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Thread: Caterpillar 951c replacement seal converter.

  1. #21
    Join Date
    Dec 2006
    Location
    victoria australia
    Posts
    2,977

    Default Exhaust Manifold Gaskets

    Hi Team,
    simple things first----from the look of the muffler/silencer the top is rusted from it which can make the noise but not the smoke.
    First I would check the inlet and exhaust manifold gaskets--sounds like inlet turbo pressure or exhaust gas pressure leaking from one or more manifold ports--this is the clacking/hissing sound I feel I can hear.

    For the exhaust, check for tell tale black soot lines from the manifold elbow areas streaking on the cylinder head or cylinder block faces or nearby parts.
    Could be exhaust manifold to turbo gasket leaking too.
    Inlet leaks could maybe a possible oily streak.

    Leaks from one or the other manifolds causes low turbo boost and so more fuel can be injected than is needed for the amount of air in the cylinder due to low boost pressures.

    Do all the injector lines look to have the same paint finish or is one a new rusty one or a different color--there are different bore fuel lines for different engine applications and an incorrect one can cause a hard to find uneven running cylinder--use small drills inserted gently into the ends of the lines to check all the bores are the same--sometimes the ferrule on the end of the fuel line can be collapsed in from over tightening and can cause similar effects. Weld repairs to injection lines can part block them as well and cause uneven running.

    A small amount of fuel leaking from the splined injection pump nut area would cause less fuel to be injected for that cylinder and not usually the black smoke we see--could still be a faulty injector even though they are new.

    If you have puffs of black smoke then loosen each injector pipe in turn and see if you can isolate the faulty cylinder/injector. You could swap the maybe faulty injector to another cylinder and re/test to see if the fault goes to another cylinder.

    Safety Warning--
    cover the injector line area with a rag so you do not get squirted by injecting spurts of fuel, keep fingers etc. out of fuel spray as it can penetrate the skin and cause blood poisoning or worse.

    Just some simple things to check before spending big money.

    Hope this helps,
    Cheers,
    Eddie B.

  2. #22
    Join Date
    Jan 2019
    Location
    italia
    Posts
    83

    Default

    hello thanks a lot. Eddie
    The engine smoked the same, so I decided to replace the injectors. but nothing has changed.
    One thing that happens is this.
    with the engine cold not all the pistons come on, you have to wait 10/20 seconds even more ... it bursts badly and makes so much white smoke.
    When the engine is very hot it's better.
    I enclose another video, in the final part we note that accelerating abruptly fails to burn fuel quickly.

  3. #23
    Join Date
    Nov 2006
    Location
    Corralitos, Ca.
    Posts
    14,528

    Default

    What have you done to check what cylinders are affected (or all)?
    Why did you not respond with requested fuel pressure indicated?
    That engine has provision with timing pins to check injection pump timing. Do you know how to do that and to reset timing if required?
    Sleeve metering pumps are very sensitive to air or water in the fuel. Has there been any history of water or air leaks in the fuel system?
    Is there any spitting/pulsing in the exhaust flow that would indicate engine valve sealing problems?
    Does the engine burn excessive lube oil?

  4. #24
    Join Date
    Jan 2019
    Location
    italia
    Posts
    83

    Default



    the sound is better understood

    what do you mean spit / pulse?
    yes, there seems to be spit of smoke out of time ..

    hi i'm no expert.
    mine are beginner's deductions does not burn oil remains constant.
    it had leaked water from the radiator but was repaired.
    loses from a fuel canister and from the pump, very little.
    seems out of phase.
    I wouldn't know how to check the valves.
    if I accelerate abruptly it smokes a lot and sobs.
    how and what should be checked.
    I wanted to thank you all ..
    Last edited by uisum; 05-15-2019 at 12:55 PM.

  5. #25
    Join Date
    Nov 2006
    Location
    California City, CA USA
    Posts
    521

    Default Exhaust Restriction?

    I don't understand the exhaust restriction on the stack. It seems to only allow ~ 20%-25% of the area of the pipe to 'freely' flow.

    Daron

  6. #26
    Join Date
    Nov 2007
    Location
    NW Ohio
    Posts
    3,230

    Default

    Its either pump timing or bad valves. Find a diesel mechanic or shop to check it.

  7. #27
    Join Date
    Nov 2006
    Location
    Corralitos, Ca.
    Posts
    14,528

    Default

    Quote Originally Posted by daron View Post
    I don't understand the exhaust restriction on the stack. It seems to only allow ~ 20%-25% of the area of the pipe to 'freely' flow.

    Daron
    That appears to be a 2P6252 muffler, part of 1V3623 & 3V0560 sound suppression arrangement (an attachment)

  8. #28
    Join Date
    Jan 2019
    Location
    italia
    Posts
    83

    Default

    yes the muffler is gone, but the smoke comes out quite freely. I tried it without the muffler and the smoke is the same.
    another clue.
    It has happened a few times that the engine accelerates alone. The fuel pressure is low even at maximum. maybe the gauge is broken.
    When the engine is hot it gets better, the smoke seems to decrease and burn better. It has a lot of strength. The engine starts immediately and quickly, but sobs and then aligns correctly.
    A lot of steam comes out of the oil vent.
    The water from the radiator tries to get out of the (large) radiator cap, even if it is tight.
    The water level is below the caps under the upper cup.
    In acceleration it seems drowned.

  9. #29
    Join Date
    Nov 2007
    Location
    NW Ohio
    Posts
    3,230

    Default

    Pull the head.

  10. #30
    Join Date
    Jan 2019
    Location
    italia
    Posts
    83

    Default

    Quote Originally Posted by Rome K/G View Post
    Pull the head.
    Hi , What do you mean?

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