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  1. #1
    RC poster
    Join Date
    Jan 2007
    Posts
    6

    how do you know when its time to re-build?

    i was just courious to when you can tell your car needs a re-build, i have a 2.5 jato, and i was noticing the other day that after it was warm and running, it still seemed like somthing wasnt right, like it wasnt running as good as it did, its had a gallon of fuel ran threw it and here latley seems like it has lost about 20 or 30% power through out the entire powerband, is this a good sign of needing a re-build? Oh and i removed the head and it seemed to me that it wasnt sealed up real good and that it had some blowby where it seals up.....is this possible also?

  2. #2
    RC Qualifier
    Join Date
    Jan 2007
    Location
    Kempsey,Australia
    Posts
    709
    I think its time for a rebuild.
    You can useually tell because it is hard to tune runs really hot and has lost power.
    Tmaxx for sale. Look in the Market Section

  3. #3
    RC Competitor
    Join Date
    Sep 2006
    Location
    Satsuma, Al
    Posts
    51
    If you did the break in properly, haven't overheated it, and kept your air filter clean you shouldn't need a rebuild yet. Any leak on the motor can cause problems, tuning, power loss, etc. Does it crank easily, have you retuned the carb, have you been running it lean, has the outside temperature changed considerably since it ran good? All of these things can affect the life or performance of the motor.

    Do you have a temp gun? When the motor overheats it will lose power. Check all of these things out and maybe retune from factory settings. Maybe it will be OK then.

    Good Luck

  4. #4
    RC Racer
    Join Date
    Jan 2007
    Location
    Dudley, NC
    Posts
    204
    Is hard starting a sign it is going bad?
    Alan

  5. #5
    RC Racer
    Join Date
    Dec 2006
    Location
    Philly
    Posts
    115
    hard starting is a good sign.

    actually, maybe just a rebuild.

  6. #6
    RC Enthusiast
    Join Date
    Jan 2007
    Location
    Southeast Texas
    Posts
    47
    I doubt it is time for a rebuild, I have run over 10 gallons of fuel through mine. Although I do after run procedures every time I am done running.
    If it starts acting sluggish, clean your air filter, change your glow plug, tune your engine(HSN, LSN & idle). Then if it still is acting sluggish, Check the fuel!

    The fuel maybe bad.
    If it has a hazy color, it most likely has gotten moisture in it.
    (If your not sure if it is hazy buy a fresh gallon and compare the two colors.)

    (Do not put a freshly washed air filter in the car, even if you oil it. There is still a lot of moisture still in it. Also if the underside of the air filter is wet from fuel, that will impede air flow.)

    Make sure the engine head seal is in good condition, if you are losing compression due to a leak. Reset the head with a new seal and see if it still leaks.

  7. #7
    RC Enthusiast
    Join Date
    Feb 2007
    Posts
    46
    How can you tell if its losing compression I have a compression tester with an array of nozzles that Im sure one will fit? What the stock compression supposed to be anyway? Sorri bout the questions and the thread jacking

  8. #8
    RC Champion
    Join Date
    Sep 2005
    Location
    Cambridge, England
    Posts
    1,837
    its hard to test the compression, but if you have a nozzle that will screw into the glow plug hole and make a good seal that would be an easy way to test it. there are other methods like taking the piston and sleeve out of the engine and pushing the piston into the sleeve and if it can go further than the end of the sleeve then it will need to be replaced, but don't push it too hard because you might damage a good piston and sleeve. for more information about it look here:
    http://misbehavin-rc.com/pit-lane/wo...worn-motor.asp

    there's also alot of useful information on that website about nitro engines.

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