N14 Top End Knock

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by SpeedyGonzalez, Sep 3, 2019.

  1. xsetra

    xsetra Road Train Member

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    Google Play
    Manualslib - User Guides & Owners Manuals library
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    Try this link search:
    Cummins n14
    That should get the shop manual.
    Good luck.
     
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  3. SmokinCAT

    SmokinCAT Road Train Member

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    Diesel Controls does good work, but the shop I am buying big cam parts from now also does N14 injectors and that is where I have been sending people.

    Premco out of Lampasas, TX.
     
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  4. SpeedyGonzalez

    SpeedyGonzalez Light Load Member

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    I have the shop manual, but its assuming a dry engine, and a fresh head lol. Dont have either of those but it does say to lube it up with oil so part 3 of the question solved. Kind of forgot I had a printed copy and a pdf on my phone.
     
  5. spindrift

    spindrift Road Train Member

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    There is a specific brush that is used to clean the injector cups. It MUST be used before the install. As far as fuel on the top of the piston is concerned, a plastic tube adapted to a vacuum is the best way to get down to the top of the piston.
     
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  6. SpeedyGonzalez

    SpeedyGonzalez Light Load Member

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    I'll give that a try, any ideas on where I could get one of those brushes, dealer couldn't find it in their catalog when I went today and Cummins HQ says they only sell to dealers and certified shops.
    Edit: found them online, it looks like theirs three, a spiral brush, and then two normal brushes. I'm assuming the spiral brush is the one to use, according to their site its stainless steel filaments.
     
    Last edited: Sep 5, 2019
  7. spindrift

    spindrift Road Train Member

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  8. SpeedyGonzalez

    SpeedyGonzalez Light Load Member

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    Thanks for the link, this one says copper bristles and I've got one ordered. I'm going to give a stiff bristle nylon brush a try and see if that will clean it out at all while I wait.
    The tech at the dealer is convinced the injector is stuck open and recommended I inspect the piston crown, the driver drove it about 1000 miles in its condition so I'm hoping the piston isn't torched. Any odds on the likelihood its torched?
     
    Last edited: Sep 6, 2019
  9. spindrift

    spindrift Road Train Member

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    If he was seeing a lot of black smoke it's highly likely that it got too hot.

    Nylon bristles are worthless.
     
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  10. Dave_in_AZ

    Dave_in_AZ Road Train Member

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    Last edited: Sep 6, 2019
  11. SpeedyGonzalez

    SpeedyGonzalez Light Load Member

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    Not a hint of smoke according to the driver, I tailed him empty for a few city miles and there wasn't any smoke then either. Couldn't find my thermometer but feeling the exhaust manifold, number 1 and 2 holes were about the same temp at idle, he said if it was stuck open it would be too hot to touch seconds from start up. Unplugging the injector gets rid of the knock but RPM stays about the same, doesn't drop just gets rid of the knocking noise.
    I'm with you on the nylon, but figured it would be worth the try, driver wants to get back on the road ASAP and it's either a nylon brush or some brass wool for cleaning it out because he doesn't want to stick around for the end of the weekend.
     
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