the others. Does this mean someone has already tried to re-ring this cylinder? Would re-ringing fix the issue?

    Let me know what you guys think.

    Thanks,
    Scoggman

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  2. FiddyFour
    Joined: Dec 31, 2004
    Posts: 9,008

    FiddyFour
    Member

    did you do a compression test before you tore it down?
     
  3. squirrel
    Joined: Sep 23, 2004
    Posts: 49,261

    squirrel
    Member

    is the cam lobe wore off on that cylinder?
     
  4. john walker
    Joined: Sep 11, 2008
    Posts: 1,116

    john walker
    Member

    lots of oil use through that hole. valve guides or rings shot.
     

  5. blowby
    Joined: Dec 27, 2012
    Posts: 7,738

    blowby
    Member
    from Nicasio Ca

    Do the other pistons have the same stamping this one does between the bottom valve reliefs?
     
  6. A picton with no carbon on the top when the others are carboned up could be in indication of water in that cylinder. Even mild seepage would keep the carbon o softened to the point of getting blown off when the engine is running.

    You have it down that far I would at the very least pull that piston and check for cylinder to wall clearance and get a look at the rings check wend gap etc.
     
  7. 2racer
    Joined: Sep 1, 2011
    Posts: 960

    2racer
    Member

    leaking head gasket
     
  8. blowby
    Joined: Dec 27, 2012
    Posts: 7,738

    blowby
    Member
    from Nicasio Ca

    Wouldn't the head be cleaner too?
     
  9. BigAl1961
    Joined: Dec 22, 2010
    Posts: 116

    BigAl1961
    Member

    Broken rings.
     
  10. Not always. I have seen them with just the piston clean. Normally you would thing that anything that would make the piston clean would also make the head clean but it is not always the case.

    look at the piston it was sooted at one point and got clean not clean from the start and never got dirty.
     
  11. scoggman
    Joined: Feb 25, 2009
    Posts: 478

    scoggman
    Member

    Well.... I thought I struck gold.... but then it turned out to be copper.... I pulled out that one clean piston and the two ring gaps were lined dead nuts up together! Victory! but the I pulled off a main cap, and it looked pretty ruff! some pretty deep grooves... not quite catch a nail on it, but almost....

    So what to do now.... how bad is bad on a crank? It is already a .010 crank.... This motor is only to get me going till I can save up for a crate motor.

    Should I put new bearing in it, or whould that cause more harm than good?

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  12. Larry T
    Joined: Nov 24, 2004
    Posts: 7,667

    Larry T
    Member

    Piston rings float in the ring groove and rotate all the time, right? If they didn't you would have grooves in pistons and rings that matched. So at some time they are gonna be lined up. I don't see where that's gonna be a problem unless the ring gap is excessive. I'd keep looking for another problem, or put Z Gap rings in every cylinder.
     
  13. squirrel
    Joined: Sep 23, 2004
    Posts: 49,261

    squirrel
    Member

    is it missing the oil ring scraper rails? hard to tell from the pictures.

    the ring gaps lined up probably wont' cause that much mayhem.
     
  14. 35desoto
    Joined: Oct 6, 2009
    Posts: 770

    35desoto
    Member

    She's pretty worn in that bearing for that much copper to be showing
    I would be pulling the whole motor down and measuring and checking everything - that ol girl has seen plenty of action and needs some TLC.
     
  15. dirty old man
    Joined: Feb 2, 2008
    Posts: 8,912

    dirty old man
    ALLIANCE MEMBER

    x-2
     
  16. You can't tell how bad a crank is without a micrometer. It will turn .030 without any problems if all you are going to do it drive it. If it is not flat then all it should need is a minimal turning if it needs turning at all. maybe get by with a polishing, I am not there so I cannot tell you.

    I would trear it down and give it a good going over. There is actually a thread that gives you some idea what to look for and how to go about a simple tear down and inspection that you should tak a look at before you start tearing things apart. Let me find you a link.

    maybe this will help a bit:

    http://www.jalopyjournal.com/forum/showthread.php?t=679583
     
  17. txturbo
    Joined: Oct 23, 2009
    Posts: 1,771

    txturbo
    Member

    Probably burning coolant in that cylinder due to a crack or leaking head gasket. Then after a while the rings on that piston got stuck causing the excessive oiling. I've bought cars before that blew head gaskets from over heating and then they sat up for a period of time. Usually I can fix the initial problem and get it running again and then do the marvel mystery oil treatment to unstick the rings. Has worked for me several times.
     
  18. Larry T
    Joined: Nov 24, 2004
    Posts: 7,667

    Larry T
    Member

    Rings sure don't look stuck to me. And I've never seen ring grooves much cleaner than those. I'd guess it hasn't been many miles since the engine had been apart.

    The tops of the other pistons don't have enough carbon on them to be an "old" engine.
     
  19. squirrel
    Joined: Sep 23, 2004
    Posts: 49,261

    squirrel
    Member

    really, doesn't the oil ring look strange to you? Am I nuts?
     
  20. 34toddster
    Joined: Mar 28, 2006
    Posts: 1,482

    34toddster
    Member
    from Missouri

    I'm with Squirrel, does that piston have all of the oil rings installed? The copper on the bearing might be from coolant in the oil over a long period of time
     
  21. blowby
    Joined: Dec 27, 2012
    Posts: 7,738

    blowby
    Member
    from Nicasio Ca

    Not nuts, looks like the rials are missing.
     
  22. jbrittonjr
    Joined: Sep 10, 2009
    Posts: 105

    jbrittonjr
    Member

    I see a spacer but no oil scraper rings in the first picture of post 11.
     
  23. txturbo
    Joined: Oct 23, 2009
    Posts: 1,771

    txturbo
    Member

    I can't tell much from those pics when viewing them on my phone.....but it does look like the bottom oil ring is missing. It's a fuzzy pic when I zoom in on my phone but looks like the top ring is there and the expander....that's all.
     
  24. scoggman
    Joined: Feb 25, 2009
    Posts: 478

    scoggman
    Member

    It has three rings total, one crazy one (Oil ring I am assuming) and two standard rings. I that it, or are there supposed to be rings on each side of the crazy looking oil ring?

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  25. Larry T
    Joined: Nov 24, 2004
    Posts: 7,667

    Larry T
    Member

    Yes. Oil ring uses an expander and two oil rails. You might as well leave the expander out if you don't have the rails.
     
  26. Yes there are supposed to be two very thin rings on each side of the zig zag expander. They are oil control rings, and the zig zag thing keeps them "expanded" into the top and bottom of the piston groove.

    I'd guess someone was in there that didnt know what was going on.
    I'd also guess there isn't much run time since they were in there. Why they changed a piston ??? Could be a bunch of reasons why. But that bearing wouldn't make me happy.

    You could check that crank journal for egg shape with a dial indicator but it will have to come out to get a micrometer on it. An egg shape journal from a rod knock will wipe a bearing like that.
     
  27. Is that a rod or main bearing?
     
  28. dana barlow
    Joined: May 30, 2006
    Posts: 4,395

    dana barlow
    Member
    from Miami Fla.
    1. Y-blocks

    This post is a sign you really need to get a buddy that knows motors to help you with it,and you'll learn from it.. Or find another running motor to work for you tell your crate deal happens.
     
  29. squirrel
    Joined: Sep 23, 2004
    Posts: 49,261

    squirrel
    Member

    it looks like a main, it's the size it would be to fit in the main cap that is right behind it in the picture, and he mentioned that he pulled a main bearing and it looked rough.
     
  30. From Mahle;
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